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Engine Specific Info and Questions => IDI Engine => Topic started by: fspGTD on April 11, 2005, 06:03:37 pm
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My dad's '84 Rabbit (1.6l NA Diesel, 2-door, atlas grey) ran low on coolant late last week and seems to now have developed a leaking headgasket. He said there was excess white smoke out the exhaust, and then he found a low coolant level - it like sounds like the coolant was leaking into the combustion chamber to me. The plan is that I'm going to fix it for him, and do other work that it needs that makes sense at the same time (like motor mounts and timing belt), and maybe a turbo upgrade. Since it sounds like he caught and shut down the motor before the overheat got really serious, I'm optimistic there are good prospects that we can get by with a headgasket replacement and not a head rebuild. I think there was a slow coolant leak out of a cracked expansion chamber which was caused by overpressure from a faulty coolant pressure relief valve. I'd plan on checking the head with a straightedge to verify no permanent warpage after I get the head off. This motor is a good rebuild still with relatively low miles for what these are capable of; it uses one quart of oil per 6 tanks I think dad said. Not really good, but not bad either. Always easy to cold start so seems to have good compression. I will be putting the head back on there probably with some raceware head studs I have been saving for it.
We have been toying with the idea of upgrading this motor to turbo for quite a while now, and this time when the head comes off, it might be the right time to go the whole nine yards and do the turbo upgrade while it's down. Since it doesn't have piston squirters, my plan would be to run the fueling conservatively, and/or use a big free flowing exhaust. We have already prepared the car in this department by installing a 2.25" techtonics exhaust which is on there, which is what I'd run with the turbo.
The question on my mind at the moment is turbo selection. This car is dad's daily driver, and I'd love to set him up with a sweet performing ride, and maybe experiment a little bit in the process if it is a calculate risk. We've got a complete 1.6lTD turbo external bolt-on setup collected here (with the big KKK turbo), which I know would work and is generally a "bolt on" option. But, we also have collected a used 40k mile old"ALH" TDI variable vane turbo that I know to be in good condition. I am considering the ALH variable vane turbo vs the factory 1.6lTD turbo. With the ALH turbo, torque would be monstrous, especially if it were coupled with a long-runner gasser intake. With either turbo, the downpipe will need some work if we want it to be free-flowing, the stock 1.6lTD downpipe is not an option. So it might not be a lot of extra work to adapt the different turbine outlet position of the ALH. The other factor is that the air intake system with the ALH variable vane turbo would need to be changed (and custom). But to install the 1.6lTD airbox would require welding the airbox moutning bracket, which isn't so easy for me to do anyway, so again in the department of the airbox and air intake, it might not be incrementally that much more work to adapt the ALH turbo. In either case the fuel filter will need to be relocated (I think) and I haven't decided if factory TD position will be used welding on the bracket to the firewall, or to adapt to the in-fender fuel filter location that I have been very happy with on my GTD Autocrosser. Regarding ALH turbo boost control, I worked out a few weeks ago on a napkin I put somewhere a scheme for controlling the boost of the "ALH" wastegate involving vacuum, manifold pressure, and some variable bleeder valves. It is completely untested, but it might just work! I need to go and find it. I am thinking I would want to run unintercooled to keep the project simple and not dragging on too long, at least initially.
Just throwing out ideas at this point for your guys consideration / comments... whatever the plans are, the project will be starting very soon, in order to try and minimize turn-around time and get dad's daily driver back on the road with minimum of delay. I might go to the shop to rip the head off of it tonight or tomorrow...
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I'd go with the TDI turbo. Instant boost is awesome :)
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Sweet. Scan that diagram of the VNT controller and post it! I'd love to see what you came up with. It seems the TDI VNT is a tad small for the TDI when more performance is desired out of it. Running stock-ish boost levels (for the TDI) on a 1.6, which I think is somewhere around 14-16 psi, would probably be a pretty sweet ride, and the VNT's size should keep it fed with plenty of air at the top end too. That much low-end boost should make it fly off the line as well.
I'm still toying with what I actually want to do with the Rocco, (although I am still just getting it back together in gasser form!) as 1.6T's are REALLY hard to find anymore, a 1.9IDI would be sweet but even more rare, a TDI would be nice, but I want a little more rpm potential than I think a TDI could provide. Pretty much all options are out of my budget now, but the prices of salvage TDI's are coming down, and finding a mechanical pump to run it shouldnt be too hard either.
Depending on how this experiment comes together, it might help my decision some. Who knows, maybe the VNT turbo will really make these 1.6's into hot-rods. :)
Good luck, we will be waiting. :twisted:
Brendan
84 Scirocco 8v
00 Camaro L36 M49
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In the "normal" configuration the VNT vanes are pulled in to the "closed" or max boost position by vacuum, the modulating solenoid then bleeds in atmospheric pressure as commanded by the ECU to reduce the boost. It would stand to reason that you could just spring the VNT actuator fully closed and then use boost pressure at the vacuum fitting to open the vanes as the pressure rises. Springs are cheap, simple and reliable like an anvil.
I don't think it would be too difficult to fab up some kind of bracket to use a spring on the actuator, then hit the local industrial supply for the proper spring. You can get a rough idea of what you need by calculating the area of the diaphram, from there you can establish the force required to hold the vanes closed up to your desired boost level. It would take some fiddling but I'm sure it could be made to work. I use a "helper spring" of sorts on my (K03 external actuator) wastegate to increase the boost pressure without resorting to bleeds and other messy plumbing, works quite well.
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sounds great, I have been toying with the idea of going to a VNT 17 or 20 instead of twins, but I think the bling factor and the cheapness factor will keep me to twins.
However back on topic QuickTD mentioned "In the "normal" configuration the VNT vanes are pulled in to the "closed" or max boost position by vacuum, the modulating solenoid then bleeds in atmospheric pressure as commanded by the ECU to reduce the boost. It would stand to reason that you could just spring the VNT actuator fully closed and then use boost pressure at the vacuum fitting to open the vanes as the pressure rises. Springs are cheap, simple and reliable like an anvil."
As I reacall it seems that there is another smaller port on the back side of the actuator that you can just run boost into to have the vanes move, however you "MAY" need to be able to contorol how much boost, and how fast it comes on, as it may only take a few pounds to move the vanes there full cycle or it may be somewhat linear, things that need to be worked through, but should be simple enough to solve. My vote is definalty VNT.
If there is anything that you need fabbed for the project that wouldn't be really costly to ship, or wouldn't need trial and error fitment let me know, I will do my best to help you out. (I have CNC plasma, and MIG setup for mild steel, our TIG is on the road for the next bit, so no aluminum or stainless welding right now, but I can still cut it.)
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In the "normal" configuration the VNT vanes are pulled in to the "closed" or max boost position by vacuum, the modulating solenoid then bleeds in atmospheric pressure as commanded by the ECU to reduce the boost. It would stand to reason that you could just spring the VNT actuator fully closed and then use boost pressure at the vacuum fitting to open the vanes as the pressure rises. Springs are cheap, simple and reliable like an anvil.
I don't think it would be too difficult to fab up some kind of bracket to use a spring on the actuator, then hit the local industrial supply for the proper spring. You can get a rough idea of what you need by calculating the area of the diaphram, from there you can establish the force required to hold the vanes closed up to your desired boost level. It would take some fiddling but I'm sure it could be made to work. I use a "helper spring" of sorts on my (K03 external actuator) wastegate to increase the boost pressure without resorting to bleeds and other messy plumbing, works quite well.
Hmm! I am liking that idea! I am going to take a closer look at the diaphgram mechanism. Maybe I can open it up and change the spring from one side to the other of the diaphgram. And I agree in theory at least, that it would work!
I found the sketch of my other idea. It connects vacuum from the vacuum pump to the vane control diaphgram through a restrictor... let's call that restrictor "R1". It also has a "T" connection at the vane control diaphgram so it is also connected through another restrictor ("R2") to manifold pressure.
My conjecture is that by varying R1 and R2, boost control could be tuned without any modification being required to the diaphgram housing or vane control system.
I worked out a few scenarios... here is how the numbers would work out, as well as some things I determined...
(Note: resistance of zero means there is no resitrction to airflow. A greater resistance means a smaller orifice that restricts airflow more. Negative pressure numbers mean pressure is vacuum, zero pressure means atmospheric pressure, and positive pressure means that pressure is above atmospheric. Assuming vacuum pump pulls -14psi.)
Things we know about the vane control mechanism:
* When vane diaphgram pressure is low enough (far enough negative) the vanes will more into a closed position, causing turbo to speed up and boost pressure to increase.
* When vane diaphgram pressure is high enough (which is a negative number but may be close to 0) the vanes will be in an open position which will cause turbo to slow down and boost pressure to decrease.
* When R1 = R2: If boost = 0, vane diaphgram pressure = -7 psi. (possibly completely or partially closed?) If boost = 15 psi, vane diaphgram pressure = 0 psi (completely open.)
* To increase boost pressure, increase R2 and decrease R1.
Example: When R2 = 2 x R1: If boost = 0, vane diaphgram = -10 psi. If boost = 15psi, vane diaphgram = -5 psi.
* More restriction (R1 + R2) makes less flow (load) through the vacuum pump, but slower reacting vanes.
How to tune it depends how quick you want it to react (I would want as quick reacting without fluttering while not causing too much burden on vacuum pump), how much max boost pressure is desired, and how much vacuum is necessary to get the vanes to open and close. But if 2 variable bleeder values were used, it would be fiddled with pretty easily it seems. I can say that the vane mechanism is completely open at atmospheric pressure, and seems to need some amount of vacuum before it starts moving towards closed (I just don't know how much.) I also don't know how much vacuum is needed to completely close the vanes.
The OEM TDI N75 electronic solenoid valve is similar to the concept proposed above in that R1 is fixed and it connects vane control diaphgram to vacuum pump, but is different in that R2 is variable and connects vane control diaphgram to constant atmospheric pressure source (pressure = 0).
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As I reacall it seems that there is another smaller port on the back side of the actuator that you can just run boost into to have the vanes move
I thought of that possibility also, but wasn't able to make it work. It would require the linkage coming out of the turbo side of the VNT actuator diaphgram "can", which moves in and out of the can, would need to be sealed airtight to the opening of the "can". I couldn't think of a way that the setup could be easily modified at least that would achieve this.
If there is anything that you need fabbed for the project that wouldn't be really costly to ship, or wouldn't need trial and error fitment let me know, I will do my best to help you out. (I have CNC plasma, and MIG setup for mild steel, our TIG is on the road for the next bit, so no aluminum or stainless welding right now, but I can still cut it.)
Nice... thanks for the help, that is some sweet equipment you've got access to. I will keep it in mind! :D
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Good to know about the linkage ect... hopefully either QuickTD's idea with the spring or your restrictors, or a combination will work! I'm now having dreams of a twin setup with a VNT on the small side and a ball bearing garrett or a pdr holset on top. :twisted: Monster bottom end torque massive topend flow. 8)
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I got the VNT diaphgram can off and took some measurements and some pics:
(http://www.imagestation.com/picture/sraid164/pb3cbf8d54a5527c53372918f45cac9b5/f47bca9e.jpg)
(http://www.imagestation.com/picture/sraid164/p2f7404e0eaf10bf4a47f86823adcd3d9/f47bcbf4.jpg) (http://www.imagestation.com/picture/sraid164/pc0b034ec2297b9e1673a446e0ade4e41/f47bcaff.jpg)
(http://www.imagestation.com/picture/sraid164/pa3878755b52c7019e3792caaf414880a/f47bcb9b.jpg)
It takes 3 pounds force before it begins to move. It reaches the end of it's travel when 40 pounds of force are applied, and the length of its travel is 5/8". The inside diameter of the can is about 2 7/16", which gives the diaphgram an area of approx 4.66 square inches.
That means it would take -.6 psi (vacuum) to make it start to move and -8.6 psi (vacuum) to make it reach the end of its travel. I am able to make it reach the end of its travel by applying suction with my mouth by the way.
Note that the actual travel of the VNT mechanism is probably somewhat less than the full travel of the diaphgram can.
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re: QuickTD's idea of opening the can and changing the spring
Unfortunately, the can is crimped together, and I can't figure out how to undo the crimp without damaging the can. It looks like it is swaged together and is not designed to be disassembled. You can see in the pics the band around it which is where the crimp is. Does anyone know how to disassemble it so that it can be reassembled afterwards? If I have confidence I can disassemble it without destroying it, I would be willing to try it. But right now I can't figure a way it can be done.
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Does anyone know how to disassemble it so that it can be reassembled afterwards?
Maybe dremmel around the crimp with a thin cutting wheel a little a t a time so it does not get to hot and melt stuff inside.
then reassemble it with 2 large home made washers with the diameter of the hole in the "washers" the same as the OD of the whole actuator, 3 or 4 nuts and bolts around those two two large "washers" (one on each side of the drimp) and mabye a bit of sillycone before reassembly to ensure a good seal.
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Does anyone know how much vacuum our vacuum pump pulls?
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That idea to clamp two washers together around the outside of the can might just work! But I wonder where I would get washers with inside diameters that large? The inside diameter would need to be about 2 9/16".
I think I might re-install the VNT diaphragm can onto the turbocharger, and measure the amount of travel it requires to the "full closed" position so I can calculate the require vacuum to completely close the vanes (or if I can find a vacuum gauge, I would hook it up and directly measure the vacuum required.)
I whipped up an excel spreadsheet I am using to calculate the wastegate can pressure from various manifold pressures and various R2 to R1 relationships. I am hopeful there is a setting that is workable... the ideal goal would to have the VNT vanes be in a full closed position at 0 psi manifold pressure, but full open at not too high (IE: not much over 10psi) positive manifold pressure. This could be a viable scheme if the vacuum pump pulls strongly enough, and/or if the vacuum required in the VNT diaphgram can to move the vanes completely closed is weak enogh.
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Here is a drawing of what I was trying to describe earlier,
(http://img12.echo.cx/img12/962/scan00048uo.jpg)
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Great pic! :)
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That idea to clamp two washers together around the outside of the can might just work! But I wonder where I would get washers with inside diameters that large? The inside diameter would need to be about 2 9/16".
It would be a chore, but with a cutoff wheel in a dremmel then a sanding drum in a drill press you could make them, or dremmel then a carbide bit in adie grinder maybe?
:idea: Bi-metal Hole Saw would make some fairly quick and easy as well, but will probably be 15-20 bucks for the hole saw and hole saw mandrel.
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Is there anything specific about the form factor of the "can" other than the fact that it bolts to the turbo assembly?
I was thinking that maybe you could substitute some other type of vacuum chamber / actuator in its place. What about using some sort of external wastegate or BOV body and customizing it to do what you want?
I have several Audi 5kt wastegate bodies at home and I know they have a removable cap with a replaceable diaphragm. You can switch springs no problem and it all still seals up. Thinking again, that might not give you the linear "pull" you need to make the mechanism actuate.
Just an idea.
You know, that can looks like those actuators on the vac controlled vents/flaps in the VW's. Maybe you could practice opening / resealing with those? I've got a couple you could use.
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Interesting...
So how far up the power curve can you go with an N/A before meltdown; if there is no oil cooling to pistons, and no cooling through the oilcooler; and a weaker crank? What about the lack of boost from the aneroid setup?
When I disconnected the aneroid in search of the ultimate economy on my 'Q' ; the response was akin to a slug :lol: which was OK when passing a snail but not when trying to get past a smoke belching truck :?
(That reminds me my 3rd and final TD pump had the same '34' on the cone)
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I'm a little late to the party, but I'll share a few things regarding passive control of the VNT.
Alot of folks with high power TDIs will run a boost valve on their setup.
It's basically a spring loaded pop valve, and is used to control boost spikes.
It's connected between the intake manifold and the vacuum line controlling the VNT actuator. Under normal conditions, the valve is closed. If boost gets too high, it will bleed boost into the VNT line, and close the vanes, reducing the turbine speed, and reducing the boost.
One could, technically, run the VNT on full vacuum, then use a boost valve to limit the top end. The problem with that is the vanes would end up fluttering under full power, which wouldn't be good for the VNT.
Another passive boost control is 'the boost elbow'.
Connect the VNT actuator to full vacuum, with the boost elbow teed into the line. The other end goes to the intake manifold. The design of the elbow is such that you have a small set screw which controls the amount of boost which is bled into the VNT control line. At lower RPM, with little boost, the vanes are wide open, then as pressure builds, the vanes slowly back off as more pressure is bled into the VNT conrol line.
On an electronic TDI, (IE: ECU controlled), you can bypass the N75 valve and run the turbo under mechanical control without setting off DTCs.
The boost elbow ends up giving the diesel engine a dyno plot that looks very much like a gas engine.
TDIclub hosted dyno: (scroll down the page for the dyno)
http://forums.tdiclub.com/showflat.php?Cat=0&Number=802711&page=&fpart=2&vc=1
I say all this, but I have no idea what would work for a TD.
-Dave
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MrDave - thanks for posting your thoughts... I am still mulling and processing the information that you have contributed. (Edit: see below post for my reactions to these ideas.)
Mark the Miser - Re: thermal control for an engine lacking piston-oil squirters... I guess you missed the part of the plan which is to not set aggressive fueling levels. In any event, yesterday I ordered a VDO pyrometer to make sure the thermal limits are safe. I am planning on installing it pre-turbine into the exhaust manifold / turbine housing and will consider a red flag being raised if it approaches 1300 deg F (which is 200 deg. F cooler than the factory 1.6lTD.) I also never said I wasn't planning on running an oil cooler, or a TD fuel pump. (I was only in question about which type of oil cooler to run. I'm leaning towards the factory version at the moment by the way, mostly due to the fact that I already have it, and that it might be hard and expensive to track down a thermostatically control sandwich plate which I'd want if going external oil cooler route.) Also, re: your contention that the crankshaft differs between an '84 1.6lNA vs TD, show me some evidence that supports this notion, because according to ETKA as discussed on this board already, they have the same part number. I am planning on installing the TD harmonic balancer pulley.
I also wanted to update you all on where I am with the VNT can...
I first took some more measurements to determine the viability of my idea that wouldn't require modification of the can. I found a vacuum gauge in the shop that I could use so I can measure actual vacuum values, rather than estimate them from diaphgram area and forces.
The vacuum pump (this is an '84 Rabbit, with the compact vane-type vacuum pump not the diaphgram style by the way) pulls a very healthy -29 in Hg (that's -14.2psi.) Although that is for zero air flow, and I found that the vacuum strength gets weaker as flow increases.
The actual, as-installed amount of vacuum necessary to get the VNT mechanism to begin closing is -7.5 in Hg (-3.7 psi). -17.5 in Hg (-8.6 psi) is required to reach full closed. Then due to friction in the mechanism, the valued required to get the vanes to open are different: -16 in Hg (-7.9 psi) required for it to begin opening, and -2.0 in Hg (-1.0 psi) required to reach full open.
Putting all these numbers into my spreadsheet I built to predicts the vane movement for various boost levels and R2/R1 relationships, I found I'd need an R2/(R2+R1) to be 45% or less to make the vanes remain fully closed after the engine is started up when there is zero boost, and 40% or less to make the vanes return to fully closed after the engine has gone through a boost cycle.
At 45%, the vanes would reach full open at 15 psi, and wouldn't start to begin closing until boost dropped below 10psi.
At 40%, the vanes would reach full open at 19 psi, and wouldn't start to begin closing until boost dropped below 12psi.
I was hoping that there may be a relationship that would allow the vanes to be completely closed, and then open the vanes over a tighter boost range.
What does this mean? I decided I am not confident this scheme would reliably control the vanes in a narrow boost range. There is risk that this method may give boost creep, due to the wide range of boost pressure change necessary to get the vanes to move from full close to full open, and vice versa. And I'd rather not install the turbo with everything hooked up to find that it has to come off because I need to open up the can.
Result of this... gave me another reason to make the can open/closeable, and assess the viability of QuickTD's idea to convert the can from vacuum to pressure. Using a grinder, I thinned the metal around the outside rim or the crimp, and then I finished off removing the crimped on ring by carefully chiseling it off. After filing off any remnants of the crimp ring missed by the chisel, so there was nothing left to hold the can closed, I gently pryed the can open. For modification of the diaphgram to take boost rather than vacuum, I think the diaphgram will need to be flipped over along with it's rigid metal support behind it, to keep the metal support on the low pressure side and prevent the diaphgram from "balooning". To flip the diaphgram required that the linkage rod be removed (which was permanently riveted on.) The flipped over can with spring on the other side will have less room in the can to move around, due to the can and the diaphgram support being different on one side versus the other. However, I think there would end up being enough travel to completely move the vane mechanism, if the linkage were tuned correctly. I bought some various 6mm studs, threaded on both ends with a smooth center area, to experiment with replacing the riveted on linkage rod. I was able to install them to the diaphgram using nuts on either side of the diaphgram. I first tried a stud about 3" long but found it was too long, so went one step shorter. If I need to change anything, IE the rod length, change the diaphgram or can somehow to change it's travel of the spring pre-load, or change the spring, I wanted the can to be serviceable by just undoing some bolts, but I wanted it to also seal reliably.
I set about solving the problem of finding a clamping ring to seal the can back up. I bought a 4" wide plate of thick aluminum. And using my new dremel tool with router attachment that can do circles, I already precisely dremeled through a hole through the thick aluminum that has the needed 2 5/16"ID. My next step may be tricky, but I want to try and machining a relief in the edge of the aluminum, so that a shoulder sticks out past the outside of the can, so that the bolts I'm going to install holding the can together have a shoulder on the outside so they are evenly tensioned and not torqued.
I'll post pics of it later if I am successful, with me luck!
(If not, DVST8R, maybe I'll shoot you the details specs of the piece I am trying to fabricate and take advantage of your offer.) I am planning to clamp the can together with either 6 or 8 little bolts (6mm with wide bolt head).
PS - although I haven't taken any measurements of the pressure required to get the modified can to move the VNT mechanism, I did (with the can clamped together with a couple c-clamps) apply some pressure to the uninstalled can and determine the pressure required to move it's linkage. The results so far are encouraging. The resulting range to make the linkage start moving and reach full travel are: 6-7 psi to start moving out, and 10-12 psi to reach full extension.
I hope the range to actually pull the VNT mechanism open and closed is somewhere near this tight! :P I can always plumb in a bleeder valve if I want more boost pressure, so I was glad to see some pressure numbers that were in a reasonable or maybe slightly low range (I'd like to eventually target running around 10-14 psi boost level on this thing.)
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Another passive boost control is 'the boost elbow'.
Connect the VNT actuator to full vacuum, with the boost elbow teed into the line. The other end goes to the intake manifold. The design of the elbow is such that you have a small set screw which controls the amount of boost which is bled into the VNT control line. At lower RPM, with little boost, the vanes are wide open, then as pressure builds, the vanes slowly back off as more pressure is bled into the VNT conrol line.
OK, I now understand what you're saying about the "boost elbow". This is essentially the same idea I had, although omitting R1. This might have some adverse effect on vacuum pump life and there may also be a loss of vacuum if the vacuum pump flow required to set desired boost level is too high (In effect, it is equivalent to my scheme, except R1 would be hard-set to a very low resistance and not be adjustable.)
The effect you describe, "similar to a gas engine", is what I was worried about. And there basically just being too wide of a manifold pressure range required to move the vanes from full closed to full open. Essentially this would manifest itself as boost creep. In some settings, the vanes may never even get completely closed at zero boost.
The other idea you mentioned in your post, which is basically adapting an on/off flow valve into the system, would indeed solve the problem about there being too wide a manifold pressure range to get the VNT to move between full open and full closed, but indeed is also problematic because it makes the controlled pressure range too narrow. I would expect to see the opposite extreme of boost creep which is also undesirable... boost spike.
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Sounds like some great progress. If you could snap a few pics to aid us slow people challanged by visulizing just words that would be great too.
As for the pieces just let me know. If your good with auto cad you can just send me a 2 dimentional .dxf file with what you need and I can import that directly. If not just a dimentioned drawing and I will autocad it.
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DVST8R - thanks. I have already snapped a few pics of the disassembled VNT can... I have just left the digi cam out at the shop right now and have not downloaded the pics yet, and it is not currently accessible from home. I will make a note to grab the camera next time I get to the shop so I can show you all the disassembled VNT can (and maybe snap some shots of my aluminum plate washer fabrication in progress ;) )
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The effect you describe, "similar to a gas engine", is what I was worried about. And there basically just being too wide of a manifold pressure range required to move the vanes from full closed to full open. And in some settings, the vanes never get completely closed at zero boost, which may adversely effect low-RPM torque and turbo lag.
The other idea, which is basically adapting an on/off flow valve into the system, indeed raises concerns in my view about flutter due to the system controlling VNT movement over too narrow of a boost range.
Actually, at low rpm or zero boost, the can would see full vacuum, so there is minimal turbo lag once you get on the go pedal. As vs. the ECU control where the can would be under atmospheric pressure, till you tell the ECU you want to go, THEN it puts it under vacuum.
One idea I had was to connect multiple boost elbows in parallel as a passive system, and a boost valve to limit max boost. Multiple elbows should essentially allow you to tune your boost curve.
Another idea would be to have a boost valve bleed into a boost elbow.
ie: at 5lbs start bleeding in. Under 5lbs, no bleed at all.
Other ideas would be for an electric vacuum source. Think electric mitivac...
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Actually, at low rpm or zero boost, the can would see full vacuum, so there is minimal turbo lag once you get on the go pedal. As vs. the ECU control where the can would be under atmospheric pressure, till you tell the ECU you want to go, THEN it puts it under vacuum.
Gotcha - the TDI computer keeps vanes open at low throttle settings, probably to increase fuel economy. Although if the restrictor between manifold and VNT can is open enough, vacuum inside the VNT can may not be high enough to get the mechanism completely closed. For example, if you had equal restrictions between vnt can and vacuum pump as there is between vnt can and manifold, according to my calculation there would not be enough vacuum in the VNT can to fully close the vanes.
One idea I had was to connect multiple boost elbows in parallel as a passive system, and a boost valve to limit max boost. Multiple elbows should essentially allow you to tune your boost curve.
Another idea would be to have a boost valve bleed into a boost elbow.
ie: at 5lbs start bleeding in. Under 5lbs, no bleed at all.
Other ideas would be for an electric vacuum source. Think electric mitivac...
Re: Multiple "boost elbows" in parallel... I might be picturing something different than you're describing, but connecting two lines in parallel I don't see offering any more flexibility than a single line with a variable restriction, where if you want more flow you just set the restrictor to be more "open" (less restrictive.)
By "boost valve" are you referring to a boost pressure controlled airflow valve that is either on (low restriction) or off (high restriction)?
Is a spring loaded pop valve a restriction that is closed until pressure exceeds a certain differential, and then it varies flow to try and maintain that amount of differential? Or do I have these two mixed up?
In any event, I don't see the laws of mechanical VNT boost control being much at all different 1.9l TDI vs 1.6l IDI... So if you guys have already tried stuff that didn't work, I'll be sure not to duplicate those experiments! ;)
Also, do you if anyone has yet tried QuickTD's idea of adapting a VNT can to be controlled by boost pressure? Thanks for your help!
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Didnt some versions of the Dodge Daytona Shelby (1990-ish) cars use a VNT turbo? VNT 20 or VNT 25 sound like they ring a bell. I highly doubt that during the few years they were made, they had any sort of computer controlled boost device. I dont have a clue how they worked, but maybe you could look up how they worked and copy the idea. :)
Just a thought, as I saw one on the way home from work today.
Brendan
84 Scirocco 8v
00 Camaro L36 M49
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I've made some GREAT progress today! No time for a very detailed update right now, but here's a pic for you guys...
(more pics plus testing results will be coming later...)
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OK, on to some more pics!
Disassembling the VNT can:
Ground / filed off the crimped-on lip off the VNT can:
(http://www.imagestation.com/picture/sraid165/padd8e2715fb622aed29229439d4b386c/f4745a07.jpg)
Here is what was inside...
(http://www.imagestation.com/picture/sraid165/paed754b506eb636c52e6642373851926/f474585b.jpg)
(http://www.imagestation.com/picture/sraid165/p5febe15728c8af32fd44a1b1bfc2153b/f4745b60.jpg)
Modified the diaphgram replacing riveted-on stud with a different one that comes out the opposite side (so diaphgragm can be flipped over...)
(http://www.imagestation.com/picture/sraid165/p4383d68c3d2ab1731d92691ad7c9ef99/f4745b06.jpg)
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Putting the VNT can back together
1/4" 6061T6 aluminum plate. Dremel-routed out a hole and then a step around the inside of the hole:
(http://www.imagestation.com/picture/sraid165/pb77275d9b02fc9dd22e85112c4001027/f474928a.jpg)
result:
(http://www.imagestation.com/picture/sraid165/pf4339a58392f73c0293f804c14978e22/f474929b.jpg)
test fitting step for proper size:
(http://www.imagestation.com/picture/sraid165/p59c5f8f4f949b9ac1f82c0763f18d609/f474927b.jpg)
drilled 8 holes where I wanted them:
(http://www.imagestation.com/picture/sraid165/p6ea5f6019217dbef706988ce25add760/f47454ca.jpg)
The half of the can with the narrower lip fits perfectly; did not need to be notched:
(http://www.imagestation.com/picture/sraid165/p61f5138f52e939a7667cacac70c7534d/f47453b4.jpg)
notched the half of the can with the wider lip to align with the holes and allow bolt heads to have more clamping surface:
(http://www.imagestation.com/picture/sraid165/pff2ef34dd364feda28644e35f5b7d37d/f4749259.jpg)
Almost done cutting out the fabricated ring piece from the plate:
(http://www.imagestation.com/picture/sraid165/pd522d55844754888e051b3eeb7b85be1/f474525a.jpg)
Just the fabricated retaining VNT can retaining ring, cut out and cleaned up:
(http://www.imagestation.com/picture/sraid165/pd0a9ec3fce4ef05f330bfc4bc7dd2637/f474515c.jpg)
Reassembled VNT can modified to actuate with boost pressure:
(http://www.imagestation.com/picture/sraid165/pa9a9b606fa57d8db9aa8a8d20b6314e8/f4744ead.jpg)
Widened out the heat shield:
(http://www.imagestation.com/picture/sraid165/pa800c5ac85452817139f38bd24156396/f4744de4.jpg)
... and all assembled!
(http://www.imagestation.com/picture/sraid165/p3b33c5ebd74b62e94954dc7cfcb6b369/f4748fcf.jpg)
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Testing...
For testing I used a brake power bleeder to build up and measure simulated boost pressure applied to the VNT controller can. Pic of the test rig:
(http://www.imagestation.com/picture/sraid165/pdcbea1c8ca488ceffec5726189f78dfe/f4744bd3.jpg)
Results:
First thing I did was pump 'er up to 25psi and see if she holds. She did! No leakage at all. The VNT can retaining ring fabrication project was a success!
Next, I went on to make several simulated boost cycles while observing changes to VNT geometry with respect to changes in the simulated boost pressure.
I found that the VNT mechanism is sticky when it initially moves toward open from fully closed position. Tapping on the turbo might be a good simulation of engine vibrations, and helps the mechanism open earlier. Without tapping, it took in one case up to 14 psi before the vanes started opening (in which case they snapped open almost all the way.) In two other trial boost build-up cycles without tapping, it took 10 and 11 psi before I observed the vanes started to open.
The results that I feel are most accurate however were from my last trial which I made while tapping the turbo (sort of jiggling the turbo on the ground). While tapping, the vanes started to open at 9 psi. After that point they opened smoothly thereafter (with no further tapping/jiggling necessary) until about 12 psi, when the rate of opening seemed to markedly slow (was almost completely open by that point though.) By 15 psi the vanes were really all the way open.
When bleeding the pressure down, the vanes started reliably closing when pressure dropped to 12.5 psi. No "stickiness" was observed on any of the pressure bleed-down cycles, and so tapping was not attempted during the bleed-down cycles. The bleed down cycles moved smoothly and evenly until they were completely closed at 6 psi.
I am pretty encouraged with these results! :D (Besides the stickiness part... because if it's too sticky, it could cause the boost pressure to spike. But if it's not too sticky, I suppose it might actually work out favorably, helping build boost pressure to full more quickly. :twisted: )
I am excited about trying this contraption out!
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By the way, DVST8R, fabricating that ring ended up taking a lot of work with my crude shop tools. I used a dremel to cut holes and machine steps for the first time with that fabrication project! I am just happy it turned out as good as it did. But next time though I think I'll send you a drawing and have your CNC mill go at it! :wink:
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I wish CNC mill, just CNC plasma and an old lathe, but they seem to get the job done :wink:
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Nice work, can't wait to read about how it runs!
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I made this (http://www.kotinet.com/matti.farm/Audi/Turbo/114-1500_img.jpg) a couple of weeks ago. Haven`t tried it yet though.
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I am excited about trying this contraption out!
I'm excited to hear the results. This is exactly what I had in mind.
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Good lord, that's an impressive progress! Nice work.
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Thanks for the compliments guys!
(http://www.kotinet.com/matti.farm/Audi/Turbo/114-1500_img.jpg)
Audi80 - wow that is impressive work as well. It looks like one of the larger VNT turbos? Can you tell us more about what you did? It looks like you used the stock VNT can as a starting point, but it looks like maybe you welded a flat piece to the half of the can that is away from the turbo. Did you do that to make it flat and allow increased travel of the flipped over diaphgram inside? Did you flip the diaphgram over inside?
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I'm almost done fabricating a stainless steel EGR block off plate (which is very carefully crafted to allow clearance of the long-runner 1.6lNA intake manifold... 8) ) There is not enough clearance for the long-runner A2 gasser intake with this manifold so now you know why the TDI guys aren't slapping those on their motors (I don't know if an A1 gasser intake would fit or not...) Also am almost done fabricating the turbo oil outlet flange (out of aluminum... waiting on some AN fittings to arrive in the mail which will either weld or screw into the flange.) Also out of thick stainless am almost done fabricating a turbine outlet flange. Man that stainless (300 series... nonmagnetic) is tough to work with. It was really challenging making the big hole in the middle. I went through quite a bunch of drill bits drilling a bunch of little holes to try and make one big hole (after toasting a hole saw.)
I tore off the passenger motor mount and the head also today. Motor mount is shot - big surprise :roll: . What really did surprise me though was how loose the timing belt was set - and that the car ran like that for so many miles (it's been years...) without self-destructing. The belt even looked to be in OK shape. I've never seen one so loose and floppy! It was so bad I could twist it 90 degrees! Whoever tensioned it did it incorrectly, turning the tensioner the wrong way (causing less belt wrap around the cam.) The tensioner bolt was on plenty tight so that wasn't the problem. There is a lot of other evidence abound of sloppy previous mechanic work... I'm finding a bunch of fasteners that are either "he-man tight", or "almost ready to rattle off" loose. I have been perplexed at this engine's smoking problem, hopefully that loose timing belt is the main culprit! I never did double check the cam timing... I did set the injection timing though (set it off the crank TDC mark.)
Oh by the way also once I got the head off I looked at the pistons and found that they are the largest overbore (77.5mm) Nice to have a little extra displacement. :)
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Tip for SS and SS not just 304-309-316 ect... Go SLOW and keep it COOL as soon as it heats up it goes redicoulsly hard, and eats drill bits, hole saws ect... If your welding it (I know you don't have a TIG setup) Stick is probably the next easiest for 300's SS, Then either oxy-fuel, or Wire.
Sounds like some good progress!
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Man does that stuff get hard when it work hardens! I did not realize the hardening was triggered by heat. I just have a little bit of crud around the inside edge of the turbine flange left to grind off and then it will be done. I am happy to have gotten that far.
I am thinking about going 2.5" stainless downpipe tubing, but with that size it looks like I would have to dent the tubing to be able to access two of the nuts. The exducer bore of this turbo, after the machined-in step, is only 1 3/4"! This is a small turbo, at least compared to stock 1.6lTD units. :lol:
This stainless tubing I got is grade 409 I'm pretty sure. I have not welded it before, but I can competently oxy-weld 304 (I made an entire exhaust system of my Rabbit that way.) Any tips on welding the 400 series stainless?
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Does anyone here know if aluminum AN nipples can be welded? (...to 6061 aluminum)
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Does anyone here know if aluminum AN nipples can be welded? (...to 6061 aluminum)
I believe so. A racer friend of mine attached AN fittings to an oil tank (Porsche) and to some oil cooler cores to make them AN compatible. Obviously, the right equipment, settings and a bit of know-how are necessary...
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400's, really aren't that much differnt as far as welding goes, I'm sure that you wont have a problem.
As far as the Al 6000's weld just fine as long as there not heat treated IE. T-6 it is still possible to weld those except that you loose the heat treatment in the process. If it is just normal 6061, no problem, but you will loose most of the cool anaditzaiton (sp?) coloring, but other then that it will be just fine. The Key to welding aluminum is to have it CLEAN! with chemicals and brushed. Also rember that the oxide that forms over Al. doesnt melt till like 3000ish degrees and Al melts at like 1800ish, so the puddle doesnt last long b4 it melts through! **As it starts to turn dull from shinny you can start to add filler even though it doesnt look like a puddle in most instance's** make a few practice welds on similar sized scrap first. Like anything it just takes a little practice. :wink:
Hope this helps some. You can weld Al with oxy-fuel jsut have to find some flux, (i heard that you can get flux filled tig rods for welding realy poor Al. those might work for you) Try BOC , or Air Liquide for other flux's, some body will have it.
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Does anyone here know if aluminum AN nipples can be welded? (...to 6061 aluminum)
Quality aluminum fittings and hardware are often made from 2024 aluminum. It is quite hard and cuts very freely on high speed lathes without the gummyness inherent to softer alloys like 6061. 2024 (or 7075 or any other high strength alloy) is not very weldable, it tends to crack. Best to weld on threaded bungs and then screw the fittings into those or thread the adaptor plates themselves
Another tip for stainless, use lots of pressure and use sharp tools. One revolution of "rubbing" with a dull drill will form an impenetrable skin... I find the CNC mill does an excellent job. It is absolutely merciless. It never gets tired and backs off like humans do...
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(http://www.imagestation.com/picture/sraid165/p3b33c5ebd74b62e94954dc7cfcb6b369/f4748fcf.jpg)
That's real pretty. I'm impressed.
Do you have it on the car yet?
-Dave
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MrDave: Nope. Still fitting and fabrication... this is a big job, I am doing a lot of stuff all at once to this car. I am making great progress though. I got the motor mount hacksawed out and a new one pressed in, and motor mount re-installed in the car along with the other injection pump mounting brackets. And got the whole passenger side of the motor and brackets cleaned up (had a thick grease cake, leaking valve cover gasket. :roll:)
On the turbo I had to remove the compressor housing and sand down the compressor inlet nipple, because it was some weird metric size, and was 1/32-1/16 or so too large for the 1 3/4" aeroduct I got to slip over. Aeroduct doesn't conform by expanding in diameter by very much! I also sanded and polished the turbo air inlet so it has a nice and smooth bellmouth type opening. That is the smallest restriction point in the intake tract where there is only atmospheric pressure to get it though.
Others: I will probably not attempt this aluminum welding with my oxy-fuel rig myself... But that's great to know it is weldable. I will probably take it somethere to have it done. I do have some aluminum welding flux, but when I tried it previously I did not get good results. I need more practice before I can weld aluminum, which I don't have time to do right now. I can do stainless and mild steel great though. My brother's in town now and I just last night helped him welding a blow off valve flange onto a boost tube for his mitsubishi eclipse. He just got back from army training where he's a metal worker, and just got certified in welding. But I was the one who ended up doing the welding! I am more experienced with and know my oxy-fuel welding rig better. They don't teach the use of antiquated welding tools in welder's school I guess. :lol: But I enjoy playing with molten metal whenever I get a chance.
Oh... I will be welding a (steel) AN nipple onto the oil pan with my oxy-fuel rig. That should be fun.
I have another fabrication job for this project coming up... modifying the NA diesel intake manifold for forced induction. Can anyone help me with a plenum volume calculation of the NA intake manifold and tell me if it's adequate, too much, or not enough? I have not done that yet but I probably will need to before I can finish it. I also have a couple decisions to make for manifold boost pressure adaptation - to bolt on an aluminum plate to the front with some sort of gasket, or to weld? And other question is where to put the air inlet nipple - front, underneath, or one of the sides. I think I will get the head back on and hang the manifolds on the car seeing where things sit to figure that out. If I want to get this done quicker, I could bolt on the turbo manifold temporarily and save the long-runner NA manifold project for later. That might make some sense...
I'll post another round of pics shortly.
Oh by the way Quick, Thanks for chiming in with your experienced tips of stainless working. I am sure I was doing it very very wrong. :o Actually the cobalt twist drills were the only thing I was able to get through that stainless with any reasonable speed.
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all of that oxy-fuel welding will make you a quick learner on tig! same basic priciples just heats quicker and more control over the heat.
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>>I have another fabrication job for this project coming up... modifying the NA diesel intake manifold for forced induction.
Jake...
Have you considered possibly using an A1 or A2 gas intake for that purpose? Are you running an intercooler on that one? (this is your Dad's, right?)
I'm thinking you could remove the throttle body and then make a plate to attach to whatever tubing you'd like for either the turbo to intake pipes or intercooler to intake pipes. If you use the A1 style (I've got a few by the way) you might actually end up with a better location for the intake opening.
Here's a pic of a CIS rabbit type intake (not mine). You'd have some ports and get/make a digifant cold start injector hole block plate, but I think it might work well for you....
(http://www.hostdub.com/albums/veeman_album02/CIS_intake.jpg) (http://www.hostdub.com/veeman_album02:CIS_intake)
Might be easier than welding up that diesel box and trying to pressurize that huge box. I wonder if it would clear that turbo setup back there?
I researched intakes quite a bit when doing my gas FSP car (soon going to standalone) and some argue that the A2 intake with its longer, tapered runners provides some torque benefits. For right now, however, I'll be using a G60 intake on mine. It opens to the driver's side, has bigger runners and less ports for me to block off for the EFI system.
Let me know and I can get you pics if you like...
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Can anyone help me with a plenum volume calculation of the NA intake manifold and tell me if it's adequate, too much, or not enough?
Try this:
http://www.grapeaperacing.com/GrapeApeRacing/tech/inductionsystems.pdf
Some good info regarding intake tuning.
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Veeman - I plan on at least initially to put the motor back together without intercooling. Although eventually we might put one on there, I plan instead to fuel conservatively and monitor EGTs to start. Adding an intercooler and associated boost tubes is too big of a chunk to bite off all at once.
Also as mentioned previously, I have an A2 gasser long-runner intake, but I found that test fitting it to a junk head I've got in the garage that it does not clear the TDI manifold. The problem is that the TDI exhaust manifold has an EGR port and flange that sticks up way too far - it's not even close.
The runner lengths of the NA Diesel manifold are identical as far as I can tell to the A2 gasser intake. The NA Diesel intake manifold is close - but I can and I did design the EGR block off plate and fastening system specifically so that the NA Diesel manifold just fits.
I have not yet measured the plenum volume of the NA Diesel manifold, but just from eyeballing it, and also knowing it was originally designed for the naturally aspirated motor (which has no different plenum requirements from a turbo motor unless you subscribe to the "minimal plenum for turbo to reduce boost lag" school of thought, which I am not sold on), it is probably approximately the right size. I know that it's runners are a good design with very smooth radius bends and specially shaped "D" runners to minimize air resistance through the bends. The runner lengths are also designed to fit the working RPM range of the 1.6l diesel (the heating of the intake air charge from the turbo will effect the tuned frequencies somewhat, but based on my calculations the impact is small and acceptable, at least for an intercooled motor.) If I want a specicic plenum volume with the 1.6lNA manifold, I can do it by varying where I decide to weld the front plenum wall to the manifold.
I don't have an A1 gasser long-runner intake to try fitting up to the test head with TDI VNT installed, so I'm not sure if that would clear or not.
My latest thoughts are that initially I will bolt up the stock TD intake manifold to get this thing back up and running and minimize downtime. Then at a later point as a separate project and experiment, I can fiddle with adapting and installing the NA Diesel intake manifold. That way I will be able to test the difference it makes to the HP and TQ vs RPM curve real scientific-like, which I've been wanting to see done for a long time! :wink:
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QuickTD: I guess what I meant to ask was has anyone measured the plenum volume already on a 1.6lNA manifold?
(Alternatively, I guess I could do a ballpark estimation myself pretty easily by measuring length, width, and height and then multiplying. ;) )
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Or, for more precision, just plug the ports and fill the thing with water. Dump out and measure the volume.
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all of that oxy-fuel welding will make you a quick learner on tig! same basic priciples just heats quicker and more control over the heat.
Yeah... if I only had $1400 burning a hole in my pocket to buy a TIG setup! :o :wink:
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Hey guys - I can weld aluminum with my oxy-acetylene rig! The trick I needed was using water instead of alcohol to mix the flux... check out these results... My first successful aluminum welding project (it's an oil return fitting for the TDI VNT):
(http://www.imagestation.com/picture/sraid165/p24a6fe527dab0cd4ba6abccd168fd389/f462d171.jpg)
After being cleaned up with the file (ready to be bolted on!)
(http://www.imagestation.com/picture/sraid165/p0735b832de4e2c095ebf37b5df604e16/f462d1aa.jpg)
It is so cool to see how the weld bead is solid aluminum... now I am re-thinking doing the long-runner intake. In fact, I already started removing unnecessary metal from the 1.6lNA intake manifold:
(http://www.imagestation.com/picture/sraid165/pf712a766f8aec57b5c7f0f005bda8f5c/f462d55e.jpg)
Plenum size is indeed large. I estimate based on measuring the dimensions a displacement of about 170 cubic inches. According to the grape ape racing plenum calculator (50-60% engine displacement plus 30% if boost is desired at "low" RPM of 2500-3500 RPM), the optimal plenum size would be about 70 cubic inches. So I am over twice that with the 1.6lNA manifold if I were to just weld a plate to the outside edges of it. On the other hand, the plenum is an air capacitor... and I don't see much problem with having a little extra. That VNT turbo should fill it up quite quickly I'd bet. When I added a quite large Audi5000 intercooler and 2" to 2.25" boost tubing runs to my 1.6lTD, I didn't notice much significant increase in turbo lag. So my intuition is telling me that a little extra plenum wouldn't hurt. Grape ape racing states "The good thing about plenum sizing is that there is a pretty wide range that it can be and still be effective" I'm wondering if I should weld the 1.6lNA manifold up at approx 170 cubic inch plenum volume, hacksaw the thing down to reduce the plenum volume, or try and locate an A1 gasser intake to see if it fits... what do you guys think.
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I think with your new found Al skills, you can pretty much do any type of intake you choose. Nice looking oxy-fuel weld! I think a custom Al intake manifold is in order to showcase those skills. Well seeings how the VNT already will push the low end torque way up, I think that the plenum should be tuned more for the mid to high rpm range, in what ever shape that takes.
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Nice job on the welds... looks fantastic. A friend of mine on the Audi lists started making his own intake manifold and he used the stock runners and connected them to an aluminum pipe / tube around three inches in diameter.
You could simply saw off the "box" part of an NA manifold and start from there. For him, he would have had to attach a specific throttle body type adapter to one end, but you could do anything you wanted.
Using the pipe method, you could do the calculations, mock it all up with PVC to make sure everything clears, then set out to weld it all together. I can find pics if you want.
...Or if you like, the offer still stands to check out one of my A1 gasser intakes.
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Just wanted to update you guys... the exhaust manifold/turbo is all ready to install with the following modifications: VNT boost pressure control conversion, custom AN-10 aluminum oil return fitting fabricated and installed, compressor inlet sanded down on the outside to take 1.5" ID aeroduct, and inlet bell-mouth smoothed and polished. A pre-turbine thermocouple hole was drilled and tapped and the thermocouple installed (will post pics later), EGR block-off plate fabricated and installed with special countersunk hardware to maximize clearance with long-runner NA diesel intake, and intake to exhaust manifold support bracket fabricated (to structurally tie together intake manifold to exhaust manifold). Stainless downpipe flange fabrication is also completed and fits nicely to the turbine outlet and fasteners (just needs filing flat on one side.)
The head is all cleaned up ready to go, and it came out flatter than any used diesel head I've laid a straightedge across! While the specs call for not being able to slip a 5 thousands feeler under it anywhere on the combustion chamber sealing surfaces, I could only slip a 1.5 thousandth feeler gauge under when the straigtedge was laid over the prechamber inserts! No warpage here (at all.)
I found evidence of where the head gasket leak had happened too. Like other overheated IDI VW headgasket failures I have observed, it was a leak between coolant port and combustion chamber on the back side (opposite of prechambers.) The metal fire ring around the combustion chamber was actually eroded and pitted all the way around in the cylinder that had the leak, and the fire ring was cracked near the leak also. I think the degradation of the fire ring was from hot exhaust gasses and/or coolant slipping by it and eating away at it. I had not seen a cracked fire ring before. But the good thing is the overheat was caught early enough that the head was not permanently warped.
The engine besides needing head bolt holes and it's deck prepped (might clean the piston tops up a little) and grease cake cleaned off the back side of the block, is ready for the head to be installed, with all four motor mounts replaced with brand new and also now sports the factory air-water oil cooler.
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Are you going to stud the block and use a 1.9 HG?
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Nope - going to run just a standard fiber head gasket (this is a solid lifter head, so not that easy to adapt a 1.9 head gasket... due to the difference in water jacket / oil return) I do have some used raceware head studs sitting around however which I'll throw in there.
I cleaned the deck and measured piston projections today and found that the 3-notcher that I bought (same as came off the car) was not the correct thickness! The piston projections call for a 2 notcher, although it was very close to a 1 notcher. The 3 notch is definitely incorrect and is too thick (must have been a sloppy mechanic who worked on this...) Tomorrow I'll need to track down a 2 notcher. I'm basically ready to install the head and the manifolds!
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Pics of the EGR block off plate and the manifold to manifold support bracket:
You can see I beveled the edge of the stainless block off plate as well as replaced one of the original studs and nuts with a countersunk screw in order to gain more clearance with the long-runner NA Diesel intake manifold:
(http://www.imagestation.com/picture/sraid166/p5ee85d6c72a300b184ab321f2a8a5c09/f4509daa.jpg)
(http://www.imagestation.com/picture/sraid166/p0d9195d48c3c97546f6077689734ff44/f4509d86.jpg)
It's a tight fit, but it works!
(http://www.imagestation.com/picture/sraid166/p6294c0db5623d7e34fc2d2c20860fdf5/f4509db3.jpg)
(http://www.imagestation.com/picture/sraid166/pfb0198ac3c5edacef6df6608c27140aa/f4509dce.jpg)
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And some pics of the pyrometer thermocouple installation:
drilling the hole:
(http://www.imagestation.com/picture/sraid166/p550ee644a42a3484c5f8064c04f2d810/f4509d95.jpg)
(http://www.imagestation.com/picture/sraid166/pe21db5f32480a39227e79bf85dcd1958/f4509da2.jpg)
I rigged up the shop vacuum to blow the chips away from the turbine. I tried an interesting test which was to move the variable vanes when the vacuum was blowing and see what difference it made. The vacuum noticeably loaded and airflow significantly increased when I opened the vanes!
Completed thermocouple install:
(http://www.imagestation.com/picture/sraid166/p398a69618afc7def4b17f71e82962db6/f4509dba.jpg)
By the way, don't worry, that head pictured above is a junk head I just use for testing the fit of manifolds. Here is the good head after being cleaned up: (flat as a board!)
(http://www.imagestation.com/picture/sraid166/p6d329a128879517e36d4efddba78aada/f4509d8c.jpg)
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Nice! That looks sweet. I'm jealous! :)
Your craftmanship is A-1.
I just realized that there are a lot of talented S.O.B.'s on this list- makes me feel glad to be a part of it!
So you may be ready to fire it up this weekend? :)
Brendan
84 Scirocco 8v
00 Camaro L36 M49
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Thanks!
Today I got the head on with a 2-notcher head gasket I picked up this morning. I also cleaned up a 1.6lTD injection pump and bolted it up and installed the toothed pulley and timing belt, which still needs to be tensioned and cam pulley set, but the head is torqued to the block and there are a bunch of pieces ready to be installed which should all go quickly, including bolting up the turbo / exhaust manifold. :D
I won't be able to work on it again until probably sunday. After I get the turbo /exhaust manifold is bolted up, I've still got to sort out how to route the boost tube to the intake, and whether I'll install the short runner or the long runner intake manifold to start with. Also need to determine where to put the air cleaner and how to plumb it to the turbo (so, may need to fabricate a custom air tubing adapter or two...) and also will need to install the turbo oil supply line (hopefully can just bend the stock 1.6lTD oil supply line) and make up an aeroquip line for turbo oil return (including welding an AN fitting to the oil pan.) I'll also need to fabricate a tubular exhaust downpipe with some sort of flex joint (maybe salvaging the old flex joint that was on the exhaust system previously) and decide if I want to connect it all the way to the rest of the exhaust system myself (which is rearwards of the shifter but before the fuel tank) - in which case I'll probably need more tubing and bends, or whether I'll just drive it to a muffler shop to have them put the exhaust system together. So it will hopefully be sometime next week when I'll be ready to fire her up.
Edit: pic of raceware head studs installed along with head gasket (coated with copper spray-a-gasket):
(http://www.imagestation.com/picture/sraid167/pbe085e72eabebbc1621eb4bdd6e6b59a/f4456423.jpg)
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Thanks!
I'll also need to fabricate a tubular exhaust downpipe with some sort of flex joint (maybe salvaging the old flex joint that was on the exhaust system previously) .
If you guys need any stainless mandrel tubing or flex couplers..
one of my buddies owns www.ghlmotorsports.com he sends me whatever I need tubing wise and flex coupler wise.. at a MUCH lower price than burns stainless or other companies..
let me know
later
mike
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Today I got the camshaft and the injection pump timed. I found I was able to prime the injection pump (which was previously completely drained out) by using a squeeze bulb to suck air out of the fuel return line.
With the turbo/exhaust manifold loosely installed, I bent the 1.6lTD oil supply line to make it fit with the TDI VNT turbo. I am pleased with the result:
(http://www.imagestation.com/picture/sraid167/pc98968edfcd02b0ac8d36987ac07b7bd/f4456775.jpg)
(http://www.imagestation.com/picture/sraid167/p51b95b2753e3e8b25111bc4708087676/f4456733.jpg)
I will soon be fabricating a custom downpipe. The downpipe will need to make a pretty tight bend down and toward the rear of the car in order to clear the nearby shift linkage:
(view from below, looking up:)
(http://www.imagestation.com/picture/sraid167/p9fbc8a9d2e66ce661c9a6724bc9905c6/f4456754.jpg)
Also I've got the oil pan off now and will be welding a fitting to it for the turbo oil return. It will be going back on with a windage tray oil pan gasket! :P
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Freakin' awesome, Jake! :D
Just one question, tho...how do you plan to do this?
Just wanted to update you guys... the exhaust manifold/turbo is all ready to install with the following modifications: VNT boost pressure control conversion [emphasis added]
I couldn't find any details. Can you point me to where you covered this or expand on your plan?
Thanks!
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Thanks for the encouragement Stan! Look earlier in this "mega thread" to read about my VNT controller boost pressure conversion. Specifically, here:
http://www.vwdiesel.net/phpBB/viewtopic.php?t=1306&postdays=0&postorder=asc&start=26
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Jake, are you timing the cam any differently from stock? Retarding it by a few degrees will make a noticeable difference in the top-end.
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Nope. I set the cam timing right at the TDC mark, although when I was checking piston projection I found the factory TDC mark on the flywheel was off by .5 degrees (can't remember which direction, but it was a small enough variance I figured that it shouldn't matter.)
This is a daily driver application, so I opted to not compromise piston-valve clearance to bias the powerband either one way (higher RPMs) or towards lower RPMs. Knowing my dad, he would probably prefer a broader powerband over more horsepower anyway, and it just has a 4-speed transmission (although the ratios of this "3+E" style 4-speed, with a .70 fourth gear IIRC, are practically as good for highway cruising as any five speed - and with less "gear rowing" required than a five speed, should be a GREAT setup for a torquey TD daily driver.)
I also attempted to set injection pump timing as closely as I reasonably could to the stock specs (1.00mm.) After setting the timing and torquing the pump mounting bolts, I re-zero'ed the dial indicator and checked the timing. Came out to 1.01mm, a variance of only .01mm... (which seemed to be a difference of only a fraction of a crank degree.)
I found that the cold start lever was *really* hard to move without any fuel being in the pump! :? I have my fingers crossed that it gets easier after the engine is run for a whileand the pump has time to purge all the air out of the cold start piston cavities. If it doesn't get better, I will probably replace the cold start cable at the least (It's housing was looking kind of old and cracked...)
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I will soon be fabricating a custom downpipe. The downpipe will need to make a pretty tight bend down and toward the rear of the car in order to clear the nearby shift linkage:
(view from below, looking up:)
(http://www.imagestation.com/picture/sraid167/p9fbc8a9d2e66ce661c9a6724bc9905c6/f4456754.jpg)
On my TDI rabbit, I ended up putting a 1" extension onto the shifter, to elevate the swing arm, in order to clear the elbow off of the turbo.
On a, uh, let's say, enthusiastic shift, if you listen carefully, you can hear the metallic 'ting' of the shifter hitting the downpipe.
I'm also running heim joints for the shifter linkage, with a nut welded into hole on the end of the swing arm for a tad more clearance.
The TDI is a taller block than your 1.6, so you'll need a real tight elbow, and you may need to use a longer extension on the shifter piece.
Maybe you should just switch to a cable shift tranny...
-Dave
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I've found that it is a much better method to make the linkage shorter by amplifying the lever of the shifter extending under the car near the driver, rather than making the relay lever arm longer. IME, it amplified the "slop" much more when the relay lever arm is lengthened, as well as reduces the inertia of the linkage, increasing "notchiness". For more thoughts on this topic, check out my review of the EMPI Rabbit shifter, which I installed in this car:
http://www.vwdiesel.net/phpBB/viewtopic.php?t=1146
I've already been completely through the linkage of this car, and it's totally awesome, best shifting A1 I've ever driven. Even better than my GTD autocrosser with trick heim fittings! I am amazed how easy it is to grab any gear, down to 1st.
Because I would rather not alter the geometry or throw of stock relay lever arm, I am planning on fabricating a very tight angled downpipe if needbe. ;)
I also don't think there will be a performance penalty from a very tight angle of tubing initially coming out of the turbine housing. I understand in that area the flow frequently is in a spiraling vortex, and the reason manufacturers often have an abrupt step macined into the exducer bore of turbos is to break up this vortex. Since laminar flow is already being broken as the air comes out of the exducer here, I don't think putting sharp kink in the passage right out of the turbine here will add a restriction. Hugh Mackinne's "turbochargers" even shows a banjo-like tubing shape coming out of the turbo used in a really tight clearance application, and says it flows great. I am going to see if I can make 2.5" tubing fit though! 8)
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... rather than making the relay lever arm longer.
Uh, never said anything about making the relay lever arm longer.
Just located it higher on the vertical axis, to clear the downpipe as it swings.
-Dave
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Ah, gotcha. I think that on mine, the end of the relay lever is about as high as the center of the turbine outlet.
Edit: here's another pic of this area...
(http://www.imagestation.com/picture/sraid167/p356590c0639e64ad72ccf053c41c31c5/f4456798.jpg)
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Here (http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=1327&prmenbr=361) they have a 2.5" diameter pipe mandrel bent to a 3.5" radius.
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I have a stainless 4" center line radius 2.5" U-bend I will see first if I can make work. If I need tighter, I actually do have an aluminized 3" center line radius 2.5" U-bend, although I'd prefer using stainless instead.
If I wanted a really tight bend, I could opt for a "tube doughnut", where the center line radius is equal to the tube diameter! Anyone use one of those before? They look pretty intriguing...
(http://www.hrpworld.com/client_images/ecommerce/client_39/products/1228_1.jpg)
(Not exactly cheap though...
http://www.hrpworld.com/index.cfm?form_prod_id=198,55,363_1228&action=product )
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(http://gli.trouvist.com/other/f4456798.jpg)
I extended this shaft, and moved the swing arm up enough to clear. Remember, you could always modify the shifter rod on the end of the swing arm to remedy the change in the Vertical position.
Also, and I must stress this, remember the downpipe bolts when fabbing your dp. What kind of wrench do you want to use? You could make a very short elbow, but find yourself not be able put one of the nuts on.
Or, find yourself using an open ended wrench and just having the rusted nut strip when you're trying to disassemble it someday.
Cable shift, my friend. Think about it.
Plus, maybe you could install one of these:
(http://www.trickstarsbmx.com/images/tom/DSC00349.jpg)
as an aside, I'm super impressed how clean your engine bay is. If it was in focus, I'm sure I could read the part number from the shifter bracket.
-Dave
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Okay Dave, ya gotta tell us...what is that thang? ;)
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Thanks for the encouragement Stan! Look earlier in this "mega thread" to read about my VNT controller boost pressure conversion. Specifically, here:
Thanks Jake! Now I understand the mechanism for controlling it, but still don't see any reference to a controller. After all, your A1 doesn't have a TDI's ECU. Am I missing something here? :oops:
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Okay Dave, ya gotta tell us...what is that thang? ;)
VWMS shifter.
link (http://forums.vwvortex.com/zerothread?id=1800921)
(http://clam.rutgers.edu/~dreadsct/rallypics/golfIII/interior.JPG)
-Dave
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In theory Stan, this will work out just like the wastegate of a 1.6lTD... Nice and low tech! :P
I am hoping that the flipped-over spring in the VNT can will hopefully be all of the vane controller that I am going to need! I will likely just hook up a small line from the intake manifold directly to the VNT can. As boost pressure rises, the VNT can will open the vanes, and hopefully the system will reach a stable equilibrium boost pressure, ideally getting there quickly and smoothly. Sure it won't be capable of doing fancy stuff the TDI computer does like opening the vanes at idle to improve idling fuel economy, or reducing boost pressure at altitude to keep the turbocharger 'safe', or going into a "limp home" mode. (But also, these are all kind of lame features anyway, right? :wink:)
Expected boost pressure equilibrium is somewhere over 9psi (I'd guess a little bit)... but how much exactly it will be or how well it will work, can't really say until I complete the install and get it all up and running in the car. I just hope the boost doesn't creep or spike too badly, or go "buckin' bronco" on me! :lol:
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Alright...thanks for the great explanation, Jake! Like everybody else, I can hardly wait to see how it works out. :D
Thanks Dave...that shifter is the shiznitz! :twisted:
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This is turning out to be a really cool thread
oh and...
HURRY UP ALREADY!
:lol:
I'm excited to hear the results of your efforts.
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I just hope the boost doesn't creep or spike too badly, or go "buckin' bronco" on me!
If the "buckin' bronco" scenario does occur it should be a fairly simple matter to "dampen" the response a little bit by restricting the flow through the wastegate hose. If the response is too slow and you get bad spikes, I'm not sure what to do... :?
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I am steadily inching my way towards project completion here... Today I got the oil return fitted and welded into the oil pan. I recessed the fitting back into the pan as far as practical (welding it to the inside of the pan rather than the outside) so the oil drain line would get a little more clearance to the driveaxle. I also wanted it as high as possible without interfering with the pan lip. But when I welded the fitting with the oxy-acetylene torch so close to the pan sealing surface, the sealing surface near the fitting warped! So then I spent a few hours futzing around with the oil pan making special braces so I could hammer the warped surface back to flat without damaging the threads of the AN fitting. It was a lot of work, but I avoided damaging the threads and I think the pan is now going to seal up great. I think I know now why VW made their factory TD oil pans with the drain fittings spaced so far away from the pan sealing surface now! :?
Anyway, the oil pan is all cleaned up now and has a coat of paint on it. It should be dry tomorrow and ready to bolt up, then I can finish making the oil drain line and move on to some downpipe fabrication!
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keep us posted!
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Snapped a few pictures today...
oil pan with AN fitting installed:
(http://www.imagestation.com/picture/sraid167/p29bff4403391437615527cd5103bd548/f43b3f05.jpg)
here's how it looks with the windage tray 8)
(http://www.imagestation.com/picture/sraid167/p514f3d3ae6f267ebc13b4aebd06d6c3d/f43b3e21.jpg)
Made up an Aeroquip -10 braided stainless hose with straight and 90 degree ends:
(http://www.imagestation.com/picture/sraid167/pccd03a05bec2891a31a86bfda5c0821e/f43b415a.jpg)
The turbo oil system is ready to flow!
(http://www.imagestation.com/picture/sraid167/p30d8776730b0b88dfdad724b9d68badb/f43b43f5.jpg)
I also relocated the fuel filter inside the passenger fender (essentially copied the setup off my GTD.) Main things left to tackle are the downpipe, air filter, and boost tube.
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I also loosely installed the long-runner NA Diesel intake in the engine bay to see how it fits with the TDI exhaust manifold / variable-vane turbo:
(http://www.imagestation.com/picture/sraid167/p9052b43b045a973142ffb30b04b1d44a/f43b43bd.jpg)
(http://www.imagestation.com/picture/sraid167/p9537e65144d5d43f06b271c4a9d1c1d5/f43b43d6.jpg)
(http://www.imagestation.com/picture/sraid167/pb496ce7281fd86219df4388bfecb04e6/f43b440c.jpg)
(http://www.imagestation.com/picture/sraid167/pd9dd911005e73c28ad5f27c216b3d16d/f43b443b.jpg)
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Nice work!
This is looking great, I can't see why it would not work very well.
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Thanks! I am getting close... still need to do some air intake and exhaust tubing and duct work (I've sort of been saving that for last), but just about everything else is ready to fire up now. The fuel system is all ready to go, even primed it including the new relocated fuel filter. All coolant lines are installed, coolant is filled, and I even pressure tested the system to 15 psi - with no leaks. Fresh oil is filled in the sump and the system has been pressurized / primed with a techtonics hand-drill oil pump adapter. All the manifolds are torqued up, with the 1.6lTD intake manifold being installed. The electrical stuff is all hooked up (except wiring for the new gauges which I need to route past the firewall.)
You guys won't believe how much room is behind the engine! The TDI turbo really "hides out" down low underneath the intake manifold. Another cool feature of this setup is ALL the TDI turbo's exhaust manifold fasteners were directly accessible... can easily check the torque, no unbolting the turbo from the exhast manifold first. Nothing is in the way!
I have not tried totally priming the fuel system like this before, but I think it may have worked really well. It will be interesting to see how long it takes cranking the motor before it starts. I fitted a squeeze bulb to the fuel return and pumped away until fuel filled the new fuel filter, entered the pump, came through the return line (could really feel the resistance increase when the fuel starts passing through the tiny hole in the fuel return banjo) until it leaked out the outlet end of the squeeze bulb. Then I hooked the return line back up to the tank fitting.
(http://www.imagestation.com/picture/sraid167/pc2643989e586f6da0e0d3261d76369ff/f43849ff.jpg)
I also replaced the alternator pulley. I lucked out in that an old 40mm wrench I had kept in the bicycle toolbox fit the outer alternator pulley nut perfectly! Combined with a standard big socket (can't remember what size it was... but probably around 3/4") fit the inner nut pretty well. I was able to change the pulley with the alternator still installed in the car:
(http://www.imagestation.com/picture/sraid167/p40196c5671aa546743e54b092b4676eb/f4384957.jpg)
Here is a comparison of the old versus new pulleys. The old one is definitely worn compard to the new one. I believe that it no longer had the proper conical profile that matches the v-belt. I believe as a result of the worn pulley, the belt couldn't get good traction and belt life was short. (Close-up of the pulley profiles - old pulley on right, new pulley on left:)
(http://www.imagestation.com/picture/sraid167/pf147540b39154a8847944a38fe3034cb/f438487a.jpg)
Still trying to source a proper TD harmonic balancer.
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A new pulley! Where did you find it and what is the part #? I desperately need one as my old pulley was ripping the cogs off my belts after 20K km. I just got one put on by a wrecker and I fear that it is going to do the same thing...in 10K km. Could you be so kind as to take a photo with a 13 mm (1/2 inch) belt sitting in the new pulley? My belts are always sticking out further than the edge of the pulley for some reason. I have a trunk full of spare belts with frayed edges and missing cogs. :shock:
Thanks, Steve
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It seems all of these old bosch alternators with the sheetmetal pulleys have this same problem. The sheetmetal pulleys just don't hold up forever. Even rebuilt alternators usually don't have new pulleys and so the problem is not fixed with them.
I got this pulley kit from the VW dealer. The VW part number for the pulley kit is: 049 903 119 L. The cost was about $30. I have found it listed aftermarket for a little bit cheaper, but not much. For example, GPR parts lists it for $25(US):
(http://img.eautopartscatalog.com/live/F405014916BOS.JPG)
I know that this pulley kit fits the Bosch alternator that came on '81-'84 Rabbit Diesels, but I don't know what else.
If I work on the car tomorrow, sure I will take a picture of how the v-belt sits in the pulley for you!
I found an old picture of the carnage that happened when the alternator belt broke on my GTD and got wound around the plastic timing belt cover, burned through it, and broke the timing belt. It's a really ugly picture. And I have a bent valve and broken cam lobe sitting on my mantle as a reminder of that incident. You really don't want that happening to your car!
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(http://www.imagestation.com/picture/sraid167/p40196c5671aa546743e54b092b4676eb/f4384957.jpg)
That 40mm wrench is a head set wrench for a bicycle I am just about positive, if anyone else needs to find one...
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My VW dealer wants 70 to 120CDN for a pulley and what's worse is that they don't know which one to order. They don't know what output my alternator is and it has been converted from an AC alternator to a single belt alternator. I'll have to find a Bosch dealer in town.
Steve
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Pic for steve:
(http://www.imagestation.com/picture/sraid167/p0b8e0ad2730b3a1f763d411d30d43e51/f435d8ad.jpg)
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Thanks! I must be using the wrong belt, my 13 mm belt sticks out further on the alternator but looks perfect on the crank and waterpump. If I were to use that belt it would look okay on the alternator but be deep in the other two pulleys. :?
Steve
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An update: Have done some fabrication here and there since my last post (air intake was a big bear of a job), and am now pretty much done with everything except for the exhaust system. I ran the engine through its first heat cycle today on it's new head gasket and VNT turbo. (I Dddn't drive it - just ran the engine without any load in the garage until it reached full temperature, then shut it off, and re-torqued the head gasket.)
During the heat cycle, I blipped the throttle a few times to see if the VNT turbo made the boost gauge move. With only light throttle blips and keeping the RPMs low (didn't want to stress the headgasket on it's first heat cycle), I was able to get 1-2 psi pretty easily! :) I found after it warmed up that it put out .2 psi continuously at idle! I am very impressed with the quick spooling action of the VNT turbo, and can't wait to get the exhaust finished so I can see how it drives. 8)
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You know you juste gave me a real stupid idea :)
VNT-15 on the 3A (2L 8v Short bloc from late 80s Audi) I'm rebuilding for the cab :)
I'd keep the linear torque curve those 8v have; hello low torque TQ and HP :)
Still the VNT-15 on a TD is great :)
way more low end torque :)
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You'll have to set the VNT actuator rod SEVERAL turns in the negative to prevent huge boost spikes when mated to a gasser...
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That alternator pulley will also fit all the way up to a 91 Jetta. The parts guys messed up and ordered me the wrong pulley (the one you have) and it looks like it would fit perfectly for the non-A/C alternator. Unfortunately I have AC.
Did I mention how much the AC/Alt setup sucks?
Ray <-- wishing I could find a non-AC alt bracket
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Anyone want to host a video taken during the first heat cycle? [Edit: Blades should be hosting these shortly... thanks Blades!]
3MB, .WMV format, 16VNTD.wmv
I also have a 750KB .WMV close up of the alternator belt, for you guys wanting to see how it runs through a good pulley, alt_belt.wmv
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Links don't work..
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Looks like the yahoo briefcase links broke for whatever reason... perhaps it is not intended for public sharing.
Anyone want to host these videos? If so, I can e-mail them to you. I am out of server space necessary to do this myself.
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fspGTD: email me the video, I'll host them
webmaster _AT_ poissant _DOT_ org
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1.6TD with VNT-15
(right-click, SAVE AS)
http://www.boucanne.com/per_images/video/16VNTD.wmv
Alternator pulley.
http://www.boucanne.com/per_images/video/alt_belt.wmv
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That's a VERY clean running alt belt.
Did you get a fresh crank pulley too or no?
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Nope... crank pulley / TD harmonic balancer is used, probably with lots of miles also. As they seem to be cut from billet steel though and also have a pretty large diameter with lots of belt wrap, they don't seem to wear very quickly. Water pump pulley is also just "good used" (I did pick the best looking one I had out of two available though.)
Although not evident in the video, I actually found there was some belt vibration up and down that was visible when viewed more from the side. But I'm pleased with how the belt looks going through the new alternator pulley. Also before the video, I added an extra shim to space the alternator pulley out a little bit to bring it into better alignment with the crank and water pump pulleys. I don't know why it wasn't aligned to begin with. :?
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Rackley: According to ETKA, a '91 Jetta Diesel with AC should have a 90 AMP Bosch alternator, and it takes pulley having part number 035 903 119. www.worldimpex.com sells it for $45 US.
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Looks good! I do not get that close to my belt when it's moving because all of my old ones are missing pieces of the sides or half of the cogs. :( I ordered a couple of those Bosch pulleys locally and I'm told they are only 15 bucks a piece. I didn't bother checking on the double belt pulleys. Will post pics if things work out...I'm running a single 13x1170 belt with the alternator swung upwards. I had to file down the ribs on the timing cover to allow clearance for the belt.
Steve
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Hey she sounds good! Was there any exhaust hooked up? Turbo sounded great. :)
Eager for road test results. :)
That intake is evil looking!
Brendan
84 Scirocco 8v
00 Camaro L36 M49
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wowsers,
that sounds awesome Jake.
I'll be watching this project.
Thanks for posting all the details.
Ian
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Hey Jake, how did you find that info out? I found ETKA but can't find any part info there and a search of their site for the part # you gave me turned up nothing. The part also isn't listed on World Impex - did you just call them up?
Steve,
Are you running the 90amp alternator in the AC mounting style without the AC compressor? I can't picture that working... wouldn't the belt run through the timing belt? Or do you have it mounted down in the AC spot somehow?
Thanks,
Ray
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Nevermind. I found the edonkey link on the russian site, but the file was quite old. An edonkey search for "etos" turned up newer versions...
ed2k://|file|TLF-SOFT-02.20.05.Etos.v52.902.Multilanguage.ISO-TBE.bin|764799840|df6f2c4abb4ec0741f3b3a0ef9cdf935|
ed2k://|file|TLF-SOFT-02.20.05.Etos.v52.902.Multilanguage.ISO-TBE.cue|118|c9ab9a838ce6422eb2d3b03e48a7d641|
ed2k://|file|TLF-SOFT-02.20.05.Etos.v52.902.Multilanguage.ISO-TBE.nfo|10403|11b1eb0ef7858d73c483db1ffa528fc9|
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Illustration 903-40, Jetta Mexico
For alternator version 7 or 10, 10 being 068 903 033 E, 90 amp Bosch for "ME" engine code.
I didnt spend a year in VW parts doing nothing. ;)
Brendan
84 Scirocco 8v
00 Camaro l36 M49
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Brendan & Ian - Thanks! No exhaust is hooked up yet... that's why the turbine whine is so loud. Did you notice the cardboard behind the engine? That's my makeshift exhaust system. :wink:
rackley: ETKA is the VW parts microfiche; what they use at VW dealerships to look up part numbers. That 035 903 119 should be a valid VW part number. Try this link for impex lookup: http://www.worldimpex.com/search_by_partno.html?searchmode=partno&partno=035+903+119&x=31&y=7
Also, to keep this thread from getting out of hand, do you mind starting another thread to discuss steve's alt-belt/pulley modification? Thanks.
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Congradulations on getting it going.
A couple questions.
I was thinking this VNT setup came off a TDI. It bolts right up to the head but are the exhaust ports shaped the same? The intakes on the TDIs are "D" shaped (right?) but the exhaust ports are shaped the same as the 1.6 diesel?
Also what are you going to use to support the turbo outlet pipe The stock 1.6 TD uses a metal bracket that bolts to the exhaust manifold and to the turbo outlet pipe, just before the toilet bowl. This exhaust manifold won't bolt up this way.
The old 1.6 diesel had a couple brackets that attached the block and trany to the downpipe, just before it went to the accordian shaped expansion joint. It was used on the dual down downpipe setup, pre-'81 I think. A set of these brackets might work well for you.
I don't think you should leave all the stress to the turbo outlet pipe bolts, even with a toilet bowl or flex section.
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Yes indeed, the VNT turbo is off a TDI - a 2001 Golf.
The TDI exhaust ports may be a little bit larger than the original 1.6l ports, but they are the same oval shape as in any 8v VW exhaust port. And air flowing from a smaller port to a larger port should not impede flow much. I did not perform any blueprinting or port matching of the head to the TDI exhaust ports, but I did verify that the exhaust manifold gaskets I had did have large enough holes and fit properly on both sides.
Regarding the downpipe bracing... true that the 1.6lTDs with the cast iron downpipes had the bracing from the factory. But, I don't think there is any downpipe bracing in the TDI downpipe. If that is the case, I will probably not bother making any, but will just put in a good swivel or flex joint as near as is practical to the turbine outlet. Did the 1.9lTD have any downpipe bracing? I don't think it did. Must be either the switch to the "accordian style" flex joint or to the lightweight tubular downpipe construction that allowed VW to do away with the downpipe bracing.
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I don't think there is any downpipe bracing in the TDI downpipe.
Correct!
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Nice work, Jake! Sounds killer. What kind of hose did you end up using to connect the intake piping? Looks like some kind of urethane reinforced with steel coils.
Also...is there a filter on the intake right now? I see what appears to be a silicone reducer and a canister before that.
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Yep... I used the same air filter that I used in my GTD. It's a PRM filter. I special ordered it with a special silicone reducer that ended in a 2.5" diameter (their standard reducer only goes down to 3".) I custom fabricated out of 16-gauge 6061 aluminum tubing (with way more labor time that I'd care to admit... including one botched piece I chock up to learning to weld thin-wall aluminum... :? ) an aluminum transition that further reduces the 2.5" diameter to 1.75" diameter. From there I couple to the TDI compressor inlet using 1.75" diameter Aeroduct CEET (neoprene rubber, smooth internal wall, 2-ply ducting). I had previously sanded down the TDI turbo compressor inlet by about 1/32-1/16" reduction in diameter, to get the Aeroduct to slip over it. The Aeroduct is not very conforming to changes is diameter due to the way it's constructed with internal metal wire reinforcement, but does a great job bending how you want it and also absorbing engine vibrations. I also used 1.5" Aeroduct to mate the compressor outlet to the 1.6lTD intake manifold, in conjunction with a cheap nonreinforced drain-waste-vent rubber 1.5" to 1.75" adapter that I got at Lowe's Home Improvement! (I didn't care to custom fabricate another long-tapered aluminum piece.) :lol:
The aeroduct is tied together, as are some other pieces mounted here and there (air filter canister, fuel lines, turbo oil supply line) using various sizes of Adel-style clamps sourced from a local homebuilt aircraft parts supplier. As you can imagine, lots of custom work here!
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I started welding to the downpipe flange yesterday. Cutting several "pie" shaped pieces out of the 2.5" stainless mandrel-bent turbing and welding those together, I was able to make the bend radius as tight as it needed to be.
And boy is welding stainless so much easier than aluminum! :D (Plus, oh how effortlessly a powered radial arm saw with a metal cutoff wheel slices through stainless tubing... compared to a hacksaw!)
I managed to make the downpipe clear the shift linkage, but it's tight - less than one finger's thickness of clearance. In pursuit of some more clearnace, I am going to file the corner of the relay arm off. It's not a functional part of the metal arm in any way.
Finding a spot for the flex joint that is very close to the turbine outlet may be a challenge. As the tubing comes out of the turbine outlet, I had to make it bend pretty sharply downwards (only a little bit aft) to make clearance for the shift linkage. Once it was clear of the shift linkage, it needs to take a path more aftwards to steer clear of the inner CV joint and give the CV boot some breathing room. But then, (I haven't gotten this far yet with fabricating the piece yet,) it may be pointing aft too much to be able to clear the steering rack, and might need another downwards bend before it bends completely aftward, heading toward the under car shift boot. I am not sure where I'll have room to put the flex joint. The flex joint I've got is a ball and socket type construction, with two spring-loaded bolts on either side applying tension. The spring-loaded bolts have flanges that kind of stick out on either side. One of those braided flex stainless couplings would probably allow more clearance right around the tubing due to the lack of spring-loaded bolts, although it would also need be mounted on a longer straight section than the shorter ball-and-socket type joint.
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Just signed on this board - great thread. Haven't had a chance to read it in depth and sounds like you have your intake manifold setup already, but thought I would include what I found back when I was in college working at a VW Porsche shop, using a flow bench to fill the slow hours.
The NA diesel intake runners are longer, and more restrictive than the usual gas ones.
For A1 f.i. gas intakes, the earlier the better. A 77 Rabbit intake flowed considerably better than an almost identical looking 83 Rabbit GTI intake. The Fox intake manifold (which has the throttle body on the same side) flowed slightly better than the 77 Rabbit one, and only slightly less than the A2 style intake. Yes, those runners are bigger and it does flow better. I never flowed a G60 intake, but I imagine it is likely as good a one with a drivers side throttle body opening as VW made.
Consider making a brace for your downpipe. Several local friends with gas VW Turbos have cracked their downpipes, and being custom, have to go through pains to repair them. Can't hurt and may improve reliability. And yes, they had nice flex-couplings.
Nice write up and pics - keep them coming and good luck!
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In the middle of fabricating the downpipe:
(http://www.imagestation.com/picture/sraid169/p067d2819f7cbc1a496efadee8255a46b/f410e40e.jpg)
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Jake,
looks very nice. With the hours you currently have in this thing, be very glad you're not paying a shop to build it for you...
And don't forget to install a support bracket for the bottom of the turbo.
-Dave
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Thanks Dave - I've been meaning to ask where does the flange at the bottom of the turbo bolt to on the TDI motor? I can't find an obvious place that looks like it should bolt to on the 1.6D motor, and I also can't find anything that looks like a turbo support bracket in ETKA for a 2001 TDI Golf.
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There are numerous bosses on the back of the TDI engine block.
This is the best picture I have, but it still doesn't show the boss that the support bracket bolts to:
(http://gli.trouvist.com/k/DSC02951.JPG)
The support bracket is simply just a short angle bracket, comes off the turbo, bolts to the block.
-Dave
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Try an 038 145 535 B
It doesnt look like much in the picture (145-55) but the pic of the turbo is pretty much generic so who knows what it actually looks like. There's also the one for the 1.8t, 06A 145 536 B but I doubt that would fit. All else fails, get some angle iron and weld er up. ;)
Brendan
84 Scirocco 8v
00 Camaro L36 M49
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Thanks for the turbo support bracket info and part numbers, guys. Looks like it is not that expensive of a part; impex lists either one under $20. I will have to check out what it looks like on a TDI.
The downpipe is now finished. I managed to position the flex joint not too far away from the turbine outlet:
(http://www.imagestation.com/picture/sraid169/pf9f17ca960305670e5fee44f86e14acb/f40d9aad.jpg)
(http://www.imagestation.com/picture/sraid169/p64ebd09ccdd21d755f128a6f430c848d/f40d99ec.jpg)
Installed:
(http://www.imagestation.com/picture/sraid169/p62c96d79d398033650543d7bce0ea6ca/f40da2ee.jpg)
(http://www.imagestation.com/picture/sraid169/pbfb4bb6cb75cc667da701fcf9158cac1/f40da28c.jpg)
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Nice job, I can't wait to see how the car performs!
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That's some top-notch fabrication work, Jake!! WOW! :shock:
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Jake,
what diameter pipe did you use for the downpipe?
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Thanks guys! :)
Update: I finished the installation of the under-car shift boot, which was a challenge with the EMPI Rabbit shifter. Will post the details in the "EMPI Rabbit Shifter Review" thread: http://www.vwdiesel.net/phpBB/viewtopic.php?t=1146
I wanted the boot installed before I did the exhaust in that area, so I could make sure I routed the tubing in a way that didn't interfere with the boot.
Staley: I used a mixture of stainless 304 and 409 grade 2.5" OD tubing for my exhaust fabrication work. The 2.5" tubing diameter will be maintained until after the under-car shift boot, where I will couple to the old 2.25" exhaust system. There is an old resonator before the over-the-axle pipe; I could either adapt to that or cut it away and adapt directly to the 2.25" over-the-axle tubing. I have very little doubt that it will be quiet either way with the 2.25" dynomax super turbo muffler.
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Here is what I did for the turbo support flange. I cut some electrical conduit, and pinched and drilled holes in the ends. I mounted it to a boss on the block that was fairly close to the turbo support, where I installed an 8mm stud and shouldered locking nut. To fasten to the turbo support flange, I managed to come up with a 10mm bolt and nut / lockwasher that fit pefectly.
(http://www.imagestation.com/picture/sraid169/pa4f550151ed977e0aa90ddb7225299cf/f402eef4.jpg)
I am almost done with the exhaust. I cut away the old resonator, which was quite heavy and seemed to be pretty plugged with carbon (not sure if it was doing much!) I just have one weld connection left to complete the exhaust system. I had to take off the front antiswaybar to remove/install the exhaust piece I am working on. It spans from the flex joint all the way past the under-car shift boot. The new gauges are also now all wired in too (gauge lights and everything.) Should be able to monitor EGTs now.
The Mann Provent arrived. Looks like a high quality unit, but it is quite large! :shock: It's gravitating towards being installed next to the windshield washer fluid reservoir, behind the battery. There is enough room for it there. But I'll probably delay installing it until after I drive the car!
I want to take this VNT action out onto the road already! :twisted:
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I finished the exhaust and test drove the 1.6 VNT Rabbit today! I'll post details of the latest exhaust work I did later, so skipping to the test results: It turns out that the vane controls are not working right on this first iteration of the manual VNT controller. What happens is that when RPMs and/or load get high, the boost pressure skyrockets, easily pegging my 15psi boost gauge (I tried to keep it from doing that.) So I suspect the vanes are not opening (or if they are, they are not opening enough!)
But it worked fine on the test bench... so, what I suspect is that the exhaust airflow through the vanes is applying a rotational force on the vanes and preventing them from opening like they did on my test bench (completely open by 15psi: http://www.vwdiesel.net/phpBB/viewtopic.php?t=1306&start=28) Pretty interesting results.
Luckily there is a lot of room behind the turbocharger, and I modified the can so it can be opened and closed again, so this means I might be able to try different iterations of the VNT controller without a whole lot of fuss. Maybe I can even unbolt the VNT can from the turbo without removing it from the engine! :D
Some good things from the first road test: the exhaust system seems aligned perfectly, no rattling at all. The new motor mounts are nice and tight and engine idles quite smoothly with minimal vibrations. All the coolant hoses and the coolant level held, so the new head gasket seems to be working. No oil leaks anywhere. Basically, everything besides the VNT controls worked great!
The engine even SOUNDED great with the VNT. It was pretty unique and interesting sound. Distinctly different from the low-pitched whine of a 1.6lTD. You can hear a distinct sound out the muffler that sounds sort of like rushing air combined with a faint high-pitched whistle, but overall it's nice and quiet exhaust noise even without the resonator.
This turbo just spools up SO quick. It's totally crazy. If I can harness the VNT by figuring out a way to control it, this is going to really broaden the torque band down into the low RPMs. I verified that it does put out boost pressure at idle. I didn't even trust the gauge was working as this seems so amazing to me, so watched the gauge as I turned off the engine. It dropped downwards, all the way to zero, right after being shut off! When fully warmed up, it is probably putting out nearly 1/3 of a psi AT IDLE. Amazing stuff.
The engine also seems like it might start and stop more abruptly, why exactly I don't know but seems different somehow with the VNT. Either it's because maybe more pre-turbine backpressure... or maybe there is more compression during starting with the VNT assistance!
During the test drive I tried a short freeway section (didn't work very well with overactive VNT... had to keep speeds really slow to keep from overboosting) and anyway the cheap boost tube adapter I clamped on there blew off. Nothing too traumatic - I've had this happen on my GTD Autocrosser 1.6lTD before I got the boost tubes beaded behind the hose clamps. I knew what it was, and just put on the hazards and snailed very slowly to the nearest exit and parking lot. Well when I kept the enigne idling and popped the hood to replace the blown-off boost hose, I was surprised how STRONG the wind coming out of that open boost tube was! I mean I don't know how fast a 40mph wind is or whatever, but I can just say this was a really strong wind. Not like what a 1.6lTD would be blowing at idle for sure! It really seemed amazing.
Now that I've gotten a sense for how quick spooling the VNT is capable of, I wouldn't mind just hardwiring the vanes open now and driving it around like that to get a sense of what the VNT-15 is like with vanes open. IE: see if I can get it to make any boost at all like that, or not.
I am not really sure yet exactly what I'm going to try next for the vane controller. I must admit I am a bit concerned after learning that the only other non-TDI production car that came with a VNT turbo, the Dodge Shelby CSX, had also used computers to control the VNT vanes. Knowing that no other manually-controlled VNT turbo'ed cars have been produced is not confidence inspiring! :?
Edit: here is the latest picture update...
fabricated center exhaust tube:
(http://www.imagestation.com/picture/sraid170/p35c784aa5e1ff64ba4caab2990f2bb70/f3fffd1b.jpg)
installed:
(http://www.imagestation.com/picture/sraid170/p6e05b0e352fa758022b44d745d3ca071/f3fffe62.jpg)
a little detail you Rabbit folks might like - I increased clearance for the exhaust by extending the bracket that holds the fuel tank mounting strap. The strap now is held much closer to the fuel tank, allowing more clearance for the exhaust tube which passes underneath. This worked wonders for aligning the 2.25" techtonics over-the-axle exhaust pipe.
(http://www.imagestation.com/picture/sraid170/p28c09d7cae3600978ec4751d58318842/f3fff82a.jpg)
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Really interesting result Jake.. VNT spool in a blink of an eye and is capable of a 18-19psi substain w/o problem.. In the case that you can't make this thing work mechanically, i probably can make something for you.. Keep us informed! Good work!
Marc/
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what I suspect is that the exhaust airflow through the vanes is applying a rotational force on the vanes and preventing them from opening like they did on my test bench (completely open by 15psi...
Could you use a softer spring for resistance in th can to end up with fully open vanes on the bench by 6 PSI?
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Jake, you can adjust the VNT initial position by twisting the threaded VNT actuator rod. You can find out more about it by searching TDIClub with the keywords "negative VNT twist" or some variation thereof.
You want the vanes to be more open initially.
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what I suspect is that the exhaust airflow through the vanes is applying a rotational force on the vanes and preventing them from opening like they did on my test bench (completely open by 15psi...
Could you use a softer spring for resistance in th can to end up with fully open vanes on the bench by 6 PSI?
just control the original vnt actuator with a mechanical boost valve and a restrictor. the vnt will be fully closed until you hit the setpoint.
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Sounds like you just need a boost gauge with a higher reading :wink:
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All I need now is a new video in my mailbox :twisted:
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Thanks - you guys are great. So many different responses and opinions - each of them are actually good ideas too.
I did some testing today I wanted to share. All the results are not yet in, because the clutch started slipping from all the torque and well, I can't really test it at full load when the clutch is slipping like that. But anyway, I can tell you about the results before the clutch slipped.
I found I was able to easily adjust the VNT linkage as well as remove the VNT can from the turbocharger without having to remove anything else. I can get to it all just leaning over the engine and reaching behind the intake manifold; and the VNT linkage is just right there. It really couldn't be much easier to access! :D
For my first test, I wanted to see what the turbo response would be like if I just did quick and dirty adjustment to open the vanes more, without removing the VNT controller can or doing anything more involved with it. Due to limited number of threads on my VNT controller rod, I was only able to open the vanes by about 2.1mm (out of a total of 4.7mm travel), while maintaining a reasonable amount of thread engagement. That means the VNT would now rest at about 45% open instead of all the way closed. This was all I could easily get the vanes open by just doing an adjustment on the threaded adjuster. I took it for a spin in the "vanes 45% open at rest" configuration... First thing I noticed, was that the boost pressure at idle was gone. Driving around, I found that I still had to limit throttle and RPMs as the vanes were not adequately controlled, although the turbo was significantly less hyper-active than previous test with the vanes pre-set to all the way closed at rest. (By the way, by all the way closed, I mean that the vane adjuster lever is sitting on the untouched factory-set stop.) On the freeway now, I could reach a 65mph cruising speed, but just barely without the boost spiking out of control with the slightest twitch of the throttle foot. I found boost pressure at a steady 65mph cruise to be about 7 psi, but it didn't take much to get it to jump to 10, and it would jump past that very easily if I wasn't watching the gauge or thinking about the throttle. Because of this, I had to keep speeds limited to 65mph. I would also generally characterize the low engine RPM turbo boost response in this vane configuration as being close to a stock 1.6lTD, but still more responsive, with a little bit quicker boost build-up happening at lower RPM.
For the next test, I really wanted to see what it was like with the vanes all the way open. I got creative and completely unscrewed the vane control linkage, screwed in a bolt in place, hinged the works up near the turbo oil supply line and secured it by the bolt using a small hose clamp to the oil supply line in the vanes 100% open position. This was obviously just a quick and dirty jerry-rigging. Turbo response was much slower now, and it took more load and RPM to build boost now. I would say it was still close to, but now was less responsive than a factory 1.6lTD in terms of boost versus RPM response for lower engine RPMs. Also generally, there now would not be any boost pressure when the throttle was lifted or when loads were low. Cruising at even 65mph now happened at zero psi boost. But, pressure would build when the foot went down. For the first time I was able to try put some torque down without the overactive VNT threatening to overspin the turbo as a result of doing so. Trying to put down high loads was when I found the clutch in this configuration started to slip. It generally took about 5-7 psi at near full load to make the clutch slip. That limited testing to see how much higher the boost climbed, although I seem to recall it getting close to 10 psi. So anyway, I've really got to get the clutch replaced now before I can complete this test and see how much the boost builds at wide open throttle with the vanes totally open. I am a bit surprised they do not regulate boost pressure like a wastegate. I was sort of expecting there to be zero psi (or something very close to that) at all times with the vanes 100% open, but apparently this hyper-active VNT turbo just doesn't work like out old wastegated turbos in that regard. The TDI VNT is apparently built to boost! --but, even with the vanes all the way open? :? I guess the VNT control problem could have a solutuion, as long as the peak boost pressure at full loads with the vanes all the way open isn't too high! I'll have to wait to get a new clutch to try.
If the turbo overboosts even with the vanes all the way open, one band-aid solution might be to limit engine torque (reduce fueling). That kind of sucks though! Another band-aid solution would be to install a post-turbine restriction in the exhaust (which after fabricating that large free-flowing exhaust system, I would really hate to do!) A better solution would be to install an external wastegate to run in conjunction with the VNT as boost control. There is a wonderful spot to mount it too; the EGR flange! An external wastegate would be extra time, $, and stuff taking up space under the hood, however.
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I really think changing the spring is your best bet. Obviously the spring pressure is too high to allow adequate travel given the boost range you're working in.
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Jake,
The VNT will make lots of boost all the time, as you have found out. Very quiet idle and low speed operation also defined the VNT, albeit for amazing turbine and compressor sounds! About 6 years ago, I fitted a slightly larger VNT to my 2.4L 6 motor with similar results as you; I measured 1.35 psi at idle with a manometer with the vanes fully closed. 5 psi came at ~2.5K rpms, and at 3K rpms nearly 10 psi was developed, all no load! Using an electronic peak/hold boost controller I designed, I was able to largely control the amount of boost to approximately 21 psi. In addition, I had to adjust the tension rod quite a bit, and change the displacement angle of the actuator with respect to the vane control lever. City driving was amazing; instant "throttle" response, and massive torque. The car simply squirted through traffic at nearly any engine speed.
The problem is that you do not always want maximum boost and nearly always closed vanes. At steady state highway cruise conditions, the boost would hover around 11 psi, instantly shooting to 20+ with the slightest deviation in the fuelling lever. AIT was unnecessarily high (higher than with the previous turbo) and EGT was up as well. All bad for good specific fuel consumption. Greater angles of the vane lever yielded lower AIT and EGT, but response suffered.
Several iterations later, I designed a circuit which included a differentiator that measured the rate of change in the throttle angle, coupled with feedback from manifold pressure, and AIT. For low speed operation in traffic for instance, in general, the vanes were closed most of the time. However, if traffic opened up the circuit would go into a cruise mode, where the vanes would nearly fully open for low pumping losses, low AIT, and lower EGT. Mileage was way up as well, it was discovered. If, for example, I needed to pass, etc. on the highway, the circuit would determine the rate of change in throttle, and instantly go into high response mode, closing the vanes, and furthermore, controlling the boost at higher engine revs. Based on qualitative and quantitative analysis, this appeared to be the best way to getting the most out of the VNT device.
Hope this helps 8)
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Several iterations later, I designed a circuit which included a differentiator that measured the rate of change in the throttle angle, coupled with feedback from manifold pressure, and AIT.
WOW! Want to patent that device? ;) That is incredible. Where did you pick up the components for it, from automotive sources or elsewhere?
This is proof why I spend more time on this message board than any other. :)
Brendan
84 Scirocco 8v
00 Camaro L36 M49
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Several iterations later, I designed a circuit which included a differentiator that measured the rate of change in the throttle angle, coupled with feedback from manifold pressure, and AIT.
That sounds great, and wow, what a first post!
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[Hijack]2383 GTD, Welcome back long time no post!
All of your posts on the old board mysterioulsy disapeared. Good to have you back. You will have to give a run down of your latest mod state of the volvo. Albeit in a differnt thread :wink: [/hijack]
Ahh clutch slip from to much torque, words I love to hear. What are you planing on using for a replacment clutch?
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WHAT is wrong with this board..
who would think that anyone would really be addicted to a
freakin diesel board! LOL
I find myself checking for new posts like 20 times a day
and eagerly wait for Jakes new posts on his car
at least I know that I am not alone here :)
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WHAT is wrong with this board..
who would think that anyone would really be addicted to a
freakin diesel board! LOL
I find myself checking for new posts like 20 times a day
and eagerly wait for Jakes new posts on his car
at least I know that I am not alone here :)
Amen Brother.
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WHAT is wrong with this board..
who would think that anyone would really be addicted to a
freakin diesel board! LOL
I find myself checking for new posts like 20 times a day
and eagerly wait for Jakes new posts on his car
at least I know that I am not alone here :)
Don't worry, you'r not alone.. :lol:
Marc/
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2383 - good to see you around! Wow, didn't realize you did an IDI VNT so long ago! :) Wow, 22 psi, that is some pretty healthy boost. Did you leave the vanes as being vacuum controlled when you adapted the electronic controls to it? Also, do you recall any testing of how the fuel economy actually changed as a result of running the vanes more open while cruising on the freeway vs "closed vane cruising / hyperactive boost" mode? I'm wondering how big of a difference it might make.
Guys: I made some progress today on the VNT control front. Since flipping over the diaphgram inside the VNT can and putting the spring on the other side, the spring has been put under a much higher pre-load than it had originally with the vacuum control orientation. This is because the outer half of the VNT control can had a recess that interfered with movement of the metal structure of the diaphgram after it has been flipped over. You can see the recess well in this picture - it is the area around where the hose nipple is installed:
(http://www.imagestation.com/picture/sraid170/p7c4bd7d6d29d3885b74458063a4398bb/f3f922ba.jpg)
So to make the can more adjustable so it can react to smaller boost pressure signals, I flattened out the recess in the end of the outer can half to reduce the spring pre-load. I did this by pressing the recess in the outer can half more flat with a vice:
(http://www.imagestation.com/picture/sraid170/p9074885eb8ace3f2a31583ab20ef7adb/f3f92602.jpg)
result:
(http://www.imagestation.com/picture/sraid170/p9bbcc4efc59ccf92843bbb530c111bd5/f3f92670.jpg)
The VNT controller now has much less spring pre-load and also has a longer range of travel and so is much more adjustable. It can start moving now with less than 1 psi of pressure in the can. Before when the spring had a higher pre-load, it took 6-7 psi pressure in the can before the rod would start moving.
Here are the VNT can parts I now have available to play with, including the 3 different lengths of shafts (at left, the ruler plus the stock riveted-on shaft are shown for reference):
(http://www.imagestation.com/picture/sraid170/p5bc34b2bd285d51c38fde282adf8da9b/f3f925c1.jpg)
I assembled it with the longest shaft (previously I used the medium length one.) I can't wait to get the car back up and running with it's new clutch because I'll be ready for some more VNT testing and experimenting! :twisted:
Here is what the latest iteration of the VNT can now looks like:
(http://www.imagestation.com/picture/sraid170/pb8b06ae4d79cbc3b39586b76ead66b67/f3f9263d.jpg)
PS - I found with advise from Garrett tech support on how to adapt their VNT-25 (left over from Dodge Shelby CSX production) to use in other aftermarket/motorsports applications. Of interest is that they propose that manual boost pressure on the VNT can can be a viable means of controlling the VNT. They also mention a wastegate can be used in conjunction to the vanes to further regulate boost pressure. http://www.thedodgegarage.com/turbo_vnt.html
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DVST8R - I am in the process of installing a new 210mm clutch and matching 8v pressure plate with a brand new flywheel I just today got back from having lightened:
(http://www.imagestation.com/picture/sraid170/p492880ec342c2a5366271538584d4674/f3f9251e.jpg)
Luckily this flywheel didn't have any balancing marks on it's outer weight ring, so I skipped having it balanced after the weight ring was peeled off. Since the material was removed evenly from the outer weight ring only, which ran true and was turned on a lathe by the factory to start with, it should remain as well balanced as it was by the factory if the metal is uniform in density. Jerry, my machinist who I trust and who has also lightened a lot of VW flywheels, thought it would work. I sure hope he is right! Here is a shot of the action in the machine shop earlier today:
(http://www.imagestation.com/picture/sraid170/p5238e98da52d70e7487a569e1c5627e6/f3f92ad9.jpg)
I still have to connect the motor mounts and drive shafts to get the car driving again, but the transmission is back mated to the motor with the new clutch and flywheel goodies bolted up. Looks like a bad clutch push rod bushing and seal are what took out the old clutch... it seemed to have had good usable meat still left on the disc, but it was slipping apparently because of oil contamination. In addition to changing the push rod bushing and seal, I also changed the engine rear main seal and tranny mainshaft seal while I was in there. And I took the opportunity while the transmission was out to pressure wash it at the coin-op car wash. It is so nice to have the grease-cake eradicated. :)
While I had the transmission out and the passenger driveshaft was hanging down and out of the way, I header wrapped the downpipe where it gets close to the inner CV boot. I was worried about the heat from the downpipe that passes close to that CV boot from accelerating the aging of the rubber. Installed on the TDI, I noticed that there was a metal heat shield protecting the passenger inner CV boot from the downpipe heat, but I didn't have enough clearance to be able to use a metal heat shield. Hopefully this header wrap will do the trick of allowing the rubber CV boot to last and also keeping the CV joint cool!
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Thanks guys, it is good to be back.
Brendan, thanks for the kind words. Basically, the design was a solution to the problem of properly controlling the VNT. The components were from scientific companies, that I was able to source when I worked at NIST. I had to do all the design work, as none of my professors knew what the hell I was talking about... they were too into research.
Jake, the controls were pneumatic, but later servo controlled :twisted:
You will also find, perhaps even now, that even with the vanes fully open and enough fuel, they will no longer control peak boost. Later, after more fuelling increases, I had to use an external WG coupled with the vane controls. The WG is normally obligatory with gas engines that use the VNT.
It really depends on the relationship between the turbo and the VE of your motor, but with the vanes tightly closed, fuel economy did suffer. When you get fully up and running, try some tests with the vanes, and see how much it effects mileage, and report back to us.
To all, look for more posts about my car, and some pretty major developments I've made with it with regard to the power output, and injection pump modifications. I also have some big plans coming up as well.
Some already have known this for awhile, but it turns out that someone hacked into my account on the old board. I created the username on this board, but wanted hang back to see if I was able to find out who did it. Very uncool, as I had a lot of good info in the posts.
Several iterations later, I designed a circuit which included a differentiator that measured the rate of change in the throttle angle, coupled with feedback from manifold pressure, and AIT.
WOW! Want to patent that device? ;) That is incredible. Where did you pick up the components for it, from automotive sources or elsewhere?
This is proof why I spend more time on this message board than any other. :)
Brendan
84 Scirocco 8v
00 Camaro L36 M49
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>> Installed on the TDI, I noticed that there was a metal heat shield protecting the passenger inner CV boot from the downpipe heat, but I didn't have enough clearance to be able to use a metal heat shield.
Jake...
Not sure what the TDI heat shield looks like in that area, but on my Cabriolet and I believe on one of my rabbits, there was a stock heat shield around the passenger inner CV.
I believe it was metal on the rabbit and some sort of plastic/fiber material on the cabby. It bolted to the back of the block with some huge bolts (10mm?) and seemed to be pretty effective.
Any chance you can modify a stock A1 part to fit that space? I'd imagine space is tight. I'd be interested in the results...
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I got the car running again today, and also now I am driving it around for a little while. :) Something in the clutch/bellhousing area made a weird noise right after I started it to begin with, but the noise went away after a little bit of driving - weird. Anyway, the new clutch is holding much better than the old one ever did, and it feels great. The car feels much peppier going from a stop now with the lightened flywheel, it is nice. Basically, this car is already getting really fun to drive! :)
The way the VNT drives set fixed to 100% open is like driving a turbocharged car without a wastegate. It seems like the turbo is matched reasonably well to the engine, but it makes it's peak boost only at high RPMs with high loads. In all other conditions it doesn't put out peak boost, and it does not boost much at low RPMs. It is sort of a "peaky" setup with the torque climbing as RPMs climb. It is fun to drive and rev the thing up and the car takes off like a rocket, but is going to be even better when I get the VNT controls set to also make some boost at lower RPMs. Another interesting thing is that I can see in the boost gauge when the governor pulls back the fueling, it causes the boost to reverse direction, and start dropping, instead of continuing to climb.
Veeman - that is interesting the cabriolets came with a different style of inner CV heat shield. I'm pretty sure the TDI inner CV heat shield was sheetmetal construction. But anyway, there really is just not enough room for any shield besides a single ply of header wrap insulation, or I would be worried about it rubbing on the CV boot. Today after driving the car quite hard and pulling over and popping the hood, I felt the header wrapped part of the downpipe. I was quite surprised that it did not burn me! In fact, I was able to touch it (probably not hold my hand there forever, but still, seemed quite cool.) It seems to do a good job insulating and hopefully should do the trick of keep the heat away from the inner CV boot. The stainless steel of the downpipe should also help limit the transfer of heat, although the tubing is not all that thick. I am glad I added the header wrap.
2383 - got any pictures of your servo motor VNT control setup? That sounds really cool! :P A wastegate seems like a really nice thing to have with a VNT turbo because in the event of a VNT control failure, the wastegate would serve as a fail-safe, preventing turbo over-spinning. Testing of the 100% open vane position is still ongoing, but earlier today I hit 15psi at the peak of a really strong second gear pull. 1st gear seemed over before it begun, and did not muster up anywhere near that much boost. I still need to test what the boost does at full load and high RPMs in 3rd and 4th gears with the vanes open.
Edit: I started a "want to buy" thread for an external wastegate. If you might have any pointers on what I should be looking for this application, please check the thread out:
http://www.vwdiesel.net/phpBB/viewtopic.php?p=11213
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I did some testing today... I verified that I can still reach the upper end of the 15 psi boost gauge at high load/high RPM even with the vanes all the way open! This is with stock, unmodified 1.6lTD fuel injection pump and settings. I took some videos during the testing that I will forward to blades for hosting! :)
By the way, today was a really lousy day to test on the freeways with memorial day traffic; I found it hard to get clean stretches of highway. Seattle traffic totally sucks but memorial day weekend traffic is the worst of the whole year I think! :? But I did enough testing to come to the conclusion that I am going to get an external wastegate.
After testing with the vanes open and with the stock fueling levels, I dialed back the main load adjusting fueling screw by 1/3 of a turn and did some more testing. With the car noticeably down on power with the fueling limited like that, the turbo still put out lots of boost, although this time at least it peaked in the readable range of my boost gauge, peaking at 12.5-13 psi. Although I feel this is a reasonable peak boost pressure to run on a daily driver, which must be very reliable, I am not too pleased with the performance after dialing back the fuel.
What I am finding about this VNT turbo is that it simply pumps more air than the IDI diesel motor needs, even with the vanes all the way open. So to properly install it on an IDI diesel motor with modest boost pressure, it needs something to help slow it down besides VNT control modification: either a wastegate, or maybe turbine blades clipped, or vanes modified to open more than they do standard, etc.
I really need to roll a bead into my boost tube fittings, as I am finding that they keep blowing off. I found a small amount of oil in the boost tube that must have come out through the compressor bearings/seals. I am not used to seeing any real amount of oil out of good running 1.6lTD garrett turbos, so I hope this oil doesn't mean the VNT turbo has already started to go south! :oops:
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That's a bit scary- I've read over and over on TDIclub about people popping VNT-15's all the time, hope it didnt happen to yours!! Although I think the majority of the failures are turbine shafts snapping, from what I remember they are hollow and people with aggressive tuning chips can accellerate the turbine faster than the little shaft can hold. I dont remember a lot of people complaning about seals leaking though. Perhaps the high boost is causing some blow-by into the intake?
To change the subject, based on your driving impressions so far, how do you think the VNT would work with a properly modified injection pump, AKA the "Giles" way? Do you think boost responce would match the pump output? Would there be enough boost? Probably hard to judge when you are still ironing out the boost, but how about some preliminary observations? ;)
Looking forward to those vids!
Brendan
84 Scirocco 8v
00 Camaro L36 M49
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based on your driving impressions so far, how do you think the VNT would work with a properly modified injection pump, AKA the "Giles" way? Do you think boost responce would match the pump output? Would there be enough boost? Probably hard to judge when you are still ironing out the boost, but how about some preliminary observations? ;)
I think a VNT would work very well with a modded pump that increased fueling at upper RPMs, provided you did something to slow down the compressor. With pump mods, the problem of uncontrolled boost at high RPMs and loads would be even worse. You would need something like an external wastegate, "clipped" turbine wheels, etc even more badly than I need it with the stock pump settings! I would envision a very wide powerband with that setup that would be enormously driveable. Compared to stock 1.6lTD, the powerband would be broadened both downward in the engine RPMs as well as upward.
Edit: by the way, since the blow-by is currently routed direct to atmosphere, I have ruled it out as a source of the boost tube oiling. It's gotta be coming from the compressor.
Also, just sent the testing video I recorded earlier today, VNT_Testing.wmv (1.2MB), off to Blades for hosting. Thanks Blades! :D
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This video
Right-click; Save AS;
http://www.boucanne.com/per_images/video/VNT_Testing.wmv
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Clipping the turbine will kill the efficiency. Don't do it. Use a wastegate if you must. Or just enjoy the boost ;)
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couldn't you simply use some sort of BOV that opens at 10-15 psi ? (in conjunction with something to control the vanes...)
I envy you!!! I thought changing from the K24 to a K14 was awesome, until I saw your VNT!!!
btw, how much do these turbo's cost? are they K03's? (would be nice to get one)
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A BOV is not ideal for constant use. That's because it just relieves manifold pressure by bleeding charge to atmosphere. This increases pumping losses because the turbine still works to compress to complete charge air mass, including that which is bled away.
Wastegate is the best bet if you must.
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Yup. You could use a pop off valve to protect the turbo from reaching too many revs, and they can be had for less than a proper wastegate. But, venting the charge, as written below by TDIMeister, is very serious.
I lost power on one of my cars due to a slightly leaking bov. The adjuster was then set to increase the spring tension, and the power went up by 100 whp whilst on the dyno :shock: . Yes, 100 whp. Any charge leaks, even small, result in large pumping losses.
A BOV is not ideal for constant use. That's because it just relieves manifold pressure by bleeding charge to atmosphere. This increases pumping losses because the turbine still works to compress to complete charge air mass, including that which is bled away.
Wastegate is the best bet if you must.
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I've got the factory 1.6lTD blow off valve/intake manifold on the engine, which is not a bad thing to have as a little protection for the engine against VNT malfunction or overboost, etc. I used it once on my first test drive when I had the vanes all the way closed, and I pulled out into a street to discover a speeding car approaching from behind quickly closing the gap. I had to put the throttle down farther than I did at other times during that test session, and the boost went off the gauge range and the blow off valve opened. When the factory 1.6lTD BOV opens, it drops boost pressure down all the way to around 5-7 psi or so, and it takes a long time to reset so the boost starts building again. It's not really designed for active boost control, just as a safety engine protection vent.
I agree with TDImeister that the wastegate is the way the go, as it will relieve pre-turbine backpressure and lower the rpms of the turbo. I am now looking to buy a 38mm wastegate, shooting to install it early next week.
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I had some time recently to play with the VNT settings while I am now waiting for the wastegate to arrive (http://www.vwdiesel.net/phpBB/viewtopic.php?t=1563). I am keeping the fueling set at 1/3 turn less than stock 1.6lTD to reduce risk of the boost creeping out of control or doing bad things if the VNT seizes or something before the wastegate gets in.
Previously, when I had the vanes hard-set to all the way open with the fueling reduced, the peak boost was limited to about 12psi (measured at the top of 3rd gear), but the car was not all that powerful off boost, not much torque when the RPMs were low before the boost kicked in. Well now, I installed my nifty new VNT controller with quicker-reacting spring. I initially installed it so it rested at about 50% open, which was a noticeable improvement in making the turbo react better at lower RPMs, and so then I went on and adjusted it so it just sits at 0% open with almost zero spring preload. So basically any pressure applied, even a fraction of one psi, starts the vanes opening, but they rest at full closed when there is absolutely zero pressure. It ended up putting out just a wee bit of boost at idle, although did not seem to be the full 1/3 of a psi strength it had before when I had the vanes more tightly held closed. But now it is obvious that the VNT vanes are definitely moving and the controller is trying to regulate the boost pressure, and it seems to be functioning smoothly and reliably.
With the current VNT controller setting, the boost is quicker to jump to 3-4 or so psi with some throttle application at relatively low RPMs, and the boost climbs more as more throttle is applied and as RPMs rise, quickly up to about 7 psi, then slowly creeping with rising RPMs past then (it seems the vanes must be completely open by about that pressure.) In theory I should be able to see 12psi at the top of third gear at wide open throttle, but due to bad weather and traffic was only able to manage testing the top of 2nd gear, where I saw 10 psi. At freeway cruising steady at 65, it sees a comfortable and controlled 4-5 psi. It is managing to turn out decent powerband, torque, and driveability even with the pump dialed back by 1/3 of a turn! That's because the VNT is giving such a broad boosted powerband and the pump is kicking into "boost pressure / fuel enrichment" mode so often at such a broad RPM range, I reckon.
Oh yeah I also took care of my blown boost tubes problem by flaring the end of the problem hose nipple.
I am noticing when I pull away from stops after sitting idling for a while, there is a small cloud of what looks like oilsmoke left behind. Not good - I wonder if it's valve stems/seals or if it's from the turbo. I will continue to monitor. The good news is that it is clean as can be, never smokes dark diesel smoke at all, whereas before with this was naturally aspirated with the loose timing belt, it had a real smoking problem and we probably would not have even noticed any oil smoke if it was present! I don't know what to do there, probably will just wait it out and drive it more and see if the problem is stabilized or if it worsens, and monitor oil consumption.
I can't wait to get the wastegate on there and pump the fueling back up to stock 1.6lTD levels... I really have a feeling that that this thing is going to rock! :twisted:
PS - one more test for me to try this week before the wastegate arrives... I'd like to try increasing the VNT pre-load by 2-3psi so it doesn't lift off it's full closed position until a little bit longer. Ideally this won't raise the peak boost pressure but will make it reach there quicker and open up even more power and torque at the low to mid RPMs, making the car even more driveable. :P
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The powerband of the engine in spite of the 1/3-turn reduced fuelling is partially on account of the fact that the VNT-15 is quite a bit more efficient than anything installed in the factory 1.6-era.
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hey just thought I'd add this site I found online. Near the bottom it has an animation of how the vanes work!
http://www.technologie-entwicklung.de/Gasturbines/VNT15-Turbo/body_vnt15-turbo.html
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Nice find jtanguay! That certainly clears up any confusion in relation to how Jake's VNT is being controlled. :P
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I did some testing today... I verified that I can still reach the upper end of the 15 psi boost gauge at high load/high RPM even with the vanes all the way open! This is with stock, unmodified 1.6lTD fuel injection pump and settings. :)
:shock: Nice!
So, Jake, given the 15psi full load boost (or close to that) with stock fueling and fully open vanes, it must be assumed that if one were to increase fueling to match that boost level, the boost would stabilize at an even higher level yet again. Any idea what full load boost level one might stabilize at with fueling to match in a 1.6 IDI setup? I'm just curious if the wastegate would be a truly necessary piece of hardware for a 20psi max. setting. Then again, me thinks there might be an issue with touchy throttle response at highway speeds all the same without WG control as well, after reading some of what 2383 GTD posted about his project. :roll:
Your really doing an incredible job of keeping us all in loop about this project Jake! I for one am grateful and am learning new things to be sure. Thanks.
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I wouldn't expect the wastegate to eliminate the "touchy boost/throttle" problem, since it only operates at peak boost levels (IE: you would want to tune the wastegate so that it only opens when the vanes are completely open). I have noticed with the VNT controller set to begin closing vanes at low boost, so it operates over a broad pressure range, IE: it gets rid of that "over-reactive" boost feel on the highway. But having the VNT control operate over a broad pressure range also means that you will only see a portion of peak boost low in the RPM range, so it is a tradeoff. I plan on doing some experimentation through after the wastegate gets installed and I have the fueling turned back up, to see if I might happen upon a "happy medium" kind of setting.
If you were to install a VNT without wastegate and were to keep increasing fueling, I have a feeling that the boost pressure would keep rising and keep pushing more air into the engine, and always keeping one step ahead of the fueling. It just seems to be the nature of this turbo... I think it just has too low of a turbine A/R ratio for efficient non-wastegated operation. Ideally, you can inject enough fuel to burn the air, at least up until the point where it is on the verge of starting to smoke.
If you were willing to live with modest fueling levels or really high boost levels, you could do it without a wastegate. I can't experiment in that area given I have no intercooler installed on this motor, no piston cooling oil jets, and also need to keep risk levels of damaging the motor from high cylinder pressures and temperatures low, since this is my dad's daily driver.
I did another VNT adjustment, which positively enhanced the torque band: I pre-loaded the VNT adjustment by 1.5 turns so it takes a little boost pressure before the VNT controller starts to close the vanes. Seems to build more boost pressure a little more quickly now, but it still seems well-regulated at around 7-8 psi (after which point creep is gradual with increasing RPMs at wide open throttle to a max of 10psi.) Why it's not creeping up to 12psi like it did before when I had the vanes wired closed, I am a little curious about. I wonder if the vanes may have opened up a little bit more, or if it's somehow a fuel density thing (hot versus cold fuel), or some environmental factor making the turbo have to work harder to develop the same amount of boost pressure. (Has been wet here lately... but was dry before.) It is a little bit curious though. That is tested with WOT runs in both 2nd and 3rd gear with RPMs increasing all the way until the point where the intermediate spring starts working to decrease the fueling.
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hmmmm now where the heck can I get me a VNT for my 1.6 TD?
:twisted:
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Just thought I'd show this picture of someone else's VNT:
http://www.teamkorhonen.com/~dbwarrior/peugeot/turbo%20002.jpg
The entire vacuum actuator was swapped to a regular boost actuator. If you look closely you'll see a weld on the lever.
I don't have any further details, other than reading that it "works well".
If I get a VNT to experiment, I'll post details. fspgtd, your posts have been fascinating.
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hmmmm now where the heck can I get me a VNT for my 1.6 TD?
:twisted:
I can get a few VNT-17s off Euro PD150 TDIs. Less than 10,000km and costs $400 USD each, thanks to high shipping costs but it is still relatively inexpensive compared to other turbos. If we get a group buy going and import a few turbos at the same time, then we can save a bit on shipping.
Last year I sold my VNT-15 (identical to fspGTD's) from a 90HP ALH TDI with 70,000km for $350 USD in cash 4 days after I posted the ad.
The VNT-17 also has a casted in exhaust manifold, nearly identical to the VNT-15. The weight is 9kg per turbo+manifold.
It should be important to note that the VNT-15 and VNT-17 will not clear the rear motor mount in MK2s and MK3s. MK1s like fspGTD's Rabbit has a passenger side mount instead of a rear mount, so VNT fitment isn't a problem for them. Here's a picture of a VNT failing to clear a MK3's rear motor mount :
(http://pics.tdiclub.com/data/500/8936100_3117-med.jpg)
Modifying the rear mount can be done, of course.
There are many different VNTs at ebay.de (use search keywords "turbolader" "TDI"), some of them have detachable exhaust manifolds that also make the turbo sit higher, clearing the rear motor mount.
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Any update of the beast Jake ?
Marc/
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According to the FedEx delivery tracker, it looks like the wastegate arrived in a distribution center in kent, wa this morning, which is less than an hour's drive away. I think it might arrive tomorrow or maybe even later today! :)
I will probably begin installation work later this week. The first thing I will need to do is hold the wastegate in position in the engine compartment and determine if its exhaust should be coupled into the downpipe, or left as a separate dump tube. Then I will have to track down some materials probably (IE: stainless tubing and possibly a flex bellows, etc.)
I am leaning toward coupling the wastegate exhaust into the downpipe, rather than making its own separate exhaust dump tube. Does anyone know if a stainless flex bellows is required for coupling the wastegate exhaust to the downpipe, even if the tubing run was pretty short? I understand the bellows is to allow the tubing to expand and contract separately from heat cycling.
Dad drove the Rabbit with the turbo for his first time yesterday. He seemed pretty pleased with it, although I don't know if he realizes how much performance has been temporarily "sacrificed" with the reduced fuel. He may have a surprise after I install the wastegate and turn the fuel back up to stock 1.6lTD specs... I've also been driving it around a few days now and found it to be realiable, so I told him to go ahead and drive it home.
Edit: Pics to entertain you guys while we are waiting for the wastegate to arrive...
car shot:
(http://www.imagestation.com/picture/sraid170/p82239804f3024120492e249810157d51/f3fff96b.jpg)
engine compartment shot:
(http://www.imagestation.com/picture/sraid170/p77408fe980cfe69546478fa394bdc956/f3ffffbe.jpg)
air cleaner & boost tube close-up:
(http://www.imagestation.com/picture/sraid172/pda9a0562d7c04c8460faef8dd768a040/f3cbff69.jpg)
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Wow, that Rabbit is super-stupid clean! I wish my Rocco was half that clean, then I'd have a lot less work to do! :) She looks great.
Brendan
84 Scirocco 8v
00 Camaro L36 M49
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Jake... FWIW, as you might know, the five-cyl turbo (gas) Audi's had the accordian (bellows) on the wastegate that you're refering to. I couldn't find a pic of the normal 5000 turbo type that I have, but here's one that similar (not my pic by the way):
(http://www.hostdub.com/albums/veeman_album02/audi_Downpipe_02.jpg) (http://www.hostdub.com/veeman_album02:audi_Downpipe_02)
These pieces are stainless and I can confirm that the wastegate definitely dumps back into the exhaust via another tube. The one pictured looks a bit bigger in diameter than the one on my engine. I'd guestimate it's probably 1.5 inches or so in diameter.
I probably have one or two spares at home that I can snap more detailed pictures / measurements of if you'd like. It'd be great if one of those would work for your application.
Originally, I thought the accordian type piece was put in there to help with vibrations and possibly noise, but you're probably right about the expansion due to heat.
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Dad drove the Rabbit with the turbo for his first time yesterday. He seemed pretty pleased with it, although I don't know if he realizes how much performance has been temporarily "sacrificed" with the reduced fuel.
Install a tweaked pump and that thing would be stupid fast! I dare say faster than Dr. Diesel's car :lol:
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hey,
what kind of tubing/hose is that going from the turbo to the intake? and do you think it could handle 30 psi boost?
good job so far
Mark
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that tubing will easily hold 30 psi. It's only the connections I'd be worried about.
Looks like vacuum hose (flexible and its reinforced)
I just got an idea for intake tubing. Get the special hose for pool jets. That stuff is rigid and a little flexible (might even be what Jake used)
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Ok guys, the wastegate arrived! First reactions plus initial disassembly pics are in this thread: http://www.vwdiesel.net/phpBB/viewtopic.php?p=11567
Holding it in the engine compartment, it's a bit larger than I was thinking it would be, but I think it will still fit well. I'm going to fabricate a flange that adapts the EGR outlet to the wastegate bolt pattern and will bolt the wastegate directly to the EGR outlet flange. For the wastegate's exhaust, I am leaning towards mounting the wastegate so its outlet is toward the rear of the car, then having the 1.5" exhaust tubing bend downwards and welding on a section of stainless flex bellows (happend across a local source for this today...) and then I think I might merge it in to the downpipe right before the flex joint.
Veeman- Thanks for the pic of the audi wastegate dump tube. Wow, that wastegate dump looks nearly as big as the main exhaust out of the turbine outlet!
Mark and jtanguay - as previously mentioned, I used Aeroduct for the intake ducting. It seems to be often used on road race applications in larger diameters to get cooling air to hot brakes. But Aeroduct makes some nice quality ducting in four different styles and all kinds of sizes, which you can get from homebuilt aircraft suppliers. I found that it flexes very nicely, but does not conform to changes in diameter very well due to the spiral spring steel reinforcement.
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thanks for the info Jake!
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Started in to the wastegate mounting project yesterday.
Here is the space I have to work with... where I hope to have the wastegate soon occupying! :twisted:
(http://www.imagestation.com/picture/sraid172/pd109488865f60b562908de6601ef9dd9/f3c28322.jpg)
Unfortuntely, the bolt spacing of the VW EGR flange is narrower than the wastegate mouting flange. Wastegate is too fat to modify it to bolt directly up, so I need to fabricate a spacer that can bolt to the EGR flange and then have the proper bolt pattern on top to mount the wastegate. In order to recess the bolt heads holding the flange to the EGR plate down below the surface so they don't interfere with the wastegate, I decided to make the flange out of two pieces which I'll weld together. I can just use the flange that came with the wastegate for the upper piece, and for the lower piece I would get by just drilling and cutting it out of steel stock:
(http://www.imagestation.com/picture/sraid172/p203a6a276c150e1c3f1f6f0938827817/f3c28eab.jpg)
I am also having the flange rotate the wastegate as much as is practical to orient the wastegate exhaust towards the firewall.
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I got the wastegate mounted, and the without any wastegate exhaust installed, turned the fueling back up to stock 1.6lTD specs and took it for a first test drive yesterday. Pics of the wastegate install are to come later. :)
It looks like the wastegate is opening at 8 psi and regulating the boost solidly in the area of 8-8.5psi. With the fueling turned back up, the car is performing really well. Actually where I have the VNT adjustment set, I think the vanes are opening completely just below the 8 psi pressure where the wastegate is opening, so I think it is a great match. Upping the boost a little bit would beef up the on-boost HP even more, but as is, it is really fun to drive and has a usable, meaty and broad powerband. Although it was wet out during yesterday's test, I had to regulate the power in 2nd gear pretty severely to avoid wheelspin when the boost came on! :twisted:
Yesterday I also headed out on the freeway to do some high speed testing. Cruising steady on the freeway, the boost would sit around 4 psi or a little higher depending on speed and load. It seemed almost as soon as I mashed the accelerator pedal down, the boost would quickly rise to 8-8.5 psi and was kept there with little creep and no overshoot. I decided to see what the peak EGTs looked like so in a high speed 70mph zone, I floored it and watched the pre-turbine EGT gauge readout. The EGTs just kept climbing, although they really slowed down when the temps got high. I didn't count how long I tested, but it seemed like I had floored it for quite a while... when the EGTs got up to 1400 deg. F (and still climbing), I backed off. Without the piston cooling oil jets, I don't need or want it to get any higher than that - I will probably back off the fueling a touch to keep it safer (and maybe up the boost a little to compensate?) And by the way after running it hard like that, probably because the engine was hot, the oil pressure warning light and buzzer would intermittently come on when the RPMs dropped low, like during a shift. After some easy driving to let the engine cool off, I found the oil light and buzzer went out for good.
When the wastegate opened, it just made the engine sound change to be a bit more "rattly", but overall it was not very much louder. In fact I found you had to listen very intently to tell if the wastegate was open venting exhaust gasses or not, and I found it easier to tell it was working by just watching the boost gauge instead. (The behavior of the boost gauge is definitely different with the wastegate installed!) I was surprised how quiet the direct atmosphere wastegate vent was. After the test session, I found a evidence of the wastegate venting exhaust by a little bit of soot deposited on the firewall, but luckily, nothing else.
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A little extra boost on the same fuelling will reduce the EGT.
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A little extra boost on the same fuelling will reduce the EGT.
Run more boost! 8) Did you fit a proper FMIC on that car yet?
You will find that with increased fuelling, the WG will get louder and louder. A few months ago it was decently loud on my car, but now with a few extra pump mods, the WG sounds like a jza-80 Supra on the highway. It is not really annoying as it only really opens when you are really on it.
An interesting detail is I can "hear" how much fuelling I am getting by the intensity of the WG's sound pressure level. On cool or cold nights (rare anymore) the WG would be quite a bit louder, than say on a hot day after a semi long trip with hot fuel temps (lower fuel density). Certainly I am losing some mass flow from greater air temps, but with the >4" thick FMIC I am using now, post IC temps never stray far from ambient. In addition, after the massive FMIC install, the WG sound level increased dramatically as well... an indication of far better mass flow given the same boost :twisted:
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Here's a quick link to the specs for AeroDuct:
http://www.hrpworld.com/index.cfm?form_prod_id=310_3171&action=product
It says it's good for up to 550*F.
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Pics!
Wastegate mounting adapter flange:
(http://www.imagestation.com/picture/sraid173/p302a0ff88a7598eeeac4b911450bf29b/f3b58734.jpg)
...installed:
(http://www.imagestation.com/picture/sraid173/p9222a6feb1906df77fd5eac839a29fc1/f3b58b37.jpg)
-Wastegate air control-
Since the wastegate flows air to cool itself down, as recommended in the instructions provided, I used a 1/4" hose from the intake manifold. I decided sharing the small vacuum line that was used by the VNT controller, boost gauge, and LDA device would not be adequate. I decided to tap into the boss on the 1.6lTD intake manifold "El", and used one of the banjo fittings that came with the wastegate. By filing the boss surface flat, it would give a good sealing surface for the crushwasher. The banjo bolt required specialized M10x1.0mm threads however. I found a pressure plate to crankshaft bolt had the same threads, and was able to convert one into a tap:
(http://www.imagestation.com/picture/sraid173/p83f7d6e0cd785ed953f06a5ca08a34d0/f3b58619.jpg)
I hacksawed a couple slots into the end of the bolt (to give thread-cutting edges as well as make a space for the shavings to collect), and then to give the tap a more conical profile to help it get started easier and make it go in square, I pinched the four wedge-shaped pieces together with vice grips, following up with a thread file to clean up the threads afterwards. Going into the relatively soft aluminum, it worked quite well!
Wastegate air controls completed:
(http://www.imagestation.com/picture/sraid173/p6a98f58bbb5226579ef457c0b23b280b/f3b58ae8.jpg)
And in this shot you can see how the wastegate mounts with the adapter and also its air control hooked up:
(http://www.imagestation.com/picture/sraid173/pb863e2c6729428bce89db33854f8a88a/f3b58ba8.jpg)
I also found and fixed a fuel leak coming out of the input shaft by replacing the o-ring inside. When I had the governor cover off, I replaced the intermediate governor spring with a shim. The idea is to keep the main governor spring revv limiter working at a stock RPM limit, but keep the fuel pumping out at full amount all the way until the revv limiter kicks in.
The wastegate still needs an exhaust. There is an atmospheric dump tube that was supplied with the wastegate that almost fits! It might actually work with a little modification.
2383 - That "wastegate sound" load sensor sounds pretty cool! :P
I did try upping the boost today by stretching the wastegate spring. But I found that didn't work, because even after I successfully stretched it a bit, I found it relaxed to its original free height after being coil-bound. Adding a dial-a-boost would make it adjustable, but would add unsightly bulk and complexity. Changing the spring would be the simplest and cleanest way to increase the boost. Right now it seems I have the .6 bar spring. I am looking at springs in the range of .8 bar - 1 bar.
Also, recall this is my dad's daily driver. My main task at hand now is completing what I've started with this project, so dad can get back to driving and enjoying his car again. Taking on an intercooler install project is tempting, but is not going to happen right now as it would take the car out of commission for quite a while, and also there is not a budget for it at this time. An intercooler is the obvious future performance upgrade path though! :P
TDImeister - there are certainly are times when adding more boost pressure while holding fueling level constant can cool the exhaust gas temps, however, as a rule, I don't think it is necessarily true. For example, if fueling was already richened beyind the smoke point, extra boost pressure may result in more fuel being combusted, which would release more energy and heat into the combustion chamber than the extra air mass could cool.
Also, even if the engine is running lean and efficient, doesn't it still depend on some other factors? It seems especially for a motor that is non-intercooled and also where the turbocharger was approaching an inefficient operating area, that the added heat from additional pre-turbine backpressure and intake air temperature from the extra boost pressure could more than offset the cooling effect of the extra air mass.
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even tho' you have added a lot of extra fuel, adding boost will cool it. I had the 1.9td running 1300 at 8 psi. I installed a bleeder on the wastegate line, and adjusted to 12 psi. Max egt droppr to 1100, and it takes longer to get that hot, AND it makes MORE power, because it's burning the fuel more completely. Next , it's intercooled. Acutally, next it gets driveshafts and brakes and stuff, but the next performance mod is the intercooler :D
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Everything looks great Jake. Depending on what boost level you want to run, I would suggest a spring that is rated ~3 lbs less than what you would like to run, and your favorite boost controller. The controller can be a simple ball and spring type, or any of the electronic controllers. Yes, they all work well, and yes they make a difference.
On one of my cars, I have a Tial 46mm that had 2 springs in it from the factory; a 1 bar and 0.3 bar springs respectively. I found that I had much better overall control, and more power and tq (read from the dyno), when I removed the .3 bar spring, and ran the 1 bar in conjunction with a boost controller. The same maximum boost level was maintained before and after for reference. This same technique has also been observed with my diesel which also runs an external gate, as well as every other car I've tuned 8)
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TDImeister - there are certainly are times when adding more boost pressure while holding fueling level constant can cool the exhaust gas temps, however, as a rule, I don't think it is necessarily true. For example, if fueling was already richened beyind the smoke point, extra boost pressure may result in more fuel being combusted, which would release more energy and heat into the combustion chamber than the extra air mass could cool.
If you're teetering on either side of the stoichiometric fuel air mixture, then that statement would be correct. In this case, peak combustion temperature occurs just slightly on the rich side of stoichiometric, which not coincidentally is where maximum power is made. However, this is a gasser paradigm, because even when operating at the smoke limit, Diesels are fuelled much leaner than stoichiometric overall. And even at the smoke limit, the A/F ratio in a Diesel might exceed 18:1 or more (stoichiometric A/F mixture for Diesel fuel is very close to gasoline at ~14.5:1), and combustion efficiency is at a very high level -- over 90% -- so in the bigger scheme of things there's not much "heat" to be gained by, say, burning the addditional 10% of the uncombusted fuel. A plot of flame temperature versus A/F ratios (which is largely indenpendent of the fuel used), shows a very similar bell-shaped pattern, with the peak just slightly rich of stoic and rapidly falling off on either side.
Lean mixtures do not increase peak temperatures as much as they cause end-of-cycle temperatures (i.e. EGT) to be increased because of the slower rate of combustion. Again, however, this is generally a gasser paradigm. Diesel EGTs don't spike up when idling, when it's operating on a 100:1 A/F mixture.
The key thing here is that increased boost increases the charge air mass. The added mass, even though it goes unreacted with the lean fuel mixture, acts as a diluent. It is easy to illustrate the effects of increased charge air mass on temperature for a fixed heat input via the First Law of Thermodynamics:
Q = mC(ΔT)
If the energy input (Q) is held fixed (i.e. constant fuelling), and charge air mass m is increased, ΔT must be reduced to balance the equation because the specific heat capacity C is relatively constant for the purposes of the simple analysis.
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But the catch is that the energy input is not held constant. The temperature of the air mass itself increases because 1) the gas is compressed (ideal gas law, Pressure*Volume=nRT where R = universal gas constant = 8.3145 J/mol K, n=number of moles, and T=absolute temperature) and 2) the turbo is approaching the limits of it's efficency envelope.
Ray
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But the catch is that the energy input is not held constant.
To the extent of the limits of reasonable simplifications, it is, providing the fuelling is held constant. An increase in temperature due to the greater compression by the turbocharger is not accounted for in a First Law analysis as a heat input. For sure, the temperature and pressure at the end of the compression stroke is higher as a result of higher boost pressure. But this is not a heat input in a thermodynamic sense.
The temperature of the air mass itself increases because 1) the gas is compressed (ideal gas law, Pressure*Volume=nRT where R = universal gas constant = 8.3145 J/mol K, n=number of moles, and T=absolute temperature)
Actually, during the compression process, the state of the air follows (T2/T1) = (P2/P1)^[(k-1)/k] = (V1/V2)^(k-1) for an ideal adiabatic case, where k is replaced by the polytropic exponent n for a non-adiabatic process. where k > n :wink:
2) the turbo is approaching the limits of it's efficency envelope.
Actually, it can be shown that a VNT15 operating at 8 PSI of boost (PR = ~1.5) and air flow of about 9-10 lb/min. (4.2 kg/min) -- to simulate the VE of a 1.6L engine @ 4000 RPM or so -- is actually not operating at the peak efficiency island. This turbo has tons of head room for a 1.6L application that would run double the boost of what Jake is currently running, to 6000 RPM. That's why I have to laugh at people who want to put even bigger turbos into a 1.6
(http://dave-oh.com/pics/tdi/VNT15_map.jpg)
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Jake, I think 12 PSI is a nice number to try :) Let's see what the EGT numbers show then.
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TDIMeister - Actually I agree with that if I were to modestly increase the boost pressure on the Rabbit VNT, that it might cool down the EGTs. In fact I found from experiementation on my GTD Autocrosser 1.6lTD rabbit (with stock turbo) that increasing the boost pressure cooled the EGTs, although that vehicle had an nice, efficient intercooler, which I found helped cool the on-boost EGTs by a great deal - more than 100 deg. F cooler at 14 psi.
Even a 100% efficient compressor as it compresses air will still add heat to the intake air. Without an intercooler to get rid of it, the added temperature will consequently "linger" inside the engine through the intake, compression, and power strokes.
And the power to compress the air comes from a pressure drop across the turbine. Additional pre-turbine backpressure means additional pressure and temperature inside the cylinder during the exhaust stroke. This added temperature and pressure present inside the cylinder during the exhaust stroke cannot be removed even by the most perfect intercooler.
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Jake, you're correct.
I was not aware that this car you're working on is not intercooled. My bad. Certainly adding an intercooler alone could account for a 100+ degree EGT reduction even on modest boost levels.
Regarding the boost being generated via a pressure-drop across the turbine, corresponding to an increased exhaust manifold backpressure, you are correct again, but I would just add that the relationship is not 1:1, but it can be shown that it is a function of the total efficiency of the turbocharger, and on an SAE paper on the development of the TDI engine equipped with the VNT15 turbo, it is said that in certain operating conditions, the boost pressure actually exceeds back pressure.
If the turbocharger can be made to operate at a more efficient point, then the boost/backpressure balance becomes more favourable. Currently I plot the best efficiency point for your engine's operating parameters at around 70% (which is still pretty good by most accounts). Running at a higher efficiency point of, say, 74 or 76% will result in an increase in the density ratio in greater proportion to the pressure ratio, and adding a high-effectiveness intercooler will provide even greater benefits in reducing thermal stresses and EGTs.
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OK guys - I've got a new project update! I finished installing the pro-vent and the wastegate atmosphere dump tube. So all the basic pieces are now done. It is complete! But might there be in store for the future some more high-po tweaks to this vehicle? :shock: We'll have to wait and see!
wastegate dump tube:
(http://www.imagestation.com/picture/sraid173/p5ef490a1615fb593b7127dcb4594a8b1/f3affa05.jpg)
installed:
(http://www.imagestation.com/picture/sraid173/paee76af6984fa9d4684cb89673d619cf/f3b016d4.jpg)
(http://www.imagestation.com/picture/sraid173/p1f36735284cc1e97858f4eaae80a1135/f3b016ea.jpg)
There is also a pic and some details of the provent install here:
http://www.vwdiesel.net/phpBB/viewtopic.php?t=1490&start=24
Driving the car, it seems transformed for the better after the removal of the governor intermediate spring. When the RPMs reach a certain point, it seems like the car just keeps pulling without stopping! It just has this really nice, usable power band! Dare I say, with the VNT on the IDI diesel combined with the intermediate spring removal governor mod, this seems like the widest powerband of any turbo-diesel I've experienced. Better than a stock 1.6lTD or VNT TDI or even my lightweight, 6000RPM-revv limited 1.6lTD autocrosser! The powerband seems great for lazy shifting and is a perfect partner with the 4-speed transmission!
I hope to G-tech the car in the near future! Will see if I can come up with some power versus RPM plots and/or maybe some acceleration times...
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That's super cool Jake. Talk about a "happy fathers day" present! Your Dad's now got himself one sweet ride, a little grocery-getter rabbit with some sleeper suprises! Any guesses on MPG yet?
And she's running no intercooler, basically stock pump save the govenor mod, and "modest" boost. So with a tweaked pump, intercooler, more boost... you'd have a tire-melting monster! Hmmm... :twisted:
Anyone want to make bets on what kind of power it's putting down right now? :)
Brendan
84 Scirocco 8v
00 Camaro L36 M49
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If it's got an otherwise stock 1.6 TD pump, I'll start the wager at around 70 hp :)
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OK guys - the initial test results are in!
Brendan - yeah this thing is a sleeper. No outside hints distinguish it from a lowly 52 crank hosepower 1.6l NA! 8)
TDIMeister - if your 70hp guesstimate is wheel horsepower, I'd say you are right on.
To start off, I weighed the car at the local dump: 2140 lbs w/ driver and 2/3 tank of fuel. Since I weigh about 150lbs, the car without anything inside it and a dry fuel tank is definitely less than a ton.
I G-tech'ed five HP and torque curve test runs. I threw out one where the power was "off" (I think it may be something heat related - either hot fuel, or air intake) The other 4 results are plotted below. Note that these results are uncorrected, although I figure that the dyno correction factor during the tests was .997 (very close to 1).
(http://www.imagestation.com/picture/sraid173/p36c1068d1b5bc8c8876283cf98a3aa57/f3aaf231.jpg)
Keep in mind these are G-tech figures - different from chassis dyno results in that there are aero drag losses. These figures are not bad at all! To compare with a stock 1.6lTD, check out the fist post on this thread (thanks malone!): http://www.vwdiesel.net/phpBB/viewtopic.php?t=1352
The peak hp of the 2nd gear runs was 61.6-64.3 hp @ 4250-4300 RPM. Peak Torque of the 2nd gear runs was 88-91 ft-lbs @ 2600-2700 RPM.
All the runs were done in 2nd gear except for the blue plot, which was in 3rd gear. I kept mainly to 2nd gear because the speed range was much safer for the zone (25mph) I was doing the tests in. 4500 RPM is 42mph in 2nd gear, but it is 70mph in third! :lol: Anyway the extra aerodynamic drag in 3rd explains why the horsepower figures for the blue plot are lower. But also notice on the 3rd gear run because I shifted straight from 1st to 3rd the engine was tested in a lower RPM range, and also with the extra load you can see the turbo had more of a chance to spool up making more torque right above 1500 RPMs.
Although the VNT is already putting out a beefy torque band noticeably extended into the lower RPMs versus say a stock 1.6lTD, I think it is capable of being tuned for even more torque down low, since on this iteration of how it is set up, it starts closing the vanes probably as early as only 3 or so PSI.
I also did one quarter-mile acceleration test on a long flat stretch. For whatever reason, subjectively, I wasn't happy with how the power felt on this test, IE: engine power seemed "off". I think since I was idling it for a while at a stop before I launched, it might have heat soaked a bit. Also I got a little excited and chirped the tires both at launch and on the 1-2 shift. :oops: Probably doesn't help that these are only 5" wide rims! :lol: So anyway it definitely has more potential at current state of engine tune, but the results should at least be "ballpark" of where the car is at right now:
1/4 mi: 17.2s @ 77.7mph (OK, not stellar though...)
60 ft: 2.52s (this probably isn't too great...)
0-60: 9.85s (under 10 seconds... :P Cool!)
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TDIMeister - if your 70hp guesstimate is wheel horsepower, I'd say you are right on.
Yes, my assumption was based on whp 8) realizing that the method of testing would be either a G-tech or a chassis dyno, and I am not a fan of correction factors and driveline loss calculations, which I feel are often applied too liberally.
That is a beatiful torque curve, Jake. What impresses me is the so-called 80%-rule, which looks at the RPM spectrum at which 80% of peak torque and 80% of peak HP are produced, and the RPM ratio relationship of the two peaks. By eyeballing your graphs, it appears to me that you have at least 80% of peak torque between 1500 RPM all the way to redline, and 80% of peak HP from 3000 RPM onwards, and the RPM spread from peak HP to peak torque is 1700 RPM or a ratio of 1.65 (4300/2600). From an engine benchmark standpoint, those are AWESOME numbers!!!
Congrats on the pioneering work! I look forward to seeing what your next plans are for this engine!
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TDIMeister - if your 70hp guesstimate is wheel horsepower, I'd say you are right on.
Yes, my assumption was based on whp 8) realizing that the method of testing would be either a G-tech or a chassis dyno, and I am not a fan of correction factors and driveline loss calculations, which I feel are often applied too liberally.
That is a beatiful torque curve, Jake. What impresses me is the so-called 80%-rule, which looks at the RPM spectrum at which 80% of peak torque and 80% of peak HP are produced, and the RPM ratio relationship of the two peaks. By eyeballing your graphs, it appears to me that you have at least 80% of peak torque between 1500 RPM all the way to redline, and 80% of peak HP from 3000 RPM onwards, and the RPM spread from peak HP to peak torque is 1700 RPM or a ratio of 1.65 (4300/2600). From an engine benchmark standpoint, those are AWESOME numbers!!!
Congrats on the pioneering work! I look forward to seeing what your next plans are for this engine!
Ya, I was going to comment on that too. ANY engine builder in the world would kill to have a torque curve like that. You were right about it matching up with the 4-speed well. Even with an added intercooler you'd have more peak hp and torque, but with the same long flat curve. That's killer. I dont think the TDI's can sustain torque that long!
Gives me plenty of ideas for my project...
Brendan
84 Scirocco 8v
00 Camaro L36 M49
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[...I am not a fan of correction factors and driveline loss calculations, which I feel are often applied too liberally.
I thought there might be interest to discuss a lengthy missive I posted a while back about the prevailing method of applying driveline loss calculations, that is, a fixed 10-15% figure.
http://forums.tdiclub.com/showflat.php?Cat=0&Board=UBB4&Number=708003
I suggest this whole thread be archived :)
Hope I'm not hijacking your thread, Jake. :oops:
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I also find it interesting to compare the 1.6VNTD dyno results to my Rabbit 1.6lTD autocrosser's:
(http://www.imagestation.com/picture/sraid77/p57536b6dd032297329606ee82e2f4f6d/fb402251.jpg)
The GTD autocrosser has a bunch of differences... < 1800 lbs, different gearing... but probably most relevant influencers to the dyno plot are it has the factory Garrett 1.6lTD turbo with factory 9-10 psi boost pressure (as required by the racing rules), more fuel injection mods, and an intercooler.
Taking a closer look at the RPMs, the 1.6VNTD has more torque than the 1.6lTD in the 1500-3000 RPM area. When the factory 1.6lTD Garrett sleeps, the variable nozzle turbo is awake!
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I originally started this thread to determine whether it would be feasible to adapt a VNT turbo to an IDI VW Diesel to work without an ECU. I think that is pretty well established now. Although I don't have any reason to think the fuel economy would be bad, (in fact I think it is actually going to be pretty sweet), the car currently has an odometer in need of repair. Once that gets fixed and I hear some preliminary fuel economy data, I will relay the numbers up here.
I am also glad to hear that many of you guys have found my postings beneficial. The benefits have been mutual! Thanks for all the collaboration work from you guys.
To answer the question of what other future modding plans are in store for this car, look to other threads on this board. Hopefully in the not too distant future!
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I think I solved the oil light/buzzer problem. I found that an '84 1.6lTD used a different high-pressure oil switch on the oil filter stand than the '84 1.6lNA. It turns out that the TD switch is rated at a lower 1.4 bar pressure, versus the NA switch, which is 1.8 bar. I swapped the 1.8bar switch for the 1.4bar on the oil filter stand, and on the first start I noticed the oil light went out immediately (it used to require a little revving to go out). Driving it around, I haven't got it really hot yet, but so far seems to be working properly.
Edit: I also got the odometer repaired. I performed Roger Brown's trick (http://www.4crawler.com/Diesel/CheapTricks/Odometer.shtml) of drilling out the center of the broken plastic odometer gear slightly so it is not as highly stressed when pressed over the shaft, and I also used plastic epoxy to repair the cracked gear. The repaired gear seems to be holding up well so far.
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Hello.
Your vnt project looks very nice!!
Here some information (http://www.netikka.net/vepiku/jenkki.htm) about my Vw 1.6d vnt engine and car. whole homepage (http://www.netikka.net/vepiku/)
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Jetman - welcome to the GTD forum! Your car looks awesome, even though I can't read the finnish I enjoyed looking at the pictures. Thanks for the link and it's good to meet you!
I see you swapped VNT controllers to some pressure-actuated version... looks like a custom mounting bracket?
(http://www.netikka.net/vepiku/vntturbogallery/images/9.jpg)
And impressive custom exhaust manifold - wow! :shock:
(http://www.netikka.net/vepiku/pakosarja/hitsattuna.JPG)
Did the long-runner exhaust manifold make a performance difference?
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Finally I got my VNT running. I have followed Jetmans and fspGTDs projects from the beginning. Both have been very intresting and seems to work well.
I still have some learning with the boost controlling. I used the stock vacuum box with flipped internals. I haven`t got boost under 1,6bar (23psi) I think I have too stiff spring in box.
I have got better gTech results than Jetman, but I don`t think I have even close to 160hv what he has. I have stock and loose suspension, that must give me better results. 0-60 7,5sec, 1/4 mile 15,8 and 141hp by the gTech.
Pics (http://www.kotinet.com/matti.farm/Audi/)
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..
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Beautiful install, Audi80!
http://www.kotinet.com/matti.farm/Audi/114-1483_img.jpg
By the way, that is an interesting exhaust tip. :wink:
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Dynoed today. 151hp/286nm at wheels. That`s ~165 crank hp 8)
http://www.kotinet.com/matti.farm/117-1746_img.jpg
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Dynoed today. 151hp/286nm at wheels. That`s ~165 crank hp 8)
http://www.kotinet.com/matti.farm/117-1746_img.jpg
Could you give us some more details on this car? :)
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1.6 CY engine, mechanical head, little porting with bigger valves. VNT20 with tube header, 2,5" exhaust, gasser intake manifold. 10mm pump and 28psi (1,9bar) boost. Pictures are couple posts above.
This is pretty much all you can get with 10mm pump.
By the way, that is an interesting exhaust tip.
Didn`t want to show big exhaust tip, those are for teenagers :wink:
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My new engine project
click (http://koti.mbnet.fi/vepiku/remontti/)
click 2 (http://koti.mbnet.fi/vepiku/14.8.2005/)
click 3 (http://koti.mbnet.fi/vepiku/19.8.2005)
click 4 (http://koti.mbnet.fi/vepiku/20.8.2005)
Welcome 8) (http://www.jl-import.fi/phpBB2/viewforum.php?f=15&sid=17870204be1a2a9ed66b0dcda8b7abe5)
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I saw some 3 piece thrust bearings. 1st click third picture up from the bottom.
I've heard of them tearing up cranks. Getting off the VNT topic but had to mention it. Ooops, it's the 1 piece thrust bearing that messes things up.
Great pics. Nice car for your new engine.
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Phat ride.. but you need to clean the enginebay to match the outside a bit ;)
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The best method of control I've been able to come up with so far is to run an electronic boost controller like a Profec A as it integrates "fuzzy logic" and ought to be able to anticipate boost spikes and such. Instead of hooking it to manifold pressure, I would hook it to the vacuum pump.
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In defense of my VNT controller: it really did do everything I was hoping it might have: it gives excellent performance - both in terms of broad powerband and excellent throttle response (I believe superior than stock TDI, which lags for a split second after throttle application while the vanes close), and it gives good fuel economy (> 50mpg was measured on several consecutive tanks.) I am not convinced that a few pounds excess boost at lower throttle ranges (AKA "hyperactive" boost) is a bad thing. What happened after driving it more, was that you just get used to it boosting nearly all the time, and that it doesn't mean anything bad is going to happen. An unexpected side benefit of the extra boost with the efficient intercooler, was that it really helped the engine stay at very stable operating temps (in fact, the temp gauge was reading 2 "clicks" cooler than when it was naturally aspirated.)
One thing I also like about the mechanical VNT controller - is that like the engine it's attached to, it doesn't have any complicated electronics, wires, or sensors. There is something to be said about a self-contained package without even any lines from the vacuum pump even.
I agree it is important not to blow a boost tube with it though! That is perhaps its achilles heel, and it prompted a few precautions. For example, I proactively beaded every boost tube connection. I also tuned the fuel injection LDA to severely reduce fueling (more than a standard turbo-diesel) if the boost pressure drops. So the fueling is as boost pressure sensitive as I could make it.
I think every VNT-15 turbo installation has one or more potential failure modes though. The stock TDI setup can have the vanes stick closed and have the boost spike to very high levels. Since my design has a wastegate (not to mention the pressure relief valve, both of which were not present on the original design) I'm not too concerned about the vanes getting stuch closed from carbon build-up... or even the VNT controller catastrophically failing somehow! :lol:
Re: thoughts of your proposed setup:
* VNT in a vanagon 1.6lTD sounds like a great idea. The low boost will really help get the vanagon moving!
* If you want to run a full dose of fuel right up to the smoke level at your target boost pressure of 15 psi, a wastegate will be required.
* I can't think of any elegant way to implement a mechanical (IE: non-computerized) controller with all the inputs you describe.
* If you try something out, let us know how it works. Good luck!
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I sincerely wish you luck in coming up with an effective, safe, alternate design, and in executing it. This will however be no easy task.
But if you are not able to make the design foolproof, I'd advise you to not loose sleep over it as long as you are dealing with at least a half-intelligent driver. Why not worry too much? These VNT turbos are a lot tougher than you'd probably think from reading about the failures on TDIclub.
For our purposes, they only need to be tough enough to last long enough for the driver to notice the funny noises, sudden lack of power, "0 psi" boost gauge reading, and pull his foot off the accelerator and limp over to the side of the road or parking lot to check things out... as happened once when I blew a boost tube early on in testing.
The exact VNT-15 turbo used in this Rabbit 1.6D was previously misdiagnosed as a bad turbo when it was installed on a TDI. The boost controls were installed incorrectly by a VW tech, with full vacuum signal straight from the vacuum pump to vane control diaphgram, meaning the ECU boost controls were totally bypassed and the vanes were put in constant full closed position during operation. It was run like that for at least 2 test drives that I did myself, each of which eventually ended up with the engine going into a "limp home" mode only after several minutes of driving (the ECU was not quick to put the engine into this mode.) Each full throttle burst resulted in pulsation sounds coming through the intake, which I believe was compressor surge. Yet though all the extreme RPMs the turbo must have been turning to do that through those wide open bursts without a wastegate even to open and divert exhaust gasses around the turbine, the rotating parts held together and didn't instanteneously burst. In fact, they seem to be working as good as new now, happily boosting the 1.6 IDI motor. What I take away from this: is that I believe what kills these turbos is when they are run at too high RPMs for too long of a long period of time, long enough for the metal to failure from cyclic fatigure (aluminum in particular has a particularly low resistance to this kind of cyclic fatigue abuse.) I think the wheel burst failures we read on tdiclub about must have been the result of the turbo overspinning for a quite extended period of time.
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well time to bust out the rpm sensor for the turbo! just add another tach to your dash :lol: problem solved!
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Hi,
Have found this thread through the TDI board, very interesting reading!!
I am also carrying out a VNT conversion at the moment and have gone through surprisingly similar processes and problems!
Libbypapa re. your poste above:
"The control system I imagine for the vanes would be as follows.
I would first have the vanes be normally open (spring pressure).
I would have a throttle arm controlled spring to exert pressure to close the vanes. I would run another cable off the trottle arm, to a spring at the vane control. Whenever throttle was increased it would increase pressure to close the vanes.
I would add a control that would be rpm dependant. With increase in rpm, there would be an increase in pressure to open the vanes. I am toying with the idea of using a vacuum diaphragm from a cruise control unit. I imagine that engine vacuum could be used to control the diaphragm. Hopefully, a happy relationship to the three controls could be found. I am wondering if vacuum from the vacuum pump is linear with rpm.
I imagine that I would still want to use a wastegate system from the EGR port similar to the one you used in order to control boost spikes.
I imagine that the control system outlined would have the effect of keeping the vanes open when not demanding more boost (in order to lower EGT's, and increase engine efficiency), eliminate the hyper boost response at cruising, and be far more likely to fail to a safe(er) mode (vanes open). "
There is no boost dependancy here so the system has no feedback for such things as air temp, altitude or any other factor that a pressure referenced actuator accounts for. Also the 3 springs would have to be so accurately balanced to get the correct boosting characteristics that it would be almost impossible! Remember you would have to include the forces exerted on the turbo vanes by the flowing air in your calculations, which measuring would be no mean feat in itself!! You are talking carburettor style accuracy!
The rpm dependant method may yeild VERY strange boost characteristics, as although airflow into the engine may be linear with respect to rpm, air flow accross the compressor is not proportional to these for the boost curve. An engine load referenced spring may work better.
How can a cruise control work? There is no engine vacuum on a diesel?
Also, the problem of the turbo overspeeding if a boost hose blows off is alot less catastrophic than if the vanes stick closed when the boost hoses are still on! Zero p2 pressure means that the compressor wheel has effectively no forces accross it and as such is in no danger. The problem is that the shaft speed may become high enough to cook the bearings or wobble onto the housings at either end. This will NOT happen after 5 secs (at most) before you notice you have popped a hose! In fact last time a hose popped at full boost myself and passenger actually noticed quite quickly, it was apparrent by the huge !!POP!! (and passenger cursing) that nearly made me swerve into oncoming traffic!
FSPgtd:
Have to say that your setup is looking pretty sweet, and such nice fabrication on the exhaust!
I had designed a very similar setup to yourself, although the only extra trick i am using is a ballvalve connected to the throttle arm that allows vaccum from the servo to pass to the -port on a 2 port actuator when the throttle is closed, meaning that when the throttle is closed beyond a certain point, the VNT vanes will be opened, allowing less backpressure at idle. The ball valve has to be completely closed at cruise speeds however as this loses too much driveability.
It also means that when you lift off suddenly or brake the vanes open up. This gives a slight lag, but nothing like a normal turbo, and avoids using the compressor past its surge point. Have you compared your boost at certain rpm’s to the flow map for the GT15? It may be producing boost at the wrong point (but probably not by the sounds of how well it is running!!). There is a map here: http://not2fast.wryday.com/turbo/maps (very good site) or try http://www.turbobygarrett.com/turbobygarrett/products/turbochargers.html if you have the part number (vnt has a slightly different comp spec to wastegate GT15).
There are so many adjustment points now though that testing is becoming a heavy task!
There is:
1) Vnt start point adustment (on threaded rod)
2) Vnt finishing point (small allen stop on turbine body) (gt20)
3) Bleed valve to boost + side of actuator to determine vane movement (boost) curve
4) Ball valve active point
5) Thinking of installing another bleed in the vacuum line to see if can use more proportionally!
A better solution to the economy/overboost situation may be to use a tps module (or similar potentiometer) on the throttle arm that will vary voltage output for different throttle openings. This can then be used as an input to a small circuit to control an amal solenoid bleed valve (through PWM) connected to the vacuum side of the 2 port actuator. Maybe a very simple digital boost controller uses this same circuit (in reverse)?
Anyway, very interesting reading guys, will keep following this one!! :D
Cheers
Greg.
Citroen ZXVNTD (GT20)
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Greg - interesting idea about using a ball pneumatic valve to add some throttle control to the VNT system. Do you have any pictures of your ball valve installation and/or throttle linkage?
In this thread we discussed compressor maps (including the VNT-15) and how well they match to IDI engines:
http://www.vwdiesel.net/phpBB/viewtopic.php?t=1576
Driving the VNT Rabbit, which is actually tuned to deliver less boost pressure than it delivers in the stock TDI application I believe, I have not heard any sounds of compressor surge. I also know the sound of a surging VNT turbo because I've heard it when driving an A4 Golf TDI before. This particular car had it's VNT controller incorrectly hooked up to full vacuum position (this was the local VW dealership's fault), and the sound it made I would describe as an odd, shuttering "sh sh sh sh sh...." whenever the throttle was quickly lifted after brisk acceleration. It didn't hurt the turbo though. I think they are a lot more durable than most give them credit for.
I am also kind of in denial about whether there really is any problem with leaving the vanes closed. If the added load were significant, I'd think the engine RPMs would drop when the vanes were flipped from open to closed at idle, and I don't remember the RPMs changing very much when I tried that. The extra airflow even at low/partial loads might actually help aid in combustion efficiency. Also, any energy recovered from the pre-turbine backpressure in the form of boost pressure would be returned to the crankshaft on the intake stroke. The only efficiency "loss" would be that energy lost to the turbocharger's aerodynamic/mechanical inefficiency. The VNT turbo is pretty efficient, I think. If the VNT 1.6lIDI Rabbit were not seeing as impressive fuel economy figures as it has shown (which are IMO, above and beyond what a "common" Rabbit 1.6lTD could do) I may be inclined to make a change, but it has just been excellent.
There is a small potential problem that the added boost from the closed VNT vanes could be hard on the headgasket sealing properly when the engine is cold. But I hope that a multi layer steel headgasket (in the plans next for this car) will address this reliability concern.
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i got a gt2052v wich came from a vag 2.5tdi v6.
i readed the whole topic,
but i am asking myself now,
can you use a VNT turbo on a TD, if you use a wastegate and control the vanes by pressure? will it work good, an most off all, is the job worth it?
tnx, greetz, Benjamin
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So Hows the long term on the VNT rabbit? Any updates?
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rode in a vnt caddy today, but he just has vacuum applied from the brake booster, so it's always shut. unfortunately i couldn't talk him into disabling the bov he's scured a little lol. btu man that thing builds boost like you wouldn't believe. he doesn't have any fueling mods and it spools faster than anything i've ever ridden in, it is almost instant lol. but then at 10 psi the bov wigns open and all you hear is woooooooooosh, if he stays on it he can bring the boost and hold 10psi with the bov open haha.
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thats kind of a bad setup. I think he is really overspeeding that turbo if hes just opening a dumpvalve and still hammers into it.... :? Cool post though.
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thats kind of a bad setup. I think he is really overspeeding that turbo if hes just opening a dumpvalve and still hammers into it.... :? Cool post though.
Yup, I agree. I'd be far more concerned about grenading the turbo just keeping the vanes closed and dumping through the BOV. Cripes, can you say pumping losses and overspeed turbo... :roll: The boost wouldn't kill the motor, its the shrapnel in the intake that might be a problem. Hopefully he has an intercooler that will catch the big pieces.
Andrew
I must be missing something, but, IMO, if he uses an external wastegate to control boost there would be no overspeed issue as once max boost is reached exhaust is let out of the exhaust mani so it doesn't go through the turbine wheel.
I plan on doing a similar system when I VNT my friends Caddy, vanes set partially open with a controller like "Named tintin" made and an external wastegate to set max boost.
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no they mean the bov on the intake. and yeah thats what he's doing, i'm trying to point him into the right direction of getting an external waste gate, since the only real way to control boost. the other problem like you all said is that it has vacuum all the time. but i think he's going to fix that
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Isn't there also the issue of too much exhaust manifold pressure which can cause the valves to float?