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Engine Specific Info and Questions => IDI Engine => Topic started by: subsonic on January 21, 2008, 09:14:07 am
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I was re-reading Maximum Boost by Corkey Bell this morning while sitting in the only room in the house where I can get some piece and quite.
I was looking through the section on wastegates. While an external is the best setup, the internal is in wide use. It appeared that the biggest detractor for the internal wastegate was the reintroduction of exhaust gasses back into the flow exiting the turbine, causing turbulance and affecting the speed of the overall gasses going down the DP.
Can an internal wastegate be modified so that waste exhaust gasses are vented into a seperate exhaust pipe, instead of back into the original stream?
As a additional question, There is a picture in his book of adapters that place the wastegate between the turbo and the manifold. Could this option be used to allow the use of an external wastegate on a internally wastegated turbo? The original wastegate would have to be modified so as not to open, but I belive this has been done before.
Thoughts?
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As a additional question, There is a picture in his book of adapters that palce the wastegate between the turbo and the manifold. Could this option be used to allow the use of an external wastegate on a internally wastegated turbo? The original wastegate would have to be modified so as not to open, but I belive this has been done before.
Thoughts?
I don't see why not. I was going to place an external wastegate between my VNT and manifold before I decided that it probably wouldn't be needed. I even bought it and had a plan to put it in my adapter that I made to fit the 3 bolt flange to the 4 bolt manifold.
Can an internal wastegate be modified so that waste exhaust gasses are vented into a seperate exhaust pipe, instead of back into the original stream?
Probably depends on the turbo, but I bet you could make a solid flange with an internal plate to separate the exhaust streams and route them to external pipes. I don't think it would be feasible on my k-14 as the wastegate was inside the housing and shrouded from what I remember.
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Much higher :) I think I will be able to go well into the 30s with mine with the porting on the 1.9 head, Giles pump IC and the 3"DP.
I was hoping someone had some info on routing the wastegate stream into a seperate pipe instead of back into the flow. Some internal wastgated turbo's can do this. I just did not know if it had been done on a T3 yet.
Manual boost controller will be a must, for sure.
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so trying to get more boost out of a t3. Disconected what i thought was the hose to the wastegate (internal) and the boost didn't change, still 10psi. Does the waste gate open a set pressure. My other t3 only goes to 8 psi Both vehicles have 3 inch down pipe with only 3 inch resinators, air intake is large on both with pod filters. Need more boost. Trying to tune to boost. No wastegate, just turn down the fuel if your scared. Its how all the oldtimers use to tune tractors for pulls 'round here. I eventually removed hose, cap both ends, still nothing
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It's a mater of the waste gate AND the fuel. More boost means more fuel.
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l) and the boost didn't change, still 10psi. Does the waste gate open a set pressure.
there is a pop off valve in the intake to prevent excess boost on stock cars in case waste gate sticks closed.
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No blow off on my motors. It not a lack of fuel. Have turned up fuel, it is definately the wastegate opening. The boost climbs fast on both these t3 motors and just stops at set points 8 and 11. Need to weld this thing up...
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So the t3 on the pickup is now running 25 psi. Hose disconected, and capped. The the jetta has the same turbo, only makes 8 psi. What the...? The waste gate can be frozen, i'd have boost. Don't understand, if the wastegate doesn't how much boost, how can it open a 8 psi?
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Perhaps it is time for the wastegate to be opened up for inspection. I have read some of the posts here about frozen or cruddy wastegates. They looked nasty. The seat that they seal on also gets way nasty looking. Andrew has cleaned the seat up before with a lapping compound I think. I would really like to take my wastegate apart for a inspection and cleaning. Has anyone removed the actuator and wastegate from a t3 before? If so I would appreciate some guidence on how to get it apart.
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Has anyone removed the actuator and wastegate from a t3 before? If so I would appreciate some guidence on how to get it apart.
I asked that question here (http://vwdiesel.net/phpBB/viewtopic.php?t=11730&highlight=) but got no reply. I'm starting to get a complex asking questions no one has answers to. :? :lol:
like: what does the return line from the waste gate do that goes to the bottom of the tubo inlet? keep oil in the intake or since it's in the throat of the inlet, provide vacuum to keep the waste gate closed?
I had my turbo off, soaked, cleaned, etc. There is a 5mm allen socket (if I remember correctly) on the waste gate valve, used that to rotate valve around, back and forth, flooded the back side of the valve and no fluid came past. Used shop air to cycle the waste gate, repeated the leak test, no leaks, called it good enough.
Also check all intake hoses for splits. My TDi split one where you can't see it and had low boost around 10 or 12 psi max until I found it
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heres a good disassembly post for the k24
not exatly what you need but, maybe help a bit? 2nd or 3rd page i think they do the wastegate
http://vwdiesel.net/phpBB/viewtopic.php?t=1841&highlight=k24+assembly
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Here's a T3 with a better flow option for the internal wastegate.
http://vwdiesel.net/phpBB/viewtopic.php?t=3252&highlight=garrett+dissasembly
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Now that is very interesting. As a bit of humor, I am pretty tired right now, I read all the posts on the link like 5 times and was thinking"What the Hell is Andy2 talking about! No one is talking about what I am looking for."
Then I see it: :oops:
(http://www.imagestation.com/picture/sraid201/p7837a29df63900f7d251659654a52eca/f007e9b9.jpg)
I have not seen this type of down pipe before. Has anyone else? This is exactly what I was looking for. Proof it could be done. I dont need to have a converter on my exhaust, so I could just run a second pipe off the turbo, and just have it dump into the atmosphere a few feet away. Add a 2" pipe for the wastegate, man you would have 5" of exhaust coming off the turbo. Not much restriction there :lol:
How the hell do you redirect the wastegate flow out to the dump pipe???
Still looking for info on how to pull the actuator and wastegate for clean up, etc..
Thanks for the link flapjack. I found that one while searching a day or so ago. Good info to have on hand as I have a spare k24 sitting on the shelf next to the stock T3 and the Merc T3.
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I just checked the DP off my K24 and stock T3. Nothing looked like the above picture.
Since Jake is currently off line, does anyone know how his wategate setup worked?
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I agree. I have a T3 on my AAZ and also a K14 and a K24 here and some stock downpipes. I have seen nothing like this "dual" downpipe. What's it off?
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Since Jake is currently off line, does anyone know how his wategate setup worked?
if it was off his FSP Rabbit, like the post implies, then his waste gate would work like stock and he could not close the original opening in the turbo housing from the waste gate to the turbine exhaust.
What happens if you don't use a waste gate at all with a Giles pump? That would require the least amount of work. Didn't the GTD's run without a waste gate?
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It would seem kind of odd to have a wastegate open and have it dump out out two seperate locations.
The DP does not look very much like a custom fab piece. Perhaps it is and is was just done a long time ago. If it is a stock unit off of something, it would interesting to find out what it is from.
You can run with out a wastegate for sure. Im sure there are guys here who do. That would be the least amount of work. I plan on having one. I have ended up dumping WAY more money into this project than I had anticipated. When everything is all together and running, I plan on a very careful break in period. Boost and fuel will be going up in baby steps. I will eventually get it up to high performance stealth mode. I like to have a fall back or built in saftey position just to make sure.
When I jumped out of planes when I was in the service, the main chute was all I ever used. That was all I ever wanted to use. You can bet your ass though I always had my reserve strapped on. It's good to have a backup, just in case :wink:
I do not know about the GTD's wastegate setup. Perhaps someone else can chime in on that.
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That picture is a garret t3, stock one for these mk2's. I've done this a bunch of times, also routed it to the atmosphere instead of back into the downpipe.
All you need to do is remove that wastegate block off flange, make a hole the size of your tubing for the dump, weld up your dump tube, and than make a small block of plate and weld it into the turbine housing to completely divorce the wastegate stream from the downpipe stream.
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So says the man! Question answered :D
Thanks Dave.
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I've done this a bunch of times, also routed it to the atmosphere instead of back into the downpipe.
All you need to do is remove that wastegate block off flange, make a hole the size of your tubing for the dump, weld up your dump tube, and than make a small block off plate and weld it into the turbine housing to completely divorce the wastegate stream from the downpipe stream.
So here are some photo's of my turbine. Wastegate blockoff flange removed.
Where does the hole for the dump tube go? Is it in the original flange that gets removed?
Where does the block off plate go? Is it the slot that you can see in the 3rd picture? Any concerns about the block off plate weld in such a high heat area?
What the heck is that little hole in the turbine just under the wastegate valve?
(http://i239.photobucket.com/albums/ff120/subsonic44/DSCN0132.jpg)
(http://i239.photobucket.com/albums/ff120/subsonic44/DSCN0181.jpg)
(http://i239.photobucket.com/albums/ff120/subsonic44/DSCN0183.jpg)
(http://i239.photobucket.com/albums/ff120/subsonic44/DSCN0182.jpg)
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You would put the hole either in the plate you removed or in custom plate if you choose to go that route. Welding cast material is fairly tricky and is best done by someone who is experienced in the procedure. I weld a lot of turbine housings, never had a problem, but there is a process that goes along with it to ensure reliability.
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I was just asking so I could get the process figured out and visualize it in my head.
I have no idea how to weld. Me trying to do this would be a disaster :lol: Last time I was involved in welding I was helping a friend hold down a steel plate he was welding in place on a trailer. He was underneath, I was standing on top of the plate, pushing it down with my shoes. I was looking away so I would not go blind, drinking a beer. Bastard melted the sole of my boot and damn near set it on fire :shock: He started yelling when beer came dripping down between the plates as I dumped it all over my boot :lol: I will rely on the subject matter experts for welding right now, thank you very much :wink:
So when you block off the port that flows back into the main exhaust, are you doing it on both sides of the port opening? Wastegate and turbine side? There seems to be a few inches between the two. I am guessing that if you did not block off both ends you would have some pretty good turbulance. I am also guessing that if you blocked off the port opening in the turbine side, you would have a smoother (faster :twisted: ) flow of exhaust as it dumped into that sweet 3" stainless steel down pipe.
When you weld on the new dump tube, do you extend it through the plate and try and get it as close to the wastegate valve as you can, or do you leave it flush? Would it be better (if possible) to weld a connector pipe directly to the wastegate housing(inside it)? Something with a bolt pattern flange on the other end to connect the dump tube too? Would there be any benifit to that approach? Faster flow from not getting dumped into the old open section of the wastegate?
Last question :roll: he he
Why does a setup like this make the wastegate more accurate?
Corkey Bell writes:
"The value in creating a seperate tailpipe here is that it effectively increases the exhaust systems total flow area. In general, a wastegate will be more positive in response and somewhat more effective in controlling boost preasure when accompanied by it's own tailpipe."
I get the lower back preassure concept:
3"DP + 2" dump tube = 5"exhaust 8) ,
The flow will have less turbulance, but why does the wastegate now perform it's role better? (And what the hell is that small hole under the wategate valve? :? )
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Just read another interesting tidbit from Maximum Boost. Bell reccomended a turbo to manifold direct union, no gasket, if the metals are the same. Cast iron to cast iron. If both mating surfaces are milled perfectly flat and secured together with through bolts.
Thoughts on this?
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Just read another interesting tidbit from Maximum Boost. Bell reccomended a turbo to manifold direct union, no gasket, if the metals are the same. Cast iron to cast iron. If both mating surfaces are milled perfectly flat and secured together with through bolts.
Thoughts on this?
I mill them if they are out a bit, if I am in a pinch I use a gasket, never had any issues either way.
Yeah I usually weld both sides of the cross over port to reduce turbulence.
I weld the dump tube flush to the plate. There isn't any point in trying to get it close to the valve.
As for the small hole, don't know, where does it go?
The reason a divorced wastegate tube is better is that you eliminate the variable of pressure in your exhaust tract acting against the wastegate.
ie if you have a restrictive exhaust system the pressure in your exhaust could act against the wastegate tube and cause the wastegate gasses to back up and increase pressure which would make boost control a bit dicey.
If it is designed properly however you can actually get your exhaust system to scavenge from the wastegate.
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If it is designed properly however you can actually get your exhaust system to scavenge from the wastegate.
Know anyone who might be up to building a properly designed system :wink:
I should have the ATP turbo mani and the turbo in the mail up to you in the next day or so. I am going by my friends shop to pick up the turbo. I dropped it off after dissasembly so he could glass bead everything. Wastegate and accuator were removed as well. Since he does valve work, he is going to clean up the wastegate valve and recut the seat for a perfect seal.
Gpopshop told me to go ahead and glass bead blast the actual comp and turbine blades with 60psi. Jeez that makes me nervous. They look so damn fragile!
I told him to give the turbine and compressor housings hell with the glass bead, so they should be compleatly stripped and clean when you get them. As a matter of fact, everything will be except the center housing. My bud does not want to glass bead it :? . He says that it is next to impossible to get all the residue out when you are finished, and he is afraid it will wreck the turbo. It's pretty clean as is. I have had it soaking for like a month in cleaner. Just wanted it super clean!
Since the turbo is going to be balanced, and the turbine housing is getting Ceramic coated inside and out, I am going to send it up to you dissasembled.
Do you want the ATP stripped as well? I did not know if you had to do this before the ceramic coating was applied.
If you feel like putting down some molten metal on both sides of the cross over port, I could sure go for the seperate dump tube setup :twisted: . What size dump tube do you reccomend?
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I have not seen this type of down pipe before. Has anyone else? This is exactly what I was looking for. Proof it could be done. I dont need to have a converter on my exhaust, so I could just run a second pipe off the turbo, and just have it dump into the atmosphere a few feet away. Add a 2" pipe for the wastegate, man you would have 5" of exhaust coming off the turbo. Not much restriction there :lol:
How the hell do you redirect the wastegate flow out to the dump pipe???
Still looking for info on how to pull the actuator and wastegate for clean up, etc..
That looks like a "custom" modified pipe to me. I took apart a 1.6 T3 to figure out why the wastegate was sticking. I had pictures of it but I think they are gone now. :( I will try to describe it as best as I can. If you look at the "discharge" end of a VW T3, there is a plate with 4 bolts blocking the wastegate port, right next to the flange from the downpipe. You can simply remove this plate, and fab up a small 4-bolt flange to connect here to make your "dump tube". There is a small (very small!) passage from the wastegate dump to the main downpipe where in the OE configuration, the gasses from the wastegate join the exhaust from the turbine. This looks really restrictive to me and it can only help things by providing a free-flowing path for the gasses to escape. I wouldn't worry about sealing up the passage though, if any gasses go through it they will just join up with your downpipe. This was the plan on my TDI swap. The only reasoning I can think of to block off the wastegate dump in the OE configuration is because the wastegate valve is not a "flapper" like most newer turbos are, it is more like a valve in a cylinder head, so the gasses are not going to be coming out in a "straight through" path, so a need for the discharge being right in-line with the flow of the wastegate port is probably not as needed as it would be if it were a "flapper" type valve.
As for disassembly, try and work with me here, I will do the best I can to explain but it's hard without looking at it in front of me. :) On the top of the "can" of the wastegate, you can see the two pieces- the upper part fits inside of the lower part, and there is a small "lip" all around the inside of the can. If you look closely inside the lip, (there might be crud caked up in there, there was on mine) there is a big snap-ring looking thing. It's actually more like a piston ring, as it's spring-loaded and fits into a groove all around the inner part of the lower half of the can, holding the top part in place. If you look closely, there will be a taper on one end of the ring, small enough that it will take a pick or a very small, thin flat screwdriver to move it. Pull inwards on this taper, and the ring will slowly come out of the groove. Once the top is off, it's pretty straightforward. There is a nut on the top of the valve that releases the spring retainer/diaphragm assembly, (remember that 5mm hex on the bottom of the valve? You need to hold it on that end while you turn the nut on the top off) Be careful as it is under some spring pressure and it let go with a pretty good pop when I took mine apart.
Alas, the wastegate valve on mine is bent (someone must have dropped it) so I am going to see if a machine shop can straighten it, otherwise I'll probably need to find another turbo.
Hope this helps, sorry if I'm not real clear on my instructions. :P
Brendan
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Thats good stuff.
I did just that after I cleaned the top of the accuator off and saw the ring. I got it all apart a night ago. Having the valve and valve seat glass beaded and recut for a perfect seal. Will be having everything else cleaned and inspected.
I am positive you can pick up another valve if yours is bent. Is yours the flapper, or does it look like the one that is in the pictures up above?
Since I am going for a total rebuild I decided to have the studs replaced on the turbine housing. They were rusty and pitted. My friend got them all out except one. Thing snapped right off :x Had to drill it out and install a helicoil. Gonna have that area milled perfectly flat tonight.
I am wondering about going with stainlesss steel studs. I am worried about the cast iron expansion rate v.s the stainless rate. :?
Anyone go this route and have any thoughts they would like to share?
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Yeah, mine looks like the one above, just like a valve in a cylinder head.
I'm also stuck on mine, the compressor housing came off just fine, but the turbine housing is stuck good. ALL of the turbine housing to center section bolts broke on mine, and now that they are all out, I cannot separate the center section and the turbine housing. There is no good place to pry or whack with a hammer. :(
Brendan
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On the top of the "can" of the wastegate, you can see the two pieces- the upper part fits inside of the lower part, and there is a small "lip" all around the inside of the can. If you look closely inside the lip, (there might be crud caked up in there, there was on mine) there is a big snap-ring looking thing. It's actually more like a piston ring, as it's spring-loaded and fits into a groove all around the inner part of the lower half of the can, holding the top part in place. If you look closely, there will be a taper on one end of the ring, small enough that it will take a pick or a very small, thin flat screwdriver to move it. Pull inwards on this taper, and the ring will slowly come out of the groove.
Brendan
Hmm could the early to mid-80's waste gates just be crimped? Mine does not have anything resembling the snap ring you desribe, just looks to be crimped. :?
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Mine came apart when I started hitting it with a 3 lb mallet. I hit it in between wacks with the propane until it was smoking and to hot to touch.
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Got my turbo back from my friend with the bead blaster. Nice and clean :) Completely disasembled. Had the wastegate valve seat recut, wastegate valve recut. Some small cracks in the seat, but nothing major. Looks real nice.
As it turns out, the small hole under the wastegate valve joins up and empties into the valve stem guide. It is a split design. Wierd. I will try and take photo's of everything tonight.