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Engine Specific Info and Questions => IDI Engine => Topic started by: Gizmoman on March 15, 2017, 11:43:00 pm
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Hey all, been a while since I've been here. Good to see the board's still running strong
Ok, I have an 82 Vanagon with a 1.9 AAZ, Holset turbo and WAIC. The engine runs fantastic thanks to much of the help I received here over several years during the rebuilding process, and the wife and I have enjoyed several long camping trips without a single issue. The transmission was worn then and now it's time to move up to a 5 speed which I recently purchased used.
I have sent an AAP 5 speed off for rebuild and have instructed Bill at AZ transaxle to change 5th gear to 0.77 from the stock 0.82.
I am running a 26.7 diameter tire and my excel spreadsheet shows I will be at 70 MPG @ 3100 RPM.
With my current DX transmission with an 0.86 final ratio, EGT's can exceed 1100 F (my warning setpoint) if I am going up a moderately steep grade of around 3-4% and trying to maintain 70 MPH. The Holset turbo is running around 12-14 psi at that point and while it can easily hit 20 psi if I floor it, I can't because I'm already hitting my EGT warning. It just feels like the relationship between how much it fuels and how much boost I have is off a bit. Giles had set the pump based on a K-14 which is what I had at the time.
I believe this relationship can be adjusted using the star wheel in the IP but I'm not sure which way I would turn the wheel or if there are other adjustments that would provide more boost and less fuel. I have turned in the fuel screw
In short, do you think the 0.77 is a bit much of a ratio change as I will hit high EGT's sooner as it is now, or is there a possibility my IP is simply adding too much fuel and not enough boost and if I can get it set properly, the 0.77 will be fine.
Any info someone could provide would be very helpful. The transmission ratio change is expensive and if it causes me to downshift sooner than I do now, it would be quite disappointing.
If the star wheel adjustment is the ticket, can someone tell me which way to turn it (CW or CCW) looking into the top of the LDA.
Thanks all
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You would loosen the screw (counter clockwise) to lessen fuel. Does it smoke at all as is? I would expect your egt to be lower with the awic. Maybe you should try adding a bit of boost? I was under the impression the holsets were factory set closer to 30psi. What is your timing set at? 1100f is still fairly reasonable. I usually let off around 1250 and occasionally push it over 1400f for a split second.
My Pump was built for closer to 26psi If I remember right and at stock boost levels on my k24 once the lda opened I would make a smoke screen and egt would go through the roof. Disconnecting the line to the lda made the issue go away and I could pull faster up hills without hitting a temperature wall. I'm not saying thats your issue, but I'm kind of thinking the lda is cut too agressively or the springs are a bit weaker then they could be. A stiffer spring would bring the fuel on after more boost is built and in turn have less of an effect on cylinder temps. Or a 1.6td boost pin might workout better if you dont want to play with the boost.
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LDA adjustments don't really come in to play for steady state cruising - it only delays full fueling when the pump is operating close to full power. There's nothing you can adjust on the pump that will change the amount of boost you have at cruise. The LDA is a pollution control device which deals with changes in engine load more than anything.
Boost pressure is a function of turbo geometry and exhaust flow. If the wastegate isn't open yet (which it shouldn't be given the boost settings you are describing) then the only way to get more boost with a fixed geometry turbo is to add more fuel, which increases the exhaust pressure.
1100F is a pretty low EGT to be limiting yourself to. The engine and turbo can handle more than that safely. 1400F would be a safe place to set your EGT alarm.
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LDA adjustments don't really come in to play for steady state cruising - it only delays full fueling when the pump is operating close to full power. There's nothing you can adjust on the pump that will change the amount of boost you have at cruise. The LDA is a pollution control device which deals with changes in engine load more than anything.
Boost pressure is a function of turbo geometry and exhaust flow. If the wastegate isn't open yet (which it shouldn't be given the boost settings you are describing) then the only way to get more boost with a fixed geometry turbo is to add more fuel, which increases the exhaust pressure. Apparently I just don't understand how it works at all but do find it hard to believe I cant change the fuel to boost ratio.
Thanks all for the replies. The reason for the 1100F setting is to warn of over-temp approaching. I do take it to 1400F for short stints.
My old head had broken heat shields and from what I've read, this is quite common. It may be "common" because everyone thinks 1400 is OK
It's not so much needing boost at cruise
1100F is a pretty low EGT to be limiting yourself to. The engine and turbo can handle more than that safely. 1400F would be a safe place to set your EGT alarm.
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Its not so much needing more boost at cruise, I'd like to have more boost when under load like climbing a 3% grade, common on West coast freeways. I have wired the wastegate shut and I suppose I could hit 30 lbs if I kept my foot into it. The boost I have at cruise is around 6-8 psi at 70 MPH. Remember, this is a breadbox in the wind.
I've tried just stabbing the pedal to the floor when climbing these grades but EGT's can go well over 1400 very quickly.
Thanks all for the replies.
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I know boost is relative to load and the amount of fuel going in. I'm thinking the wind resistance and weight of the van is enough to load the engine enough to engage the lda, but because he is just cruising the boost isnt raising enough to properly burn the fuel for the amount of load. I think the lda is just too aggressive. In a lighter car with better aerodynamics this issue probably wouldn't exist. I'm experiencing the same thing in my samurai, admittedly my turbo wasn't set to make enough boost to burn the fuel but it was too much fuel regardless. Turning the fuel screw out made it that if I didn't raise the rpms enough before dropping the clutch the engine would lag and just crawl until it got to 1500 or so then start to accelerate, and still have unsafe egt temps at high rpm and high load. It was either too much fuel at boost, or not enough when off boost. Disabling the lda and increasing fueling gave significantly better exhaust temps (like 1200f max), and although it didn't accelerate as fast, the top speed and hill climbing speeds were increased because I could actually push the pedal enough up long hills to maintain speed without my egt going through the roof.
I would suggest just trying to disable the lda. Pinching the vacuum line doesn't cost you anything and it will quickly tell you if the on boost fueling is your issue. If it is, I would suggest getting a less aggressive boost pin, like one from a 1.6td that is adjustable. That way you can de-tune your higher end fueling without disrupting your preboost acceleration.
In my opinion the LDA needs to be cut in a way that off boost you have maximum fueling for the amount of air, and then at full boost you have maxium fueling for that much air. The slope on the lda would ideally be the same shape as the efficiency map of the turbo with a spring that allows them to raise at the same speed. This would ensure optimal fueling for the entire torque curve and wouldnt allow the egt to get out of control assuming the intake temperature is within reason.
A stiffer spring on his lda would allow him to have the same fuel potential but it wouldn't kick in until more boost has been made and could potentially be burned efficiently at lower temps would it not?
I just read the 1.6td lda spring is stiffer then the aaz one. Maybe it would work better for you?
http://vwdiesel.net/forum/index.php/topic,32848.0.html
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The LDA isn't going to change anything. Disabling it will reduce the power available with the pedal to the floor, but it's won't change anything at part load.
This is a diesel, not a gasser. It always takes a full cylinder of air, then varies fuel to control acceleration. Unlike a gasser there's no management of the fuel:air ratio. If the LDA were "enriching" things the engine would just go faster, exactly the same as if you pushed the pedal down further. The LDA is literally a movable stop for the "pedal to the floor" fuel delivery inside the pump. The governor lever only ever touches it when the operator is asking for maximum fueling - any time you are not requesting the maximum fuel delivery the pump can achieve the LDA doesn't come in to play. It's only job is to prevent the pump delivering 100% of its configured maximum fuel until there is boost present purely to control smoke.
If you believe your EGTs are too high at anything less than "pedal to the floor" and you have a fixed geometry turbo with a closed wastegate your only choices are to change to a turbo that is more suited to your needs (one which produces more boost in the conditions you are experiencing) or find a way to reduce the intake air temperature. Every 1 degree reduction in IAT generally results in a 3 degree reduction in EGT.
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... Turning the fuel screw out made it that if I didn't raise the rpms enough before dropping the clutch the engine would lag and just crawl until it got to 1500 or so then start to accelerate, and still have unsafe egt temps at high rpm and high load. It was either too much fuel at boost, or not enough when off boost. Disabling the lda and increasing fueling gave significantly better exhaust temps (like 1200f max), and although it didn't accelerate as fast, the top speed and hill climbing speeds were increased because I could actually push the pedal enough up long hills to maintain speed without my egt going through the roof.
. . .I just read the 1.6td lda spring is stiffer then the aaz one. Maybe it would work better for you?
http://vwdiesel.net/forum/index.php/topic,32848.0.html
I backed off the fuel screw yesterday about 1/2 turn in. The result was identical to your description. My EGT's don't climb as fast but there's some serious clutch slipping required to get it going - especially if I'm starting from a dead stop on an incline, I can imagine this thing would be undrivable in San Francisco :)
Egt's are lower though once I'm up to speed and they don't come up as quickly going up those 3% grades. I think I'll turn out the screw 1/4 turn and see if the compromise is livable.
As for cooling the intake, I have a probe in it and with my water to air cooler set-up, it seldom goes over 30 degrees ambient.
I need to go back and read up some more on the star-wheel and the spring stiffness as well. Not to doubt those that are more familiar with these pumps/engines and turbos but I just need to get my head around it.
As usual, Andrew Libby once told me that I needed to have a variable turbo to achieve my goals and that the Holset would not be ideal.
I believe he was correct.
I still have to check out the star wheel and or spring stiffness cause I'm obviously hard headed.
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The other option that I didn't see mentioned was pump timing. Try bumping your timing 3mm advanced and then 6 degrees (from the advanced setting) retarded and see how that effects everything.
Do you have any boost leaks? Are there any restrictions in your exhaust setup?
With regards to the spring for the LDA, increasing the spring tension will delay at what boost psi the pump starts to add more fuel. I don't know how a Holset spools but I know how a K14 does and I think that's where your issue lies.
Based on what you said about winding the max fuel screw out 1/2 a turn and finding your EGTs to have been improved, I would put it back to where it was and significantly increase the tension on the spring in the LDA.
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Advancing the timing a little may indeed help with this situation - advancing the timing reduces EGTs, but it also will cause the turbo to be a little less responsive. Back to that whole "exhaust pressure builds boost" thing...
The comments about needing a variable geometry turbo to achieve your goals is pretty much my point.
You want to push something up a hill, it takes a certain amount of energy from burning fuel to do that. The fuel required to push the vehicle at a particular speed up a particular grade, assuming complete combustion, is essentially a constant. More fuel, more speed. Less fuel, less speed.
To not melt your engine you need enough cool air entering the engine. More air mass, lower exhaust temperature. Less air mass, higher exhaust temperature.
Since you need a certain amount of fuel to do the work required altering pump settings can't really do anything for you, with the exception of timing. Timing adjustments will shift things around a little - advance will reduce EGTs but increase peak cylinder pressure. Retarding the timing does the opposite.
If you saw an EGT reduction after backing out the fuel screw you probably found you needed to press the pedal down more. These pumps have a load dependant timing feature that adds a few degrees of advance when the accelerator pedal is at around 3/4. More than likely that's what you're seeing.
In short, if you can't get your intake temperatures any lower and you can't add any more air the only thing you can do is add a little advance, but too much and you'll blow your head gasket due to increased cylinder pressure. There's not really much room for adjustment...
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Update - I spent the morning turning the starwheel and going for short test runs. I also put the fuel screw back as it was too lean to live with. Actually, I may have put the fuel screw to a tad richer than it was because, the star wheel adjustments seemed to be helping quite a bit. Changing the fuel screw past where I have it now makes the idle adjustment do nothing so I have backed it off a bit.
I have raised the starwheel (added spring tension) by 22 clicks. The thread is so fine that's really not much. I've read where guys say they moved it three clicks and had good results - I find that tough to believe. Possibly they meant 3 complete turns.
My last adjustment was to spin the diaphragm pin 189 degrees so it wasn't so aggressive. This seemed to help a bit more but I think the star wheel needs to go possibly another 12 clicks and the pin needs to go back where it was riding in the groove.
Burn your money - Interesting you should mention boost leaks. I know all my piping and hose connections are rock solid but possibly it's leaking at the intake manifold to head, exhaust to turbo connection or the waste gate is somehow leaking. As I mentioned, I currently have the waste gate held shut with bailing wire and hitting 20 psi should be easier than it is:o.
On one of my test runs I saw the boost hit 20 then drop off rapidly to 3 or 4, It's been OK since but I haven't tried a hard run again.
One thing I can say is these small adjustments have changed the characteristics of the motor dramatically improving the low end torque and reducing the EGT's a bit as well. I also notice the EGTs seem to drop a lot faster when I back off - not sure why but I'm not complaining.
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Advancing the timing a little may indeed help with this situation - advancing the timing reduces EGTs, but it also will cause the turbo to be a little less responsive. Back to that whole "exhaust pressure builds boost" thing...
The comments about needing a variable geometry turbo to achieve your goals is pretty much my point.
You want to push something up a hill, it takes a certain amount of energy from burning fuel to do that. The fuel required to push the vehicle at a particular speed up a particular grade, assuming complete combustion, is essentially a constant. More fuel, more speed. Less fuel, less speed.
To not melt your engine you need enough cool air entering the engine. More air mass, lower exhaust temperature. Less air mass, higher exhaust temperature.
Since you need a certain amount of fuel to do the work required altering pump settings can't really do anything for you, with the exception of timing. Timing adjustments will shift things around a little - advance will reduce EGTs but increase peak cylinder pressure. Retarding the timing does the opposite.
If you saw an EGT reduction after backing out the fuel screw you probably found you needed to press the pedal down more. These pumps have a load dependant timing feature that adds a few degrees of advance when the accelerator pedal is at around 3/4. More than likely that's what you're seeing.
In short, if you can't get your intake temperatures any lower and you can't add any more air the only thing you can do is add a little advance, but too much and you'll blow your head gasket due to increased cylinder pressure. There's not really much room for adjustment...
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Clear, concise and to the point ^^^
I'm going to move the star wheel up some more to stiffen the spring as it does seem to be helping and it's easy to do. I should mention that this pump is from a 1.6 and may already have the stiffer spring (it's blue if that means anything). Giles set the pump for a K14 and a max boost pressure of 14 psi. Ironically, 14 psi is about where it gets to when the EGT's start a rapid increase. That said, a variable turbo may be the ideal solution and I'll be on the hunt for something "affordable" to replace the Holset :(
I did speak to Giles about adjustments I could make for the Holset and he said I'd need to send the pump back to him and he would see what he could do. I don't blame him for that response at all but it's an expensive option that may or may not work as he has no experience with a Holset which he readily admitted.
I'll report back after I make the adjustments. I'm also going to check for boost leaks as there are times when the boost readings act real jumpy - possibly it's my digital gauge but I need to look for possible leaks. I believe the best way to do that nay be to make a fitting and introduce 20 psi where the turbo discharge connects.
(https://s25.postimg.org/s2p3w3eez/DSC01044.jpg) (https://postimg.org/image/s2p3w3eez/)
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Suppose the one other thing to check would be the exhaust side... Was it you or someone else that discovered they had a massive exhaust restriction? The other factor in building boost is of course post-turbo restriction.
The boost gauge fluctuations could definitely be pointing to a problem. You should see a corresponding increase in smoke, a drop in engine performance and a temporary rapid increase in EGTs if the boost leak is real - if the engine performance doesn't change at all then I'd be chasing down a gauge problem.
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It's embarrassing to admit that when I wired the waste gate closed, I was in a campground and didn't do a proper job. The bail wire was wrapped around an object that could flex :o. This morning I have redone that mess and now the gate is definitely closed. While I was under there, I inspected everything else and there is no sign of any leaks either on the intake, or exhaust side.
vanbcguy, you've a good memory - yes, I had a huge restriction with the muffler the PO had installed but remedied that quite a while ago. Everything is 2-1/2" now.
I have turned the star wheel way up (quit counting clicks) and backed off the fuel screw 1/8 turn. It took 6 test runs this morning to get to this point but the outcome is acceptable now.
I can hit 21 PSI if I floor it and am now getting to 15 before the egt's go over 1200F. I also have much more low end grunt and the changes have greatly shortened the flat spot I had before boost would kick in.
A variable turbo would be ideal but this will do for now.
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Ha - yeah that's definitely not ideal. Hopefully you'll be able to work with what you have now that you're getting the most out of it!
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On my holset setup I cannot throw enough fuel to it. The more aggressive you get with it the more boost it makes and in turn I will actually see the egt raise to almost 800f and then come down. I have mine turned all the way up and the pump timing set .94 and I cannot get past 800f. If I baby it the egt stay around 750f...what kind of RPM are you running to get the egt? Do you have a manual boost controller?
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Good to hear you have it at a more acceptable level now. I'm also interested to hear what you have your timing set at.
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On my holset setup I cannot throw enough fuel to it. The more aggressive you get with it the more boost it makes and in turn I will actually see the egt raise to almost 800f and then come down. I have mine turned all the way up and the pump timing set .94 and I cannot get past 800f. If I baby it the egt stay around 750f...what kind of RPM are you running to get the egt? Do you have a manual boost controller?
I'm not sure of the exact RPM as I'm watching the EGT numbers. My guess is 35-3800.
I have no boost controller because the wastegate is physically wired shut. I did that because I couldn't get over 16 and was loosing my patience. The most I have ever seen is 21 lbs but again, Giles tuned the pump for a K14 at 14 psi max (as I instructed him to do). Also, the pump is from a 1.6. Not sure why the PO did that but that's what was on it when I bought it. Giles said the 1.6 pump would work fine for my needs but again, that was before I went to the Holset.
Theman, I know you built a very nice intake. Do you think the one I built above may be restricting the air?
I don't remember where my timing was but I bought one of those tools that uses a pulse signal (suggested by Andrew Libby) and hooked up a timing light. All I can remember it was at the recommended setting - again by libby.
It starts instantly after the glow plug light goes out if that tells you anything.
I could look back at those post several years ago and see if I can find the conversation.
EDIT - I did a search and found that my final setting for the timing was .95mm.
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0,95mm sounds good. If you feel like chasing low probability possibilities, check for air in the feed line while the EGTs are maxing out. Air in the fuel may be causing the dynamic timing to cut back some.
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0,95mm sounds good. If you feel like chasing low probability possibilities, check for air in the feed line while the EGTs are maxing out. Air in the fuel may be causing the dynamic timing to cut back some.
Interesting. Not sure how I'd check that but I do have an inline pump that I could turn on and see if it changes anything.
I may tale it to work tomorrow just to take it for a good run. Ill report in when I get home.
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The drive to work was much better than usual as I have several 3% grades. One is on the freeway typically at 70 MPH(3400 RPM). The other is on the way home and is a 3rd gear pull as its a residential street. Boost is coming on sooner and 1200 F is hard to reach (used to be easy). Had I not backed out the fuel screw, I doubt I'd ever make it to 1200 but I added a bit of fuel during my adjustments as a compromise because it has always been sluggish at the bottom end. Now I have good bottom end, lower egt's and higher boost. I still don't understand why I cant reach 30 PSI like theman with his Holset but it's probably because I don't get the fuel/boost concept entirely :)
Looking forward to the rebuilt 5 speed with the closer gears and feel better now about raising the final from 0.86 to 0.78.
Thanks for everyone's help - this is still my favorite forum.
Jim
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On my holset setup I cannot throw enough fuel to it. The more aggressive you get with it the more boost it makes and in turn I will actually see the egt raise to almost 800f and then come down. I have mine turned all the way up and the pump timing set .94 and I cannot get past 800f. If I baby it the egt stay around 750f...what kind of RPM are you running to get the egt? Do you have a manual boost controller?
I'm not sure of the exact RPM as I'm watching the EGT numbers. My guess is 35-3800.
I have no boost controller because the wastegate is physically wired shut. I did that because I couldn't get over 16 and was loosing my patience. The most I have ever seen is 21 lbs but again, Giles tuned the pump for a K14 at 14 psi max (as I instructed him to do). Also, the pump is from a 1.6. Not sure why the PO did that but that's what was on it when I bought it. Giles said the 1.6 pump would work fine for my needs but again, that was before I went to the Holset.
Theman, I know you built a very nice intake. Do you think the one I built above may be restricting the air?
I don't remember where my timing was but I bought one of those tools that uses a pulse signal (suggested by Andrew Libby) and hooked up a timing light. All I can remember it was at the recommended setting - again by libby.
It starts instantly after the glow plug light goes out if that tells you anything.
I could look back at those post several years ago and see if I can find the conversation.
EDIT - I did a search and found that my final setting for the timing was .95mm.
I remember your intake a little, it could be restrictive. Do you have a stock intake that could be easily swapped to see if there is any change? Or take yours off and have it flow tested?
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I remember your intake a little, it could be restrictive. Do you have a stock intake that could be easily swapped to see if there is any change? Or take yours off and have it flow tested?
I don't have another intake and if I did, it would be tough to plumb my turbo to it at this point.
Here's another shot of it. . .
(https://s25.postimg.org/wv83z0nun/DSC01046.jpg)
I think I have it modeled in Solidworks and could probably do a flow test on that. Do you know what flow numbers I would use? The software will only test one input and one output at a time but then, that's the way it works anyhow :).
I still need to do a pressure test of my boost system. I have made a plug to insert into the intake and will put 20 PSI to it and check for leaks this weekend. I was running hard next to a concrete barrier the other day with the window rolled down and I swear I could hear a hissing noise while I was boosting in the high teens.
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i think there must be a boost leak, you have a larger engine and smaller turbo than theman53.
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Nice to see you on here Jim and also good to hear the van has been running well. I think the AAP will be a nice upgrade. I also think the .77 5th will be a good choice considering the rest of your setup.
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i think there must be a boost leak, you have a larger engine and smaller turbo than theman53.
Yup - boost leak.
I made a fitting and plumbed a regulator set to 30 psi and installed it into the intake before the WAIC.
Sure enough, I had two leaks, one at the turbo outlet, and another at a 30 degree fitting. They were small but noticeable after I sprayed some Mr Bubble mix on em.
I took it all apart and inspected the silicone fittings - no cracks. However I don't think I had the clamps properly set over the bumps on the turbo or the elbow. I re-fitted everything and checked it again.They are fixed now and I took it for a run on the freeway. Egt's seem to be running about 200F lower than they were which is fantastic but I can still get to 1200F if I tromp on the pedal and hold it for a bit (which I expected).
What gets me is I can only hit 20 psi max. As soon is it gets to 20 it drops off to 11 or 12 (like hitting a light switch) and feels like its running out of fuel. If I back off the stumble quits.
It doesn't get to 20 and sit there - it immediately drops to 11 psi. Keep in mind, I have the waste gate wired shut.
I suppose if Giles built it for a K-14 possibly it can't fuel enough to make the Holset boost over 20. Now that the leaks are fixed though, I am hitting higher numbers easier and quicker than I was.
I'm still perplexed what the stumbling is and I don't know enough about the pump to know if there's anything that can be done. Maybe its something as simple as a cruddy pick-up screen in the tank. This thing is 35 years old and I have no idea what the inside of the tank looks like.
I should mention that my fuel lines are clear and I see no bubbles (at idle anyway). Also, I have a 12 volt diesel pump inline which I can turn on and off from the dash. I made several test runs with the pump on and pump off - no difference.
Nice to see you on here Jim and also good to hear the van has been running well. I think the AAP will be a nice upgrade. I also think the .77 5th will be a good choice considering the rest of your setup.
Good to hear from you as well libby!
Any suggestions from the group as to what could cause this stumble at 20 PSI would be appreciated.
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I'm not sure. Does it happen regardless of rpm? In other words, if you are cruising along at the top of 3rd gear do you get the stumble at 20psi the same as if you are accelerating from the bottom of third? What is the history of your valve springs? Maybe something like high exhaust pressure is pushing open the exhaust valves and giving a nice dose of EGR?
One option is to consider a well-fueled 18 psi decent abuse on a vanagon trans and solve the 20 psi stumble by limiting boost to be below that.
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I'm not sure. Does it happen regardless of rpm? In other words, if you are cruising along at the top of 3rd gear do you get the stumble at 20psi the same as if you are accelerating from the bottom of third? What is the history of your valve springs? Maybe something like high exhaust pressure is pushing open the exhaust valves and giving a nice dose of EGR?
One option is to consider a well-fueled 18 psi decent abuse on a vanagon trans and solve the 20 psi stumble by limiting boost to be below that.
Point well taken. The tranny I have has served me well and I hate to thrash machinery. However, I need to see what this thing can do and I'd rather do it with this one than the new rebuild. I very seldom put the pedal to the floor and don't intend to do so with the new transmission. However, ever since the rebuild of the motor, I've had this feeling that I'm missing something. It just feels like its struggling more than it should - hard to describe.
20 Psi is a rare beast and only shows up for a split second when I'm really into it so, no, it only happens when I hit between 18-20 psi.
I have a "tiny tach"which works well but not too good for a quick glance I'm guessing RPMs are probably in the 35-3800 range at that point. It then stumbles immediately dropping to 11 PSI - I back off, and all is well again. This morning on the way to work it did do something it has never done - it felt like the turbo had just quit or I was running out of fuel. I was doing about 55 or 60 and when I gave it even a small amount of fuel, it just went flat - did this several times at ever bump of the pedal. I immediately headed for the nearest exit and when I got off, it was fine. It took a few blocks to find my way back to the freeway and it never happened again. It is still doing the 20 psi stumble and it must have something to do with the major increase in tension of the star-wheel spring as that's about all I've changed (last weekend).
Maybe now that my boost leaks are fixed, I should back the spring off?
7 psi is cruising at 60-65 so it's not that big of a deal. I'm just trying to find the limits and they seem to be much closer than I think they should be. That said, Theman's 1.6 has some serious porting and other mods and his car probably weighs half as much as my van. It's certainly more aerodynamic ;). Pitting his 30 psi and 800F Egt's against my brick is not a good measure.
Oh, as to the valve springs, the head is was a brand new Kolbenschmidt, I believe there's not much chance of an issue but I spoze anything is possible.
As I'm writing this, I recall that the Tiny Tach may record the highest RPM, I'll do some checking and see if I can get it to reveal itself. Possibly I'm floating the valves without realizing it.
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When it's stumbling, what happens if you just hold your foot to the floor? Does it resolve or does it just stay in "limp mode". What happens to your EGTs?
Another left field thought, are all 4 mounting bolts for the pump secure?
Lowering the spring tension in the LDA may help your problem, or turning up the max fuel screw.
PM sent
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When it's stumbling, what happens if you just hold your foot to the floor? Does it resolve or does it just stay in "limp mode". What happens to your EGTs?
Another left field thought, are all 4 mounting bolts for the pump secure?
Lowering the spring tension in the LDA may help your problem, or turning up the max fuel screw.
PM sent
When it stumbles, I back off immediately and I've quit trying to hit 20 psi till I figure out what's going on as it sorta freaks me out.
All four screws are in excellent shape and as reasonably tight as I can get them with a big screwdriver.
I have the spring pretty tight at this point and may back it off in the morning. I think I'm making too many adjustments at the same time and need to be more methodical about this as I move forward. The one good thing that has come of this so far was the suggestion to look for boost leaks. I found two small ones and now they are fixed lowering my EGT's about 200F across the board.
I should add that during my 30 PSI test into the intake (after I fixed the two bubbling leaks), I could still hear air. As I did some extensive welding on the intake, I may have a leak at one of the ports but it's too hard to reach and check. I'm sure I checked the surface for flatness before I installed it though. Possibly I needed to roll the engine to TDC to keep from blowing past the valves as that's probably all I am hearing now.
Open to any and all suggestions and appreciate the feedback. I'm not one to give up, just don't know what direction to take at this point.
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All four screws are in excellent shape and as reasonably tight as I can get them with a big screwdriver.
I mean the ones you would loosen to adjust the timing.
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All four screws are in excellent shape and as reasonably tight as I can get them with a big screwdriver.
I mean the ones you would loosen to adjust the timing.
You did say bolt ::) - I'm going to do some more methodical tweaking to the pump this morning, backing off the LDA spring, checking out the pin position and grind, etc. I may check for boost leaks again with the engine at TDC. If I can still hear an air leak at 30 psi, there's a boost leak at the manifold, or trouble in the valvetrain. It also wouldn't hurt to check timing again - and the pump mounting bolts ;)
The 20 psi stumble is instantaneous though and whatever is causing this is something abrupt - none of the above would give an on/off change (to my knowledge). burn_your_money, earlier you asked if I kept my foot in it during the stumble and I said no. I should clarify that I let off because it was obvious that adding fuel with my foot made the engine act like it was running out of fuel. It felt exactly like a gasser with a bad fuel pump (which I gave felt before).
Not to muddy the water but I should mention that I have never seen smoke from this engine - regardless of any of my adjustments. Is there a "standard" for the number of turns the fuel screw should be set to?
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If the boost pin is conical, I would fairly strongly recommend against grinding it. If it is the AAZ 'joke pin' then grind away.
When you are checking for a boost leak are all intake valves closed? You should check for any leaks on the exhaust side as well.
You might consider making a couple runs with the feed and return running to a different fuel container just to eliminate the fuel tank, lift pump, etc, from the mix.
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Thanks for the info libby - excellent as always.
Right now I'm trying to stay focused on the simple fact that this engine (since the complete rebuild if it and the IP) has alway hit high EGTs at around 14 psi.
Sure, I can get it to change a tad by tweaking things a bit but nothing I have done has helped significantly. Even changng from the K14 to the Holset and adding a water to air intercooler didn't do as much as I think it should.
Today I found this link and read it entirely https://www.pug306.net/index.php?pageid=boschtuning (https://www.pug306.net/index.php?pageid=boschtuning)
Based on that read, the LDA's job is to provide the proper boost to fuel ratio and frankly, the changes I have made to the spring tension or fuel screw has had little effect. I even spun the boost pin 180 degrees and felt no change whatsoever.
I removed the boost pin again this morning (it slides out very easily by the way - no turning required) and looked down into the pin bore and can see no pin sticking out at all. I then made a "feeler" using a thin piece of wire with a short 90 degree bend at the tip. Feeling down the bore, the wire actually goes into a small perpendicular hole about 1/8" deep when I get it close to the bottom of the bore.
I know Giles has an excellent reputation but he's human. Is there a chance he left the pin out or forgot to put it in for some reason?
Or maybe the pin doesn't stick out until I begin fueling.
Here are some photos of where I am right now. . .
(https://s25.postimg.org/fx9jwjvej/BOOST_PIN_BACK.jpg) (https://postimg.org/image/fx9jwjvej/) (https://s25.postimg.org/6e4ggtxa3/BOOST_PIN_FRONT.jpg) (https://postimg.org/image/6e4ggtxa3/) (https://s25.postimg.org/xd8bbzjqz/BOOST_PIN_REMOVE.jpg) (https://postimg.org/image/xd8bbzjqz/) (https://s25.postimg.org/gdzcwq8jf/BOOST_PIN_SIDE.jpg) (https://postimg.org/image/gdzcwq8jf/)
(https://s25.postimg.org/52wp8d1ob/IP_VIEW_1.jpg) (https://postimg.org/image/52wp8d1ob/) (https://s25.postimg.org/a2u5gb7az/IP_VIEW_2.jpg) (https://postimg.org/image/a2u5gb7az/) (https://s25.postimg.org/mvi9g8iwr/LDA_OPEN_1.jpg) (https://postimg.org/image/mvi9g8iwr/) (https://s25.postimg.org/4h7qc96m3/LDA_SPRING_HEIGHT.jpg) (https://postimg.org/image/4h7qc96m3/)
(https://s25.postimg.org/k3yzpmke3/LDA_SPRING_WIRE_DIAMETER.jpg) (https://postimg.org/image/k3yzpmke3/) (https://s25.postimg.org/qvpesh9dn/STARWHEEL_HEIGHT_1_X.jpg) (https://postimg.org/image/qvpesh9dn/) (https://s25.postimg.org/72dazrvzv/PIN_NUMBER_34.jpg) (https://postimg.org/image/72dazrvzv/) (https://s25.postimg.org/5oq9i7m4b/PIN_RUB_DETAIL.jpg) (https://postimg.org/image/5oq9i7m4b/)
I am open to all thoughts.
EDIT:
I looked inside the boost pin bore while I moved the fuel lever to full throttle. It does make a small pin stick out a bit so it is there.
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That is not the intake I was thinking of, you should be just fine with that design.
See if you can move the go pedal cable and get the pin to pop out. It looks like a pin was riding on that ramp at some point, so it should be there somewhere.
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That is not the intake I was thinking of, you should be just fine with that design.
See if you can move the go pedal cable and get the pin to pop out. It looks like a pin was riding on that ramp at some point, so it should be there somewhere.
I did and the pin is there - I edited the previous post to reflect that.
Thanks for the confidence in the intake build - means a lot coming from you.
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I should point out that in the article I linked to a few post back, there is a limit to how much fuel the pump can put out by grinding the pin - mine has obviously been ground. It also states that there are some internal mods that can be done to increase stroke but a pump dyno would be required (plus some good knowledge).
As I mentioned previously, when I sent the pump to Giles several years ago, I told him I was running a K14. A K14 can boos most efficiently to 14 psi before it begins to flatten out (as I understand it).
That said, I believe I may be at the pump max for fueling without Giles or a good rebuilder making more internal changes. If that's the case, without more fuel. I don't see how I can expect more boost. Not that I want to run more than 20 but with the wastegate wired shut, I should be able to exceed 20 with this turbo - unless there's not enough fuel.
Still doesn't explain the 20 PSI stutter.
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A stumble like you are describing can really only be a lack of power to the shutoff solenoid or a lack of fuel to the pump.
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A stumble like you are describing can really only be a lack of power to the shutoff solenoid or a lack of fuel to the pump.
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It seems to be directly related to 20 lbs of boost so the solenoid is out. I have no idea what other thing couls cause such an abrupt loss of fuel - if that's even what it is.
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Here's some more info if anyone can use it.
- From the top of the boost pin center stem to the hub edge of the starwheel is currently 0.124"
- when the spring is fully compressed, it is .380" tall
- I measured the depth from the spring seat in the cap to the edge of the cap and got 0.462. Then I measured from the top of the spring (in it's free state) down to the top edge where the cap sits. This came out to 0.301".
This means the current star wheel setting has the spring compressed 0.161". which is far from fully compressed.
The free height is 0.927, compressed height (cap on, current starwheel position), the spring is compressed to 0.766.
So, the pin can travel approximately 0.386" until the spring is fully compressed (assuming the screw on the cap is backed all the way out).
Pin ramp dimensions:
The pin's distance from the top edge of the round section at the end, to the end of the ground ramp is about 0.52" and I can see where the pin has made a small line up the pin. The pin-line starts just above the top edge of the round.
Also, the ground ramp begins about 0.16" above the round section and it appears that the pin has been going from the original ramped surface and onto the new ground surface during its travel. It leaves the original surface at about 1/6th of it's travel.
I chucked the pin in the lathe and followed the track made by the pin using a similar diameter probe.
The linear travel of the pin shows it has been moving around 0.280". The ramp nets the total movement of the pin to be 0.140" over that travel distance.
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OK,
Here I am replying to my own post again but possibly this thread may help someone else.
After studying the grind on the boost pin (probably ground for K14 turbo), I decided I still didn't have enough spring pre-load. So I turned the starwheel even higher (more spring pressure) and it seems to have put things into a better place. The height from the starwheel hub to the top of the pin bore is now only 0.95" [2.41 mm].
A test drive shows I can boost to 20 psi if I floor it and in about 3-5 seconds, the egt's reach 1350F - not nearly as quickly as they did before. Also the stumble and instant boost drop from 20 to 11 psi is gone entirely and I may never know what it was.
All in all, I have learned a lot, especially today.
I believe I could grind my own boost pin to more closely match what I want the fuel to boost ratio to be and back the starwheel off considerably. This would provide a much smoother transition of power than I have now which is fairly abrupt. This hard hit is not being very nice to my drive train, I'm sure.
The pin has a #34 stamped on the end. does anyone know a good source to purchase a new one? I should get several if they aren't too expensive. It may take several different grinds to get it right.
Thanks all.
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Try running a new temporary return line from the pump to the drivers seat and back. Keep an eye on the line after some hard pulls to see if you are getting any air in the line. It may take up to 30 seconds for the air to make it to the drivers seat depending on how long the hose is.
What happens after 1350F? Does it stop climbing or do you back off?
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Try running a new temporary return line from the pump to the drivers seat and back. Keep an eye on the line after some hard pulls to see if you are getting any air in the line. It may take up to 30 seconds for the air to make it to the drivers seat depending on how long the hose is.
What happens after 1350F? Does it stop climbing or do you back off?
That would take a lot of hose for sure.
As for the 1300, I back off. I have melted the #4 piston on this engine before and and have become obsessive with high EGT numbers.
I spent five years and untold bucks on this one and 1350F is my ceiling. The warning light comes on at 1100 ; )
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Since it's just a temporary thing you could use cheap PVC or whatever hose. It just has to be clear enough to see bubbles.
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Since it's just a temporary thing you could use cheap PVC or whatever hose. It just has to be clear enough to see bubbles.
Possible air in the line has been mentioned several times, so doing somthing to identify/stop it makes sense. I probably have enough of the clear hose in a box somewhere. Maybe I could get the wife to watch it while I drive to make sure I don't miss any bubbles. She likes being involved in these projects and this one has kept me busy for sure.
I must say though that since my last increase of LDA spring tension, the stumble is gone. I can also reach 20 psi with egts eventually reaching 1300F. As I won't be pushing it this hard very often, I may just hold off on this project until I can grind a 1.9 boost pin that is a better match for the Holset.
Does anyone know where I can get 1.9 pins?
I have found them on ebay but only in Europe.
Thanks,
Jim
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This morning I ran the star wheel all the way to the bottom of the stem - didn't count the turns but I think it was less than 10.
Took it for a spin but was again getting high EGTs and it wouldn't boost over 10 psi.
Back at the shop, I started thinking about using a spring with a higher compression rate and went to my collection of springs. I actually found one with nearly the same ID and a tiny bit larger wire diameter. It was also about 3/4" taller than the stock spring.
I installed the taller spring onto the lowered starwheel, put the cap back and went back out. I boost was now going to 16 max and the flat spot seemed to reappear. I went back, heated the spring under load and shortened it by about 1/2". I dropped it in oil while it was still hot to keep the temper.
The new shortened spring is in now and back to hitting 20 psi without too much effort. Also, The only way I can get it to hit 1300 is to really hold it for 30 seconds or so at 20 lbs. The good news is I can maintain 18 lbs for quite a while and the egts stop climbing at 1250F.
This is about as close to my goals as I could hope for and am going to consider this a successful ending.
Thanks for everyone's valuable assistance. I'm still interested in grinding a 1.9 boost pin if I can find one and would appreciate a link or a source.
Jim
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The 1.9 is running netter than it ever has. Still, I bought two of these and will mess around with some additional grinding.
http://www.ebay.com/itm/321182846275?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT (http://www.ebay.com/itm/321182846275?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT)
I'n not entirely positive they will fit my 1.6 pump but they weren't too expensive.
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Those should fit.
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Aren't you a machinist? You could just make a cylinder and then drill and tap the top of it for a bolt rather than what Bosch did with the stud. You could even make it from aluminum until you find the profile you like then make a steel one.
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Aren't you a machinist? You could just make a cylinder and then drill and tap the top of it for a bolt rather than what Bosch did with the stud. You could even make it from aluminum until you find the profile you like then make a steel one.
I thought of that, figured I'd start with a "known" value. Who knows, it might be just right although it looks to steep at the beginning.
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I believe the pin should only ride on the single long taper, not on the steeper angle at the bottom.
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I believe the pin should only ride on the single long taper, not on the steeper angle at the bottom.
Yes, I figured the same, and it does appear there is a light and aggressive angles based on position.
I also ordered and received a new spring with a higher comp rate. It's running quite well now but I can just mark the settings and return to them if needed.
I'll wait for the pins to arrive and try both one of these weekends.
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Where did you get the spring from? I could use one...
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Where did you get the spring from? I could use one...
Sent from my XT1097 using Tapatalk
Here you go
https://www.mcmaster.com/#9657k324/=16zhq8x (https://www.mcmaster.com/#9657k324/=16zhq8x)
You get three and I believe it was around nine bucks for the package. Might be too stiff but they are easy to change. I am hoping that, combined with the new pin(s) I am getting from the UK, it will be more of a gradual increase in both fuel and boost ending in decent HP/torque and EGT's below 1200F.
The pins won't arrive for a bit yet and I'm waiting till they do.