how-to: ECU-based direct boost control
I've been trying to get this dialed into my car for the last couple of days. WOT 3rd gear pull works like a charm, BoostError is ~0.0-0.5 all the way through the boost curve to redline.
5th gear is a different story though, if im on the freeway at ~5k and I go WOT the boost will overshoot and BEC doesnt take affect. My target is 21psi but it will overshoot to 25+ on a rolling 5th gear pull. I have included my tables, any pointers would be awesome...I've tried lowering the WGDC but then it becomes too low for boosting in other gears. This is for a bbk on 91, no meth yet so keeping boost reasonably safe.
5th gear is a different story though, if im on the freeway at ~5k and I go WOT the boost will overshoot and BEC doesnt take affect. My target is 21psi but it will overshoot to 25+ on a rolling 5th gear pull. I have included my tables, any pointers would be awesome...I've tried lowering the WGDC but then it becomes too low for boosting in other gears. This is for a bbk on 91, no meth yet so keeping boost reasonably safe.
You are way to high of a WGDC too early. I can see 25 PSI by 2750 on my stock turbo in 5th gear. V6 now has the ability to do gear based boost control, so that helped immensely. You will either have to lower your duty cycle and expected boost dramatically at 2750 and 3k (and maybe 3.5) or just be smart enough to not mash the pedal all the way in 5th until you can get gear based control.
Notice 5th gear in the tables here... I've even lowered it since this pic was posted...
https://www.evolutionm.net/forums/6808179-post153.html
I personally prefer to let the correction v tps table remain stock after I'm done tuning boost.
You are way to high of a WGDC too early. I can see 25 PSI by 2750 on my stock turbo in 5th gear. V6 now has the ability to do gear based boost control, so that helped immensely. You will either have to lower your duty cycle and expected boost dramatically at 2750 and 3k (and maybe 3.5) or just be smart enough to not mash the pedal all the way in 5th until you can get gear based control.
Notice 5th gear in the tables here... I've even lowered it since this pic was posted...
https://www.evolutionm.net/forums/6808179-post153.html
You are way to high of a WGDC too early. I can see 25 PSI by 2750 on my stock turbo in 5th gear. V6 now has the ability to do gear based boost control, so that helped immensely. You will either have to lower your duty cycle and expected boost dramatically at 2750 and 3k (and maybe 3.5) or just be smart enough to not mash the pedal all the way in 5th until you can get gear based control.
Notice 5th gear in the tables here... I've even lowered it since this pic was posted...
https://www.evolutionm.net/forums/6808179-post153.html
Many people run the mitsu 3 bar because its easy to do and plug and play. If you go with PSI cut you are limited to about 29 psi. People like me can and do run 29psi so I'd want my boost cut at 35psi (I wouldn't use it, but for arguments sake). Thus load based is still a better option because you aren't capping yourself with the mechanical limit of a pressure sensor.
Many people run the mitsu 3 bar because its easy to do and plug and play. If you go with PSI cut you are limited to about 29 psi. People like me can and do run 29psi so I'd want my boost cut at 35psi (I wouldn't use it, but for arguments sake). Thus load based is still a better option because you aren't capping yourself with the mechanical limit of a pressure sensor.
mrfred,
What is the correction interval for? I had it set to 3, I just wanted to know what it helped with and what not?
Also, you're suggesting, if we have tuned everything successfully until step 3, we can try your settings for step 4 and 5?
What is the correction interval for? I had it set to 3, I just wanted to know what it helped with and what not?
Also, you're suggesting, if we have tuned everything successfully until step 3, we can try your settings for step 4 and 5?
Last edited by Inprogress; Mar 16, 2009 at 11:03 PM.
Many people run the mitsu 3 bar because its easy to do and plug and play. If you go with PSI cut you are limited to about 29 psi. People like me can and do run 29psi so I'd want my boost cut at 35psi (I wouldn't use it, but for arguments sake). Thus load based is still a better option because you aren't capping yourself with the mechanical limit of a pressure sensor.
if the sensor fails and you get a 0psi back, then so long as your TBEC doesn't have anything in the "underboost" then it wont add any wgdc - so it will just follow the baseline wgdc...
I think that's correct..
I think that's correct..
I personally don't agree with the tuning method used in your tables at all.
What type of fuel are you running on this setup? I'd say your settings are a little too high for E85 and a little to low for Q16.
My recommendations if you are having troubles - Change all but the top -3.1 psi to what it was and correction to 0. Change th bottoms back to normal and just make them all -3 adjustment.
Less WGDC at 2500 and even less at 2750.
Change the baseline boost table to reflect what boost you actually expect at that RPM, especially in the lower RPM. Change the scaling so you can easily visualize what you are actually aiming for.
What type of fuel are you running on this setup? I'd say your settings are a little too high for E85 and a little to low for Q16.
My recommendations if you are having troubles - Change all but the top -3.1 psi to what it was and correction to 0. Change th bottoms back to normal and just make them all -3 adjustment.
Less WGDC at 2500 and even less at 2750.
Change the baseline boost table to reflect what boost you actually expect at that RPM, especially in the lower RPM. Change the scaling so you can easily visualize what you are actually aiming for.
^ I'm not having any problems. This is my example of how these can be tuned. 0.4 psi steps are a waste of time in my opinion. Correction lags behind boost anyway with this method of boost control, so there is no need for fine psi resolution. This is easier and works fine as you can see in the screenshots.
The lower the number the more often the boost error is checked and the necessary adjustment to WGDC is made. I think the lowest that works is 2. 1 should work with Tephra's v6, afaik.
If you want it checked and adjusted often, use smaller numbers in error correction.
More exact numbers in ms are posted somewhere in this thread i think. Just search.
If you want it checked and adjusted often, use smaller numbers in error correction.
More exact numbers in ms are posted somewhere in this thread i think. Just search.