how-to: ECU-based direct boost control
Mar 16, 2009 | 11:30 PM
#631
+1
small means boost error is checked and acted upon more frequently
1 works - i used to use 1
most people use 2 or 3
if you use 1, then make sure you additive or subtractive numbers in TBEC are SMALLER, ie:
lots of smaller changes is better than fewer bigger changes...
small means boost error is checked and acted upon more frequently
1 works - i used to use 1
most people use 2 or 3
if you use 1, then make sure you additive or subtractive numbers in TBEC are SMALLER, ie:
lots of smaller changes is better than fewer bigger changes...
Mar 17, 2009 | 01:24 AM
#634
How should I change BDEL tables? I mean, the entire column is 159.4 on both BDEL tables.
I had my boost setup using only WGDC table and hit a peak of 24/25psi tapering to 20ish by 7300, it just seemed oscillate a lot, my DLL power graph looked more like crazy, like a seismograph reading.
I had my boost setup using only WGDC table and hit a peak of 24/25psi tapering to 20ish by 7300, it just seemed oscillate a lot, my DLL power graph looked more like crazy, like a seismograph reading.
Mar 17, 2009 | 04:31 AM
#636
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From: Tri-Cities, WA // Portland, OR
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.
Mar 17, 2009 | 09:27 AM
#637
More boost is generated in higher gears because the turbo loads up more effectively. You have the boost system tuned to pull out a ton of WGDC when strong overshoot occurs, so you shouldn't be getting 4 psi overshoot. I suspect that the WGDC correction interval is too high. I used to use "2", but now I use "1". I recommend trying either one of those.
Mar 17, 2009 | 10:33 AM
#638
Which system would I need the JDM map for? psi based right? Isn't that the most stable and ideal way to go about things? I'm planning on ordering my EVO X map today.
Mar 17, 2009 | 06:42 PM
#640
If you are using PSI based then you don't use BDEL.
Regardless, BDEL stands for Boost desired engine load, it is the target load value that is used in the ECU Load based boost control. Current load - BDEL = load error. Then error is used to look up the correction factor(TBEC) that is add/subtracted from base line duty cycle (MWGD).
Oh one last thing BDEL has an offset, Boost control Load Offset (BCLO), so if BDEL is 159.9 and BCLO is 100, then the target load is 259.9.
Regardless, BDEL stands for Boost desired engine load, it is the target load value that is used in the ECU Load based boost control. Current load - BDEL = load error. Then error is used to look up the correction factor(TBEC) that is add/subtracted from base line duty cycle (MWGD).
Oh one last thing BDEL has an offset, Boost control Load Offset (BCLO), so if BDEL is 159.9 and BCLO is 100, then the target load is 259.9.
Mar 18, 2009 | 05:09 AM
#642
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From: Tri-Cities, WA // Portland, OR
Stock load-based boost control tends to try to push boost higher in hot weather. My psi-based boost control tends to cause boost to shoot higher (sometimes too high) in cold weather. I believe the tephra's latest ROM has a WGDC correction vs IAT that stops the overshoot in cold weather.
Mar 18, 2009 | 01:11 PM
#644
Right click on BDEL tables, edit, change scaling to psia8. It'll show values in PSI for direct (psi based) boost control. They are the same exact tables as "Baseline Boost", use whichever, changing one set changes the other.
Mar 18, 2009 | 03:12 PM
#645
good news, I kept the same tables as previously posted, only changing the correction interval from 2 --> 1 and it has fixed the problem. 5 gear is perfectly drivable at WOT now.
thanks again for the pointers everyone had, i greatly appreciated the help!
thanks again for the pointers everyone had, i greatly appreciated the help!