how-to: ECU-based direct boost control
#782
ok seeing this looks like the post to put the question i will ask here. ok first the basics. I have a jdm 8MR running a 3 port boost solenoid. since we have two solenoids i connected the 3port to the black one... which corresponds to the 2nd BWDC tables in ecuflash. 2ndly i am using the livemap version of Tephra 510 rom. i have the TBEC turned off. the load i am logging is the temp compensted 2 byte load.
ok the question are
1) looks like the WGDC Mut 86 only shows the dutycycle from table 1 of BWDC... even though i am running off table 2. is there a way to log table 2 instead of table 1.
2) all the threads i have read which talk about bdel say that it tapers off higher rpm... but during logs it looks like i can run 159 (159+110=270) all the way down and achieve 25PSI boost is that correct?
ok the question are
1) looks like the WGDC Mut 86 only shows the dutycycle from table 1 of BWDC... even though i am running off table 2. is there a way to log table 2 instead of table 1.
2) all the threads i have read which talk about bdel say that it tapers off higher rpm... but during logs it looks like i can run 159 (159+110=270) all the way down and achieve 25PSI boost is that correct?
Code:
rpm BWDC BDEL 500 100 159.375 1000 100 159.375 1500 100 159.375 2000 100 159.375 2250 100 159.375 2500 100 159.375 2750 43 159.375 3000 43 159.375 3500 44 159.375 4000 45 159.375 4500 45.5 159.375 5000 47.5 159.375 5500 51 159.375 6000 55 155 6500 57 150 7000 57 145
#783
It's not so much that load drops off, even though it does, it is more you want it to drop off as you are outside the turbo's efficiency and are creating a lot of heat which could lead to high EGTs or detonation. Things like o2 dump, less restrictive exhaust and ported head components will allow for more boost up top.
The recommendations for the TBEC should be to turn off upward correction when tuning. Having downward correction is almost MORE important during tuning that when the car is tuned.
#785
you should, i had one local i did a boost leak test had his load drop from 280 to 240-250 at the same boost after fixing a few big boost leaks. Most common problems i have found is TB seals (known issue - and i have seen this be an issue on evos as low as 20k miles) and people using the wrong size boost/vacuum lines.
Last edited by MR Turco; Aug 26, 2009 at 06:51 AM.
#786
you should, i had one local i did a boost leak test had his load drop from 280 to 240-250 at the same boost after fixing a few big boost leaks. Most common problems i have found is TB seals (known issue - and i have seen this be an issue on evos as low as 20k miles) and people using the wrong size boost/vacuum lines.
#787
What WGDC correction intervals are people running? I know mrfred recommends 1 but I have an Ingersoll 3-port solenoid that is very sensitive to error correction. I want to raise my interval to stabilize the up/down WGDC% changes. Just wondering if anyone else has tried a longer interval.
#788
#789
Thread Starter
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From: Tri-Cities, WA // Portland, OR
What WGDC correction intervals are people running? I know mrfred recommends 1 but I have an Ingersoll 3-port solenoid that is very sensitive to error correction. I want to raise my interval to stabilize the up/down WGDC% changes. Just wondering if anyone else has tried a longer interval.
#790
I already have small correction values (my highest correction -3% for +3.1 psi). I saw that some people are using correction intervals of 2 or 3 for the GM 3 port. So I figure the Ingersoll might benefit from a higher interval as well.
#791
#793
-3.0888 0
-2.7027 0
-2.3166 0
-1.9305 0
-1.5444 +1.0
-1.1583 +0.5
-0.772201 0
-0.3861 0
0 0
0.3861 0
0.772201 0
1.1583 -0.5
1.5444 -1.0
1.9305 -1.5
2.3166 -2.0
2.7027 -2.5
3.06467 -3.0
With an interval of 1, my boost is pretty good but I still get some oscillation between 23-25 psi (desired is 24.1). My boost curves are actually the best when I zero out my BEC. But I prefer to have some closed loop feedback.
#794
can you graph and post the boost oscillation you are talking about? It sounds like your baseline WGDC is off if you are getting that much oscillation.
One thing to try is build in an under and overshoot buffer. What i do is the follow:
...
-1 2
-.9 0
0 0
.9 0
1 -4
...
This essentially gives me a -1 to 1 psi buffer where correction does nothing. I use the correction for extreme variation, so when it is too low or too high. I tune the car enough to change season to season variations anyway.
One thing to try is build in an under and overshoot buffer. What i do is the follow:
...
-1 2
-.9 0
0 0
.9 0
1 -4
...
This essentially gives me a -1 to 1 psi buffer where correction does nothing. I use the correction for extreme variation, so when it is too low or too high. I tune the car enough to change season to season variations anyway.
#795
can you graph and post the boost oscillation you are talking about? It sounds like your baseline WGDC is off if you are getting that much oscillation.
One thing to try is build in an under and overshoot buffer. What i do is the follow:
...
-1 2
-.9 0
0 0
.9 0
1 -4
...
This essentially gives me a -1 to 1 psi buffer where correction does nothing. I use the correction for extreme variation, so when it is too low or too high. I tune the car enough to change season to season variations anyway.
One thing to try is build in an under and overshoot buffer. What i do is the follow:
...
-1 2
-.9 0
0 0
.9 0
1 -4
...
This essentially gives me a -1 to 1 psi buffer where correction does nothing. I use the correction for extreme variation, so when it is too low or too high. I tune the car enough to change season to season variations anyway.