Quote:
Originally Posted by 330eJL
i’ve never tried 0-200. I’ve only done 1/4 mile runs and 100-200. i just don’t have a place to do 0-200.
Nice! please share how you can avoid throttle closure. can you share an excel file with that graph?
|
330eJL Hi,
The key to avoid throttle closure is keep DME_BT above ECU_PSI. When ECU_PSI higher than DME_BT, throttle always close. I just knew this info from one of JB4 tuner.
From my understanding ECU_PSI is boost that JB4 tell ECU and DME_BT is boost target from ECU. Target must more than current boost (that ECU think). JB4 use this to control the throttle open-close. Normally, other cars like 330i, m340i DME_BT usually above ECU_PSI then no throttle closure close issue but our platform 30e is not like them. I don’t know why.
You’ll see my graph comparison that when throttle closes, boost2 less than boost (pre-boost). When throttle opens, boost2 very near or equal to boost (pre-boost) and overall boost is much more stable. Someone said, there is useless of making a lot of boost but boost2 is low. Here is what Terry describe boost2 in JB4Tech.
Quote:
|
Boost2: Pressure behind the throttle body in the intake manifold. This is generally a “better” indication of how much boost the engine is actually under. Normally Boost2 will mirror Boost unless the throttle blade is closing enough to limit manifold boost.
|
More info here
here
I accidentally knew the technique to keep ECU_PSI from Terry. I have to tell you that I’m not understand the WGDC, PID, FF things. But the factor that control the ECU_PSI are FF and Duty Bias.
FF and Duty Bias are the same thing. FF is overall adjustment effect to all RPM. Duty Bias is adjustment for each RPM.
Adjusting FF and Duty Bias lower will make ECU_PSI lower. I adjust FF from 50 to 20, almost ESU_PSI is below DME_BT accept in the middle of 3rd gear. Then I adjust Duty Bias on high RPM lower to keep ECU_PSI on all RPM and all gear to be lower than DME_BT.
Please note that after adjusting FF and Cycle Duty, boost will be lower (because ECU_PSI is lower). You should dial more additive boost to keep boost as high as before but beware of Trims max.
Check the attached for before-after graphs and settings and also excel files.