EMU Black Boost Control - Rb25 Swap

Hi Guys,

i was recently at the track, testing my half tuned Rb25 swapped E36. Now it went pretty good to be honest, but i do have a in depth question on the boost control. Since my tuner is pretty busy and i really prefer to do the rest of the tuning myself, i could use a little help here. 3 pictures attached

1. boost control from my tuner

2. my approach

3. snippet of the log file

I used the open loop Control. the idea behind my approach was, to get the most out my turbo while building up boost, then hold on high boost (which is not high at the moment, but i want it to work well before upping the boost) and then taper out at the end of the rev band. I dont want to hit the limiter with everything i have, so though of decreasing boost a little in the end.

As you can see from the log file, i dont runn a lot of boost. To me it feels like the turbo is taking way too long to build up boost. I do have relatively long piping to the intake manifold (which is stock) but the diameter is not that big, so therefore that should compensate for the speed of the air (restricting peak power, but i dont really mind that) .

I know that the boost control itself wont have a huuuge impact, but i think somehow my version could work a little better at lower rpms, since im helping the wastegate to build up boost earlier in the rev band. In addition i filled the data for the "dc error corr" table to somehow correct the values when things are too far off. Testing on the values is a must, thats absolutely true, but i just want to confirm that my approach is not entirely useless..

Its an build Rb25, Forged Internals, 9:1, GT3582R Turbo, 980cc Inj.

Thanks in Advance for any help! (My english is a little rusty, sorry for that..)

David,

If the goal is to use feed forward values which increase duty when boost is below target, and decrease boost when it's over target, the DC error correction is a good place to do that, and I agree it would be an improvement.

I wouldn't put huge numbers in the main duty table i.e. 95% in a spool area, because in some condition, perhaps in a high gear going up hill, that may cause massive over shoot of your boost target.

If you want to be more aggressive, you can put higher values in the DC error correction table. For example +100% until you're 70 kpa below target, and taper that down to zero near target. That way you get max solenoid duty cycle to help spool, but only until the turbo gets going.

You can also do the inverse, for example if boost is 50 kpa over target, -100 duty cycle correction to shut boost control down.

And I would suggest keeping those corrections relatively small when boost is near target, to avoid causing oscillations. It will take some adjustment, but you're on the right track.

Hey Mike,

thank you very much for your response, that helps a lot! I will test the settings at the track and will post the results and the things i learned afterwards.

Awesome, you're welcome!