Audi RS2

[z0tya]

what kind of performance box do you use?

[AVP]

racelogic perfomance box. same company that makes the vbox.

[GintsK]

well without any headphones for knock at least now, i will have to guess the MBT

MBT and knock margin is different things. It can or can not overlays. At high boost levels most plausible it overlays. And in this case knock listening is enough, but MBT is not reached.

[AVP]

so you are saying that on low boost levels you can more easily run on MBT and knocking would never be a problem, but on high boost levels the amount of boost is increasing compression ratio to a point where the MBT is not reached but the knock threshold is?

[rob@vems.co.uk]

Pretty much spot-on.
If you have ever heard the expression that the timing is "det limited" they're saying that they couldn't run the advance to MBT because the engine would detonate before that point.

[gunni]

That goes for most engine setups.
They are usually det limited as the load goes higher and because people can still gain power with higher load and without reaching MBT for that load and rpm they do. As long as the tuning is safe there isn´t anything wrong with that.

[AVP]

For better idle control i changed a coolant bin on the map to allow the use of a temp of 80C CLT. VEMS seems to raise the idle speed when the engine is hotter for some reason, and although it makes sense as the fan will be kicking in sooner and it might cause a drop in idle, i didnt like it when the idle was around 1000-1050rpm. So now i can use one more value on the idle PWM and so can retain the idle low.

The PID control i use on the idle settings does the job nicely in keeping it steady. Ill report when i have more tests!

[AVP]

much improved idle with even more fine tuning!

on the other side, i managed to connect to the 1.1.27 using vemstune for the first time. I must say that it did crash a couple of times to begin with,but it worked in the end. The spark gauge was not working though.

still like the megatune enviroment a bit more though

[AVP]

Doing some datalogs after removing the MAF i noticed that i was getting overboost cutout. I dont understand why,but i was reaching my set limit of 310kpa.

now i have resetted the boost figures and everything works fine again.

I also noticed that in 1.1.27 the boost offset figure goes from 16 to 14, and does not allow me to use figure 15.However it does reduce the amount of boost i see when i do change it to 15 and burn to ECU.... strange..

[MWfire]

Doing some datalogs after removing the MAF i noticed that i was getting overboost cutout. I dont understand why,but i was reaching my set limit of 310kpa.

Becouse MAF is restrict for air flow.

[AVP]

i have really noticed that after 5800-6000rpm the lamda becomes really low,even with the VE remaining stable.It goes down to 0.70.So i started reducing the VE values and got it to 0.73-0.75.(from 250-280kpa)

Does that mean that the cams are running out of ability to keep the volumetric efficiency going? or is it that the turbo is running out of juice on those areas?

[AVP]

also on one of my 3d gear pulls, i noticed that i had a minor misfire. When i went back to logviewer, y dwell was 3.36ms which is what it is normally and the rpm signal just went to 453478rpm and came back.

anyone has a clue what that means?

[gunni]

i have really noticed that after 5800-6000rpm the lamda becomes really low,even with the VE remaining stable.It goes down to 0.70.So i started reducing the VE values and got it to 0.73-0.75.(from 250-280kpa)

Does that mean that the cams are running out of ability to keep the volumetric efficiency going? or is it that the turbo is running out of juice on those areas?

What is the compressor inducer size, your injector size and duty cycle and is the intake temparature rising rapidly?

Most likely it´s the cams/head package running out of breath or just to much backpressure from the turbine.

[gunni]

also on one of my 3d gear pulls, i noticed that i had a minor misfire. When i went back to logviewer, y dwell was 3.36ms which is what it is normally and the rpm signal just went to 453478rpm and came back.

anyone has a clue what that means?

That sounds like a trigger error.

[AVP]

the turbo is the GT3071R with 0.63AR
compr. inducer size is 53/7x i dont remember..

injector size is 440@3bar and audi has a 3.8bar fuel pressure regulator. I dont know how to calculate the injector duty cycle.

intake temperature is actuall pretty good. at the beggining of the run is 13C, goes to 18.9C and can rise to 38C(but today it only wnet to 34C).

i definitelly have quite a bit of backpressure from the turbine,as it is concidered to be small.


what does that trigger mean,and should i do anything about it?