I have run the same tune a few days now with and then without MAF. Filtering to my cruise cell of 2000 RPM at 31.9 kPa, LTFTs are running +3-4% in the hot humid afternoon heat without MAF. My tune: 1.5766 gK/kPa
GELF's DYNAIR calc wants to correct by 1.015 factor (plausible)
calc.VET spits out 1.727 gK/kPa (too high)
calc.VEDCA spits out 1.551 gK/kPa (wrong way)
GELF's DYNAIR calc looks the best.
Originally Posted by ACCLR8N
How did you get on in the end, I was able to do some simultaneous calibration of VE and MAF of my idle over Christmas period.
I also did some experimentation with MAF and VE disabled.
With MAF disabled, I set MAF to 1g across the entire frequency range to be sure, MAF is still logged and returns value 1g, but not referenced by thePCM, like wise I set VE table to 0.5g*K/kPa for all cells, E40.SCALEDCORVE returned 0.5 for all and DYNAIR returned very low g/sec values accordingly, but is not referenced by the PCM.
I confirmed if MAF is disabled AIRPERSEC follows DYNAIR (not exactly, maybe some internal algorithm applied), if dynamic air mode is disabled AIRPERSEC follows MAF (again not exactly). With dynamic air mode enabled AIRPERSEC is combination of both, in all my observations and modifications to the tune calibration file, STFT<FT with BEN correction factor is applied with regard to AIRPERSEC.pid. My target was to achieve >0<1% trims on rich bank and +trims on the lean bank, I'm pretty close after 4 iterations, see attached pdf.
The E40.APCYL DMA g/cyl pid from what I observed always follows the minimum AIRPERSEC calculated g/cyl value which is referenced for spark look up table.
One thing was strange when I had made an error in the tune calibration for dynamic air mode to disable VE, I left B2002 re-enable so it was much higher than B2001, anyway DYNAIR returned g/sec values almost 3 times higher than expected, AIRPERSEC still followed the MAF, DYNAIR was not referenced by the PCM, Strange?
My logs attached, so for calibrating MAF and VE simultaneously set B2001 TO 500rpm and B2002 to 400rpm and apply STFT<FT&BEN to AIRPERSEC g/sec values and correct DYNAIR and MAF factors as an average or to rich or lean side which ever is your preference
Short answer: Great with your formulas. If you didn't mash the pedal and let the turbo sing, you would not know you were driving a modified vehicle. My MPG display is even accurate to 1%.
In the end I found the formulas quickly got me to a 6% fuel trim error. To get better than that involved disabling the MAF, nudging in on the VE table by correcting 50%, 25%, 15% and finally hand smoothing out any spikes. MAF fine tuning went very quick following the descending correction scaling and some more hand smoothing. The AIRPERSEC discrepancy you pointed out above may be more pronounced in my car.
I am looking forward to reviewing your logs when I get home tonight.
Oh, and I must say: Thank you very much!
Last edited by ACCLR8N; January 5th, 2015 at 07:12 AM. Reason: Thanks
05 GTO LS2 6spd E40, 70mm front mount turbo on stock long block
Gelf, do you have a recent normal driving loop log? Preferably 30+ minutes? I've found the readings stabilize after 20 minutes of driving. Was probably you that pointed that out to me. I'm comparing average MAF to DYNAIR and LTFT's as a sanity check on my tune. I wish I would have logged my car before modifications.
You got me beat on the idle values. I'm going to blame my aftermarket 60lb injectors for at least part of my discrepancy.
05 GTO LS2 6spd E40, 70mm front mount turbo on stock long block
Sorry I don't, I didn't have any insurance, that's why I spent so much time looking at idle
Well, I am curious to see how your tune lines up with and without MAF enabled. I definitely got different results when I tuned separately vs simultaneous. That final sub-2% variation in the airflow inputs and fuel trims escapes me as my bench mark for the elusive "perfect tune". My MPG is better than stock and I have no driveability issues so last fall I gave up and pulled my wideband.
05 GTO LS2 6spd E40, 70mm front mount turbo on stock long block
I always got unsatisfactory results when I did VE and MAF independently correcting DYNAIR and MAF, because I should have corrected to AIRPERSEC and applied to DYNAIR and MAF
I did some analysis on the logs for VE/MAF/Trims enabled/disabled.
Gelf,
I have been thinking... what car do you have, and what intake manifold does it have...?
Its a Monaro 6.0 VXR, LS2 with E40 PCM, its been modified with stock LS3 heads and stock L76 intake, plus cam
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