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Thread: Basic tuning question MAF

  1. #1
    Tuner in Training
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    Basic tuning question MAF

    It's about a E39.
    Why the engine develops power if you changed the MAF Map?

  2. #2
    Senior Tuner cobaltssoverbooster's Avatar
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    Matching required afr to commanded afr makes power by minimizing amount of corrections to fuel map during driving.
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  3. #3
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    what is the difference between required afr and commanded afr in the pcm ?

    Where can i find the maps for required and commanded afr on the regal gs (E39) ?
    Last edited by mcb78; 11-12-2013 at 02:49 PM.

  4. #4
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    I think he meant the required AFR that it takes to make power. The commanded is what the computer wants/thinks the AFR should be. In a nutshell the commanded AFR is stoich normally and you can find the comm afr for WOT in the PE table. Actual AFR would be what the wideband shows. Get them to match.
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  5. #5
    hi, I'm new to this forum.
    I also have a thing concerning the MAF on the regal.
    Is it possible the thing is maxed out as 200g/s = 9000Hz? so i'm locked in power output, if I lower the MAF Curve this helps a lot, but correcting the AFR then is pretty messy.

    Thanks

  6. #6
    Senior Tuner cobaltssoverbooster's Avatar
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    Iirc the regal air box I have uses a smaller diameter tube. When I put just the sensor in my lhu balt it runs fine. Maybe you just need to put it in a bigger tube to slow the air down. Fast moving air will max the sensor out faster.
    Measure the maf sensor meter tube to compare.

  7. #7
    of course this is one solution to it.

    but I was stunned on the point that it might be a software limit at 200g/s...but for hell I can't find anything like this.
    then I catched the point that the frequency won't go past 9kHz... in The MAF table it is set up Until 15kHz... and the max MAF fail freq limit is anywhere around 14000... so why should gm set the limits that wide
    Last edited by dertobi; 11-22-2013 at 08:04 PM.

  8. #8
    can anybody confirm this?