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Thread: WOT VE Tuning in SD mode

  1. #1
    Potential Tuner
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    Mar 2019
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    WOT VE Tuning in SD mode

    I'm working on tuning the VE table in Speed Density mode on a 99 Camaro SS. I have the everday driving tuned pretty good to match what will be the commanded afr when I switch the MAF back on. But my question is dealing with the WOT tuning. On my megasquirt SD car I'd just tune it to be the afr I want at WOT and everywhere else on the map. But I'm a little confused how I should go about it with the Power enrichment settings that are going to weigh in when the MAF is back on.

    SO do I tune the VE table to match the 14.7 afr everywhere even at WOT and then the PE will add fuel while working with the MAF or do I need to tune the VE to yeild the 12.5 or whatever I need in SD regardless of the MAF and PE settings.

  2. #2
    Advanced Tuner
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    You tune both MAF and SD with PE enrichment active for WOT.
    1997 30th SS. Torqhead 24x, TFS heads, 234/244 cam, 4l80e, Dana 60.

  3. #3
    Advanced Tuner
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    Dec 2011
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    VE and MAF are airflow models. The PCM references the stoich of the fuel, and the desired EQ ratio (stoich/desired afr) so 14.68/12.5 for example. The pcm says ok this much air, this stoich, this desired EQ ratio, I need this much fuel. So you tune based on AFR or EQ error. Just the error of desired vs commanded.
    JTC Performance - Authorized HP Tuners Reseller
    Performance Tuning in the Texas Panhandle

  4. #4
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    Lets back up a bit guys. I understand PE and what it does and how it affects the commanded fueling when a MAF is in use. I know how to tune an SD car without PE. What I need to know is do I tune the VE table in SD mode (without MAF/PE enabled) to be 14.7 in all cells or do I tune it in SD mode to be rich at WOT and lean at idle cruise. This would then essentially eliminate the need for the PE which is just a multiplier of the VE cell to increase/decrease the fueling requirements.

  5. #5
    Tuning Addict 5FDP's Avatar
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    You tune it to match the commanded AFR no matter what.

    If the commanded AFR is the 14.7 for stoich, you are tuning those cells to reach that. If the commanded AFR changes to 12.5 for PE, you are tuning those cells to reach 12.5.

    That is why the VE has a slope/peak. It has lower values at lower rpm and cylinder airmass and has higher values at higher cylinder airmass and rpm.

    There is no need and no want to do it the way you described, you want to have PE active within the calibration.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.