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Thread: PE does not equal commanded, I am thinking IVT?

  1. #1
    Tuner BigTuner's Avatar
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    PE does not equal commanded, I am thinking IVT?

    Hello,

    I have a 2012 ZL1 and I have been tuning my SD and MAF using a wideband and AFR error histograms and have everything dialed in to where my commanded and actual AFRs are the same. The problem is that my commanded AFRs do not match my PE values, they are always a bit richer. From my research this is due to the IVT tables adding fueling on top of the PE tables to give the final commanded AFR, the only way I see to get PE to match commanded would be to set the IVT tables to 1 throughout but I don't think I want to do this. Without messing with the IVT it seems there is no direct way to drive the exact AFR I want, is this just something I have to live with and do some slight PE rape to get the exact AFRs I want? My VE and MAF stuff is completely dialed in so it wouldn't be full on rape but after all the calibration work I have done it seems sad not to be able to directly drive PE AFR changes as I will still have to do some some trial and error scanning to get the AFRs where I want them.


    How do others deal with this problem?

  2. #2
    Advanced Tuner jsllc's Avatar
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    Sep 2015
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    Bozeman, MT
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    Do not have that issue. Did not adjust the IVT. It is all related to what you did with MAF and VVE
    2012 ZL1 - Maggie Heartbeat, Port & Polish Heads, Custom Cam, Custom rotating assembly, steel sleeved LS9, No NOS and No water meth. 16psi
    810rwhp and 820rwtq 91 Octane 6400 rpm
    948rwhp and 951rwtq 105 Octane 6400 rpm
    999rwhp and 997rwtq on 60% Ethanol 6400 rpm

  3. #3
    Tuner BigTuner's Avatar
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    Okay thanks I guess that is good news, I will go back over my tuning and make sure I didn't miss anything.

  4. #4
    Advanced Tuner jsllc's Avatar
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    Sep 2015
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    need to post the tune for anyone to really help.
    2012 ZL1 - Maggie Heartbeat, Port & Polish Heads, Custom Cam, Custom rotating assembly, steel sleeved LS9, No NOS and No water meth. 16psi
    810rwhp and 820rwtq 91 Octane 6400 rpm
    948rwhp and 951rwtq 105 Octane 6400 rpm
    999rwhp and 997rwtq on 60% Ethanol 6400 rpm