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Thread: What is an acceptable AFR variation between banks

  1. #1
    Advanced Tuner angrygoat's Avatar
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    Oct 2008
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    New Baltimore, MI
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    What is an acceptable AFR variation between banks

    Im sure my readings are a little skewed because Im using two different brand WBs. I have an NGK in one bank and a Dynojet in the other. I was curious what is an acceptable variation between the two banks. I seem to be off anywhere from a half point to a full AFR point.

    TIA
    Joe
    2006 M6 GTO
    APS TT
    10.76@131

    "The goal of tuning is for the tune to run well enough you dont need any corrective mechanisms"

  2. #2
    Senior Tuner
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    Dec 2004
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    Laurel, MD
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    if you got two WB's then first you need to figure out your calibration, or you're gonna be running in circles not knowing which one is telling the truth, and by how much the other one is off.

  3. #3
    Advanced Tuner angrygoat's Avatar
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    Oct 2008
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    Im not sure I understand you Marcin. By calibration, are you referring to my tune or the transfer function for the widebands? Im more likely to believe my NGK over the dynojet but when I force the computer into closed loop via the 2-way controls the factory o2s verify this with a very high positive fuel trim for bank 2.

    I am going to check my valvetrain and plugs tonight. I actually drove it last night and feels like there is a misfire which should account for the lean if its on bank 2. I have retorqued my intake and exhaust manifolds, retorqued the down pipes, and sprayed carb cleaner all over the intake and vacuum lines and have not come across anything that seems to be a leak. We'll see tonight
    Last edited by angrygoat; 08-17-2010 at 07:07 AM.
    Joe
    2006 M6 GTO
    APS TT
    10.76@131

    "The goal of tuning is for the tune to run well enough you dont need any corrective mechanisms"