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Thread: .5afr leaner in HPT than what's on the gauge

  1. #1

    .5afr leaner in HPT than what's on the gauge

    So I understand I need to setup the custom PID. I'm using the AEM UEGO wideband. It reads 10-18afr

    The formula reads:

    volts/.625 + 10 + (.5)

    Is that correct?
    2007 Cobalt SS 2.4 5spd SUPERCHARGED

  2. #2
    volts/.625 + 10.5 I believe would be a more correct way. Whether the .5 is the right correction number for your .5 difference between the scanner and HPTuners, maybe. I adjusted my "10" number to correct mine, but some have adjusted the .625 part. You will likely have to experiement a bit. Have a look at this thread and see if it helps at all http://www.hptuners.com/forum/showthread.php?t=20433
    Last edited by IndeedSS; 01-07-2009 at 12:08 PM.
    2010 Camaro SS LS3
    SOLO highflow cats|VMax ported TB|Vararam

  3. #3
    Senior Tuner
    Join Date
    Nov 2002
    Location
    Central Florida
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    Any offset in addition to the base AFR (10) must
    be an attempt to correct ground errors and these
    will vary from vehicle to vehicle, wideband to
    wideband. You can't even count on the offset being
    self-consistent (primarily driven by heater current
    and that, varying w/ exhaust gas and outside temp).
    You should measure endpoint readings (force the
    WB to output 0.000V, record raw volts for 10:1;
    force WB output to 5.000V, record raw volts for
    18:1; ideally, try out 1, 2, 3, 4 as well to get an
    idea of any nonlinearities and fill in a custom PWL
    function for the PID) so you know for sure on your
    hardware.

  4. #4
    Senior Tuner 5_Liter_Eater's Avatar
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    Nov 2005
    Location
    Houston, TX
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    3,968
    Quote Originally Posted by jimmyblue View Post
    Any offset in addition to the base AFR (10) must
    be an attempt to correct ground errors and these
    will vary from vehicle to vehicle, wideband to
    wideband. You can't even count on the offset being
    self-consistent (primarily driven by heater current
    and that, varying w/ exhaust gas and outside temp).
    You should measure endpoint readings (force the
    WB to output 0.000V, record raw volts for 10:1;
    force WB output to 5.000V, record raw volts for
    18:1; ideally, try out 1, 2, 3, 4 as well to get an
    idea of any nonlinearities and fill in a custom PWL
    function for the PID) so you know for sure on your
    hardware.
    I agree. Just make sure you do this at the operating voltage. IE: without the engine running you only have ~12V. with it on there is ~14V. It's important to take these measurements at ~14V (engine on).
    Bill Winters

    Former owner/builder/tuner of the FarmVette
    Out of the LSx tuning game