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Thread: Excel sheet to find Wideband Transfer function for AFR and EQ ratio.

  1. #1
    Senior Tuner
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    Excel sheet to find Wideband Transfer function for AFR and EQ ratio.

    I do this for remote tuning customers who can't find a pre-defined wideband that matches the one they have.

    Input your voltages and correlated AFR from your wideband's install instructions / documentation and it spits the transfer function out in AFR and EQ ratio.

    Capture.PNG



    https://www.dropbox.com/scl/fi/mffjt...d75mjuw0l&dl=0

    On a side note.. If your vehicle supports it I suggest the AEM OBD2 CAN wideband 30-0334
    Tuner at PCMofnc.com
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  2. #2
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    Often I'll have customers send logs where the wideband clearly isn't matching up with the narrow bands. This is often cause because the voltage out from the wideband or the voltage IN to Hptuners isn't correct. Likely because of some floating ground situation but in all honestly I think most widebands have pretty poor voltage out.

    To help correct this.... I suggest videoing the gauge face and the HPtuners scanner while the engine is running. Randomly stop the video in a few spots and check to see that the value read in Hptuners matches the gauge face. IF it doesn't.. use the above spread sheet and log raw voltage *with no transform, just raw voltage* From that point try to grab the richest spot in your video sample and the leanest spot in your video sample. Input those values into the above spreadsheet and use the new user defined transform.

    When you setup a user defined transform.. take care to setup the sensor, units,etc. You can see the above image for a sample.
    Tuner at PCMofnc.com
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  3. #3
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    Below is a some screen shots. I suspected this customer didn't have his wideband setup. Had him record a video. Took two samples by randomly pausing the video. This is the result.

    You can see that just relying on the predefined transforms and not taking in account poor voltage out/ ground offset issues could be REALLY bad.



    Wideband mismatch.jpg

    2 wb.JPG
    Tuner at PCMofnc.com
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  4. #4
    Advanced Tuner
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    This is good stuff, Thanks Alvin!!
    "I don't care how it runs as long as it chop chops at idle"

  5. #5
    Tuner in Training
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    hey Alvin how can i contact you for more information

  6. #6
    Tuning Addict blindsquirrel's Avatar
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    Quote Originally Posted by [email protected] View Post
    hey Alvin how can i contact you for more information
    Tuner at PCMofnc.com