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Thread: Throttle body set screw

  1. #1
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    Default Throttle body set screw

    How do you determine what the proper setting is for the idle speed set screw? I've installed a new BBK throttle body, performed a RAFIG and AUTOVE, but it would seem everything is hinged on the throttle plate being set at proper opening prior to all this. Is there a correct method to determine where the screw should be set? Trying to get my ducks in a row, any help appreciated. Thanks.

  2. #2
    Lifetime Member SSpdDmon's Avatar
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    You log IAC steps. When the car is up to temp, they should be ~70 steps.

  3. #3
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    Thanks for the reply. If I have a cable driven TB, do I need to crack the plate any for bypass air?

  4. #4
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    I think I found the answer in this post

    http://forum.efilive.com/showthread.php?t=4219&highlight=log+iac+steps.

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    did you change the effective area scalar?

  6. #6
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    No, I hadn't changed the value. Thank you for bringing it to my attention. According to what I've found on the forum to determine the effective area scalar-

    Area = pi * R ^2

    R=1/2D, pi= 3.1416

    A= 3.1416 * (1/2D) ^2

    For 80 mm A = 3.1416* (1/2 * 80 ) ^2 = 5026.56 sq mm

    Units for B4349 are %/sq mm

    100%/5026.55 sq mm= .0199 %/sq mm for the 80 mm TB

    This value should be entered into B4349 (ETC Throttle Area Conversion)

    Does this look right?

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  8. #8
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    Thanks again for your input. That's a great spreadsheet. After I've changed the value I need to rerun RAFIG and AutoVE, Correct?

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