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Thread: FORD MUSTANG "spark IAT Correction vs IAT" table figures????

  1. #1
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    FORD MUSTANG "spark IAT Correction vs IAT" table figures????

    The spark correction starts with 85.00 and goes up to -154.00. I assume this figures must have the decimal 1 digit left. Correct????

    And, when I am changing them, Shall I write the correct figures or still use the mistaken 1 additional decimal digit???

    Regards,

    Murat

  2. #2
    Advanced Tuner Screamn03's Avatar
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    That is not a mistake. Attached is the picture of the table you're referring to, also attached is the multiplier table.

    Why are you changing this? When air temps get excessively hot spark retard needs to take place to keep the engine from detonating. The large number that seems inaccurate to you has the multiplier (based on load and RPM) applied to it which will knock down the final value alot. Remember, when you multiply something by less than 1 the end result is a smaller number.

    Is this Mustang you're working on a completely stock vehicle or does it have modifications done to it and if so what?
    -Michael Rudolph-
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  3. #3
    Advanced Tuner Screamn03's Avatar
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    Apply it to an example, say your IAT is 150*F and you are at 1500rpm and 30% load. Using those two tables the math would look like this:
    -80*0.07= -5.6

    Based on just this info the computer will pull 5.6* of timing based on those load, RPM, and IAT figures.
    -Michael Rudolph-
    2003 Redfire Cobra
    Eaton Powered to a:
    11.301 @ 129 1.68 60' MT DRs
    11.85 @ 124 1.90 60' street tires

  4. #4
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    Might be worth it to just set the multiplier table to 1.0 and set the iat adder table to something realistic then for simplicity sake.
    It doesn't have to be perfect, it just needs to be done in two weeks...

    A wise man once said "google it"

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    Just a FWIW, but it looks like the ECT adder tables have numbers in a high range the the multiplier keeps the final figure realistic as well.
    It doesn't have to be perfect, it just needs to be done in two weeks...

    A wise man once said "google it"

  6. #6
    Advanced Tuner Screamn03's Avatar
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    Quote Originally Posted by Bill@HPTuners
    Might be worth it to just set the multiplier table to 1.0 and set the iat adder table to something realistic then for simplicity sake.
    That would work.

    Only thing to consider is you take a 3D table of spark retard based on Load and RPM and turn it into a 2D table of retard based strictly on temp. 3D is more complicated but gives you more control.

    Why Ford doesn't just make it a 3D single table to begin with I dunno, maybe it's easier to program that way or takes up less memory? Maybe it's just another way to skin the cat....
    -Michael Rudolph-
    2003 Redfire Cobra
    Eaton Powered to a:
    11.301 @ 129 1.68 60' MT DRs
    11.85 @ 124 1.90 60' street tires

  7. #7
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    true. May take a little more work then just 1.0 across the board, but still would probably be easier for most to comprehend & adjust that multiplier table from there.
    It doesn't have to be perfect, it just needs to be done in two weeks...

    A wise man once said "google it"

  8. #8
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    Personally, I would leave the Multiplier table alone for the most part, and just worry with the Base function.

    For 93 octane based vehicles (93 PON = approx. 98 RON), since one is going to obviously increase spark considerably over the factory 87 octane based spark tables, for the Base function, I personally would 0 out anything below 100 ACT, and set the function to retard above 100 ACT (which is what factory is set to anyway).
    Last edited by RWTD; 08-05-2007 at 06:36 PM.
    Formerly known as RWTD

    Toys: '22 Tesla Model S Plaid / '20 Chevy Duramax / ?20 Sea-Doo RXT-X (2)

  9. #9
    Yeah when running a hot spark table you don't really want to add any more based on ECT or ACT.
    Justin Starkey
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