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Thread: Missing torque reduction tables in E39A?

  1. #1
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    Default Missing torque reduction tables in E39A?

    Im working on my own personal vehicle, a 13 buick GS with E39A ecm, and a 6spd manual.

    I feel there are some VSS, or gear based torque reduction tables that I can not find in EFI live.

    During my work on the car, a typo resulted in a change in output shaft pulses per revolution (which cut the speed in half). On the test drive with this file, I noticed a terible lag in 1st gear that was gone at 5mph on the speed (10mph actual speed). The car had no power at all untill 30mph (60mph actual speed). I noticed on the cluster that at 30mph it thought I was still in 2nd gear, (the upshift light), when really in 4rth. Fixing the output shaft pulses brought all concerns back to normal, but there is a deffinate torque reduction
    still in 2nd gear (there in stock trim as well). I believe this torque reduction to be vehicle speed based, or on what the ECM "thinks" which gear it is in.

    The "fat fingered" change in the output shaft pulse is when lead me to this. But again, now knowing the torque reduction is there I can feal it no matter what I change in the EFI file.

    Ill try and post the file later. Just looking for some quick info, it its out there right now.

  2. #2
    Lifetime Member Boost's Avatar
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    Great info, thanks for sharing your findings! I also agree that there is some phantom reduction somewhere, but I have not been able to pinpoint it. These engines / controllers are leaving SO MUCH on the table right now - I'd love to unleash it with EFILive and catch up to the numbers they are hitting in Europe.
    '01 Z28 LS1 / T56
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  3. #3
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    I believe I have found it. "Command Power, Mode" I throught it was engine speed, but it is in vehicle speed. I suspect this is it. Actually limiting throught angle based on speed. Im going to try and mess with this a bit and see what happens LOL

  4. #4
    Lifetime Member Boost's Avatar
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    Let me know! I will try it too
    Last edited by Boost; August 11th, 2013 at 10:39 AM.
    '01 Z28 LS1 / T56
    7.59 @ 94.45 (1/8 mile)
    YouTube channel
    '02 C1500 L59 / 4L60E
    8.24 @ 85.08 (1/8 mile)
    www.lsxnos.com

  5. #5
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    Quote Originally Posted by Boost View Post
    Let mw know! I will try it too
    So I did a mass change to those values, and my results are scewed. I must have picked up a bad tank of fuel because the car started pinging, and would cut out.. I went back to my old file, and it did the same.....Went back to stock and ping and cutout was gone, but a deffinate sure, so timing was deffinately being pulled...........Ill try more next fuel tank, i will fill up with 93oct.


    That aside, it did deffinately change the power response. Problem being is it clearly uses these tables for its dashpot function...Raise the lower values too much, and the idle hangs..
    I will tweak them some more once I ensure that those changes were not contributing to the detonation I was hearing.

    I can't believe these cars do not run wide bands from the factory...How prehistoric GM can really be......

  6. #6
    Lifetime Member Boost's Avatar
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    I just realized you may be talking about tables B8802-B8805. Yes these have a lot to do with performance but in my opinion are not the ones limiting max. power (I could be wrong!). These I use for pedal response and for how the power delivery comes in. And yes if you over-do it you can have some bad results. Possibly you are asking for so much torque that your IATs skyrocket? (thus ping).

    Still I will increase the high RPM sections to see if I can escape the "trap of my trap" at the drag strip. But I still think it has to do with the unsupported TCM limiting things...
    '01 Z28 LS1 / T56
    7.59 @ 94.45 (1/8 mile)
    YouTube channel
    '02 C1500 L59 / 4L60E
    8.24 @ 85.08 (1/8 mile)
    www.lsxnos.com

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