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Thread: Need help on downshifting issue.

  1. #1
    Junior Member
    Join Date
    Sep 2007
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    49

    Default Need help on downshifting issue.

    have attached my current tune below.
    I am currently trying to figure out how to make my transmission down shift from 3rd to->2nd from 55mph to 78mph over 65% tps. I have tried changing the throttle kickdown table. I haven't messed with the down shift part throttle table as of yet as I didn't know how that would affect it. I wanted to get some advice first as what I was doing wrong, or where I needed to be looking.
    Thanks for any help!
    Robby
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  2. #2
    Lifetime Member SSpdDmon's Avatar
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    Jun 2005
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    1,558

    Default

    IIRC, throttle kickdown is pretty much for WOT. The part throttle tables are where you need to make your changes.

    The way I usually read the downshift tables is:
    Assume the value of the 50% tps cell is 30mph. So, when you're going 30mph, you will have to apply 50+% throttle to get the trans to downshift.

    If you're going to be changing the trans tables, check the spreadsheet I made in the trans forum. It'll help you prevent crossing the upshifts/downshifts and torque converter tables.

  3. #3
    Junior Member
    Join Date
    Sep 2007
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    Default

    Thank you for sharing that! It makes a lot of sense now
    Robby

  4. #4
    Joe (Moderator) joecar's Avatar
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    Apr 2003
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    28,403

    Default

    Remember these 2 things:
    - upshift tables: operating point must cross to above the curve to trigger upshift;
    - downshift tables: operating point must cross to below the curve to trigger downshift;

    It doesn't matter if the operating point moves vertically or horizintally.

    I moved this to the trans section.


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