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Thread: Help understanding 6R80 OSS v. Pedal Position Tables

  1. #1
    Advanced Tuner 96gt4.6's Avatar
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    Help understanding 6R80 OSS v. Pedal Position Tables

    Hey guys,

    I'm working on playing with the up/down shift speeds on a '15 F150, and wanted to see if I could get a little help clarifying the up/down shift tables on these trucks. I have been using a spreadsheet that was provided on another thread here that converts OSS to engine RPM, but was curious how this table actually works. On the up-shifts, once the OSS in the table is exceeded, the up shift occurs? Same with down-shift, once the actual OSS is below the table values at a given pedal position, the truck will command a down shift? Just making sure I have the logic correct before adjusting.

    '17 Whipple'd S550
    Too many other projects to list.....see my YouTube channel for more: https://www.youtube.com/channel/UCr7...-XfDG53sCh6tcw

  2. #2
    Tuner TunedByNishan's Avatar
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    You pretty much have the idea down pat.

    Just multiply OSS RPM by That driven gear ratio and you will get Engine RPM.

    So, for 1->2 an OSS shift point of 1,350.00 is (1,350.00 X 4.17) = 5629 RPM

    2->3, an OSS shift point of 2,440 is (2,440 X 2.34) = 5709 RPM

    While the pedal position axis may not make much sense (our brains are used to thinking from 0 to 100%) you can see the trend going on in the OEM mapping where it appears to be that pedal position rows from 12 to 14 are considered WOT so I would make your changes there and adjust the rest as needed.
    www.tunedbynishan.com
    2018 Mustang GT - 10R80

  3. #3
    Advanced Tuner 96gt4.6's Avatar
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    Thank you very much!!!
    '17 Whipple'd S550
    Too many other projects to list.....see my YouTube channel for more: https://www.youtube.com/channel/UCr7...-XfDG53sCh6tcw

  4. #4
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    I would also convert oss to mph. That way you can still get low rpm shift points when the TC is slipping.
    "We can never be right, we can only be sure that we are wrong"- feynman

  5. #5
    Are the down shifts calculated on the gear you are leaving? Would the 2->1 oss be based on 2nd gear since that is the gear you are currently in?

  6. #6
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    Quote Originally Posted by Kcc0521 View Post
    Are the down shifts calculated on the gear you are leaving? Would the 2->1 oss be based on 2nd gear since that is the gear you are currently in?
    Upshifts and down shifts are calculated from OSS. Converting to MPH, just makes these tables make a bit more sense in your head, compared to OSS. OSS doesnt change with a gear change just like MPH doesnt, the engine RPM is what changes to keep every thing rev matched.

    Converting to RPM lets you see if you are potentially short shifting or over revving the engine. You should also be able to determine if some thing is slipping, and how much, if its out side your calculated numbers.
    "We can never be right, we can only be sure that we are wrong"- feynman

  7. #7
    I guess I phrased the question poorly. Do you use the 2nd gear or 1st gear ratio when converting the 2>1 downshift OSS speed to RPM. I assume you use the 2nd gear ratio since that is the gear it is in when the shift is commanded by the table.

  8. #8
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    Always the lower gear, if you are worried about the RPM maximum on shifts and higher gear if you are worried about lugging the engine on down shifts.