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Thread: Hellcat , ZF8, How to get Target shift points

  1. #1
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    Hellcat , ZF8, How to get Target shift points

    Coming from GM, I've done a fair share of mopar stuff.. But the new ZF8's i haven't had alot of time to play with until lately.

    Bought my wife a 16' Hellcat, got some goodies to go on it, but i wanna just tune it first. I understand all the tuning side, but I'm having a hard time figuring out how to raise or lower shift point / shift rpm. Does anyone have a link or care to explain this?

  2. #2
    Senior Tuner
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    Did you figure it out? Just have a lot if tables go change really. They over complicate it

  3. #3
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    The tables are based on output shaft speed so you need to multiple by the gear ratio.

  4. #4
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    Quote Originally Posted by ddtech View Post
    Coming from GM, I've done a fair share of mopar stuff.. But the new ZF8's i haven't had alot of time to play with until lately.

    Bought my wife a 16' Hellcat, got some goodies to go on it, but i wanna just tune it first. I understand all the tuning side, but I'm having a hard time figuring out how to raise or lower shift point / shift rpm. Does anyone have a link or care to explain this?
    Derek, shoot me an email. I would be glad to assist you with this.
    Specializing in building and tuning 1000hp, daily driven, 9 second cars!

    www.ostdyno.com Shop Phone: 724-368-9000

  5. #5
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    I also sent you a email mike

  6. #6
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    Quote Originally Posted by Flipfloptrader View Post
    The tables are based on output shaft speed so you need to multiple by the gear ratio.
    what were looking to do is add 5% ( x 1.05 ) to an entire output shaft speed table for a given aggression number and trans setting, that will raise ALL the shifts 5%, or make changes to individual cells using the math ( OSS x GR ) Am I on the right track here?

  7. #7
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    Yes. You can make an easy Excel sheet to make a copy and paste table. Multiply OSS value by gear ratio to find commanded shift point. If you have a desired shift point in mind, simply divide by gear ratio to find OSS value to input.

    Note that trans will always shift past commanded shift value. Important to log trans to see how far your trans overshoots given gear on average, that way you know what to command.

  8. #8
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    hi friends does any one have the stock 2015 zf8 hellcat file ? i have some issues at ver low throttle first to second shift , is slip a lot and need to compere with stock file that dont have it

  9. #9
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    Quote Originally Posted by toxicperformance View Post
    hi friends does any one have the stock 2015 zf8 hellcat file ? i have some issues at ver low throttle first to second shift , is slip a lot and need to compere with stock file that dont have it

  10. #10
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    Do you have to change a multitude of tables or just that one table for the upshift? Also I noticed the 7000 rpm table had numbers that are higher than the 6000 rpm table. Can I make the 7000 rpm table exactly the same as the 6000 rpm shift which has the 1.05 multiplier in there? Thanks

  11. #11
    Quote Originally Posted by AlphaCat View Post
    Do you have to change a multitude of tables or just that one table for the upshift? Also I noticed the 7000 rpm table had numbers that are higher than the 6000 rpm table. Can I make the 7000 rpm table exactly the same as the 6000 rpm shift which has the 1.05 multiplier in there? Thanks
    The trans could be using any one of 12-15 different shift tables depending what Mode you choose and Aggression level.

    I like to leave "Normal" mode shift tables alone and just up the shift RPM on the "Sport" mode tables.

  12. #12
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    But do not copy the main tables values into the other tables. Multiply the other tables by the same percentage as the maximum rpm speed. Correct? ie 1.0475 I used on the main maximum engine speed. Then go to the shift tables and aggression tables and multiply by 1.0475?
    Thanks

  13. #13
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    Log shift ID
    Focus on one table
    The tables that are active with the paddles are the best ones to work with when starting out to figure out what you're doing because they won't change based on aggression.

    Log OSS, turbine speed and engine rpm. Notice that depending on what the converter clutch is doing there may a difference in the spread between OSS and Engine RPM.

  14. #14
    Quote Originally Posted by spoolboy View Post
    The tables that are active with the paddles are the best ones to work with when starting out to figure out what you're doing because they won't change based on aggression.
    Great idea.
    Paddles and manual shift is usually 27 & 28.

    Disabling Aggression or rendering it neutral can help too.

  15. #15
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    Quote Originally Posted by duster360 View Post

    Disabling Aggression or rendering it neutral can help too.
    How do you do that?
    If in doubt, multiply everything by 1.1.

  16. #16
    Quote Originally Posted by spoolboy View Post
    How do you do that?
    By changing the Aggression mapping (Upper = Lower)or (more tedious)making all the maps under each aggression the same.