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Thread: Transmission tune needs fresh eyes

  1. #1
    Tuner cp-the-nerd's Avatar
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    Transmission tune needs fresh eyes

    I have my redline increased to 7000 rpm and shift torque factor dropped to .500 across the board, neither of those changes had the desired effect. At 7000 it bounced on the new limiter instead of shifting and for the life of me, I couldn't feel any difference between shift torque factor of 1.00, .75, and now finally .5. I was hoping for crisper shifts, along with decreasing desired shift time from .3 sec to .2 sec.

    I'd appreciate if someone could look at my tune and give me pointers where I may have gone wrong.

    cp-the-nerd_09-Malibu-LY7_v2.0.hpt
    2017 Chevy SS 6.2L/6M

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    Tuner cp-the-nerd's Avatar
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    I forgot to mention, after I hit the rev limiter, I dropped the WOT shift speeds a few MPH but I haven't been able to test it yet. I had them set 3-4 mph below the actual 7000 rpm speed, but particularly in 1st gear, the speed builds fast and I was wondering if the computer couldn't keep up. The stock tune had 1st gear WOT shift speed set to 34 mph, but 1st went all the way to 42 mph @6800.

    At 7000 rpm, the car is going 43.5 mph and I had the shift point set to 40. Second gear went to 68 mph and I set WOT shift speed to 64 mph. Both hit the limiter, though 2nd gear bounced on the limiter and shifted like it was trying to catch up.
    2017 Chevy SS 6.2L/6M

  3. #3
    Tuner cp-the-nerd's Avatar
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    Well I ironed out the 7000 rpm redline shifts for the most part, and my new transmission table is WORLDS better than stock. I'm still lost on improving transmission shift time. I increased the inertia factor profile upshift and power downshift tables significantly and cut the desired shift time tables in half for base upshift, special, and power downshift, but it still feels delayed and not particularly crisp.

    Any help would really be appreciated, it's not easy learning this stuff from scratch based on searches and threads about other cars. The closest topics I've found are for the RWD 6L80 and a few about the Cruze (almost all of them were written by Chris from HPTuners).

    I logged some time in the car. Acceleration from 0-70 shows some KR in the midrange that I'd like to address. The little dip in the middle of the screenshot was a slight bounce on the limiter.



    Tune_V2.1_Scan.hpl

    cp-the-nerd_09-Malibu-LY7_v2.1.hpt
    2017 Chevy SS 6.2L/6M

  4. #4
    Senior Tuner Russ K's Avatar
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    Post your stock tune, and I'll see what you all changed.

    Russ Kemp

  5. #5
    Tuner cp-the-nerd's Avatar
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    Thanks! I really appreciate it.

    Since that last post, I've turned off torque management on upshifts and power downshifts and tweaked a few other things. Here's the stock tune and my latest tune.

    cp-the-nerd_09-Malibu-LY7_v2.3.hpt

    2009_Chevy_Malibu_LY7_Stock.hpt
    2017 Chevy SS 6.2L/6M

  6. #6
    Senior Tuner Russ K's Avatar
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    Try this trans tune. I reduced the upshift torque management by 50%. I never disable the upshift torque management on the A6 trans, as the shifts become too harsh. And I set the min spark advance during reduced power to 0* (stock is -15*).

    Does your car have a performance or sport mode for the trans? Or just a tap shift?

    If you want firmer shifts, just reduce the shift times by 5 or 10% at a time. If the shifts are too firm, then increase the shift times.

    Russ Kemp
    Attached Files Attached Files

  7. #7
    Tuner cp-the-nerd's Avatar
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    You're awesome. Thank you for taking the time to do all that. This car does not have a sport mode, just the "Manual Mode" in the slot past drive that uses the paddle shifters.

    You said you reduced upshift torque management by 50%, was that done with the shift pressure tables? I see those values are raised, so I would gather that the max pressure (290) is the equivalent of no tq. management?

    My other question is what effect ETC Tip-In Limiting actually does. I was going to change it, but I am determined to learn about any settings before I change them. I've done tons of research to get as far as I have, but there's limited resources for this particular drivetrain so I'm trying to understand your changes.
    2017 Chevy SS 6.2L/6M

  8. #8
    Senior Tuner Russ K's Avatar
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    Quote Originally Posted by cp-the-nerd View Post
    You said you reduced upshift torque management by 50%, was that done with the shift pressure tables? I see those values are raised, so I would gather that the max pressure (290) is the equivalent of no tq. management?.
    Look at the cold multiplier. The shift pressures are raised by 40 psi to firm the shifts, nothing to do with upshift torque management.

    Quote Originally Posted by cp-the-nerd View Post
    My other question is what effect ETC Tip-In Limiting actually does. I was going to change it, but I am determined to learn about any settings before I change them. I've done tons of research to get as far as I have, but there's limited resources for this particular drivetrain so I'm trying to understand your changes.
    ETC Tip-in is what limits the throttle opening when you do a quick light throttle stab.

    Russ Kemp

  9. #9
    Tuner cp-the-nerd's Avatar
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    Had a chance to test things out, wound up combining your tune with mine so I could keep my trans tables and a few other things I'd been ironing out over the past two weeks, but still use the performance and feel settings you added. I really like the way the shifts have turned out with the pressure changes and cold multiplier table with torque management back on.

    What exactly is the cold multiplier torque management? Is that controlling the TM between shifts or what?

    Your explanations are a great help for my learning process.
    2017 Chevy SS 6.2L/6M

  10. #10
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    Regarding the Cold Multiplier changes - wouldn't that only reduce the torque management when the transmission is cold (-40* -> 104*F)?

    If you wanted to reduce the torque management all of the time, would you use the "Shift Torque Factor" instead? Instead of 1.0 (full torque management), would you make it .5 to set torque management to 50%, for example?

    Also, regarding ETC Tip-in, I've noticed that it is disabled for 1st gear on my stock tune (2012 Impala, 3.6L LFX engine, 6T70 transmission) and one of the issues with the car is that you get a "clunk" sometimes when reapplying the throttle after coasting at low speeds (some call it "driveline lash") - would enabling ETC tip-in on 1st gear possibly help avoid that clunk? Any potential issues with enabling ETC tip-in on 1st gear?

    Thanks in advance!