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Thread: 6L80E Tq man advance after shift

  1. #1
    Tuner in Training
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    Aug 2017
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    6L80E Tq man advance after shift

    Can someone tell me how I can get rid of this tq man right after the shift? It lingers for a bit then I get my full timing. @ 1:14 and 1:17 WOT 2-3 and 3-4 shift as an example. Shift feels good, but there is tq man advance after the shift. Log and tune attached. Thanks in advance.

    10 - 7 tune.hpt
    tq man after shift.hpl
    Last edited by gxp1; 10-08-2020 at 05:09 PM.
    2007 Solstice GXP - L83/6L80E - [email protected]

  2. #2
    Tuner
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    Quote Originally Posted by gxp1 View Post
    Can someone tell me how I can get rid of this tq man right after the shift? It lingers for a bit then I get my full timing. @ 1:14 and 1:17 WOT 2-3 and 3-4 shift as an example. Shift feels good, but there is tq man advance after the shift. Log and tune attached. Thanks in advance.

    10 - 7 tune.hpt
    tq man after shift.hpl
    I had a similar issue but throttle closing. In your log you can see trans as the torque source during the timing pull. Guess it is either slip related or some torque value is exceeded. Log trans slip rpm and see if you have some slip, in that case you can increase oncoming clutch pressure and it may go away. If not some torque limit is probably exceeded. Yet I have not figured out the exact cause to why it shows up after shifts (basically as long as the oncoming clutch is active or slip is present) but I had luck lowering the MBT timing tables where needed to change the reported engine torque. I find it easier than messing with the virtual torque tables.

  3. #3
    Tuner
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    Apr 2014
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    The computer doesn't like it when engine torque exceeds predicted torque, because that means the engine is not controlling the airflow properly. You can also see the airflow problem by comparing throttle desired airmass vs. cylinder airmass. Cylinder airmass is always higher because the turbo is forcing the air through. The throttle blade airflow equations assume there is always barometric pressure on the front of the throttle blade, but with a turbo that is not the case, so more air moves past the throttle blade than the computer is expecting.
    It looks like there are a lot more bad shifts in this log.. 1:51, 1:54, 4:58, 5:00, 6:15.. all caused by the same problem.

    Looks like your BARO is stable, so you must have done the breakout, which helps the VVE, but still doesn't control the throttle properly.

    I fixed this by changing the Map config to TC-MAP-TIAP-BARO.
    Here is a link to my writeup. https://forum.hptuners.com/showthrea...l=1#post585966

    The driving and shifting is wayyyy better with this setup. I think it is a critical step when turbo charging any GenV ECU car.


    Also, looks like you need to raise your peak torque from about 4800 rpm through 6500 rpm. Your WOT shifts would probably be fine if you just increased that.

    Good luck!
    2014 Silverado L83 | Knockoff S369 Turbo | LT1 Fuel Pump and Injectors | MAST L84 Port Intake | MS3Pro Secondary Fuel Computer