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Thread: shift points

  1. #41
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    Quote Originally Posted by bb-tt View Post
    Ok

    So i am tripped up now, so after reviewing logs in sport mode i have seen TCC map 3, 8, & 13 used in sport mode and 27, 40, & 47 used in Manual mode. so if i look at the TCC apply/release speed maps

    tcc map 3 uses 1-8
    8, 13 use 11-18

    and 27, 40, 47 use 31-38

    But when i look at TCC A/R speed map 31 it is set to 10,000 rpm???? WTF i look at log and see [ttc pattern 27], [tcc mode 31] what am i missing?






    That is indeed really strange. I checked my maps, and it looks like I have the same maps as you:
    tcc map 3 uses 1-8
    8, 13 use 11-18
    and 27, 40, 47 use 31-38

    However, my TCC table looks a lot more like you'd expect for maps 31-40... (Every other table looks identical to yours)
    TCC Tables.PNG

    I never changed mine, so these are the same as stock for me. Does the 10,000rpm also show up in your stock maps? I wonder if you may have accidentally changed them or something. If not, that is certainly weird.

  2. #42
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    Quote Originally Posted by Hemithis01 View Post
    When you launch from a stop you are technically in 0 gear. Not 1st. So make sure your tq request maps allow you build more tq off the line. Then raise your stall table and you should be able to launch in a higher rpm
    By "tq request maps", do you mean this table?
    tq request map.PNG

    If so, I already set N to 800. If I wanted a stall speed of 950, would I also have to set this to 950?

  3. #43
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    Quote Originally Posted by Woodepic View Post
    That is indeed really strange. I checked my maps, and it looks like I have the same maps as you:
    tcc map 3 uses 1-8
    8, 13 use 11-18
    and 27, 40, 47 use 31-38

    However, my TCC table looks a lot more like you'd expect for maps 31-40... (Every other table looks identical to yours)
    TCC Tables.PNG

    I never changed mine, 2011 a4 8hp55 so these are the same as stock for me. Does the 10,000rpm also show up in your stock maps? I wonder if you may have accidentally changed them or something. If not, that is certainly weird.
    Yes just compared with stock there is no change there, but based on Hemi's comment think i was looking in wrong area anyway this just may be an issue for another time.

    So if i want to increase stall speed when brake boosting i should be looking at TCM 46856 Gear max torque limit and increasing N not 1 and tcm 46957 gear max torque limit stall and increase that or just go max torque limit slip and increase that?? i was thinking i needed to go to tcm 46968 and increase 31 unlock>slip and Slip>lock but it would appear i was chasing rabbits.

  4. #44
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    Quote Originally Posted by bb-tt View Post
    So if i want to increase stall speed when brake boosting i should be looking at TCM 46856 Gear max torque limit and increasing N not 1 and tcm 46957 gear max torque limit stall and increase that or just go max torque limit slip and increase that?? i was thinking i needed to go to tcm 46968 and increase 31 unlock>slip and Slip>lock but it would appear i was chasing rabbits.
    I'm not sure that slip is what we want to happen. Here's a quote from Steven about the TCC modes:
    Quote Originally Posted by Steven@HPTuners View Post
    The converter clutch operates in one of 4 distinct modes. Open, Slip, Lock, and Overlock.

    Open: No engagement of the clutch at all.
    Slip: The clutch is engaged with a specific controlled slip RPM. I.e. 25RPM difference between turbine speed and input shaft speed.
    Lock: The clutch is engaged in an attempt to fully lock turbine speed and input shaft speed.
    Overlock: The clutch is completely engaged, i.e. converter clutch pressure is maximized.
    Wouldn't we not want to be slipping the clutch on the launch? Ideally we'd have the TCC clutch open, and we're just relying on the torque converter. If we were spinning the clutch, we'd probably damage it rather quickly. I suppose it depends on what OSS the TCC starts to slip. I'll look at some maps.

    Edit: Looks like in 1st gear on shift pattern 8 (used for amax) at 60+% throttle, the TCC is unlocked all the way until 850 OSS, aka 4000rpm in 1st... Although I'm not sure the values in [TCM] 46967 are even OSS...If they are, it's rather irrelevant for launching as the OSS is ~0 until we start moving. Are we able to log TCC state in VCM scanner?
    Last edited by Woodepic; 1 Week Ago at 04:28 PM.

  5. #45
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    Quote Originally Posted by Woodepic View Post
    I'm not sure that slip is what we want to happen. Here's a quote from Steven about the TCC modes:


    Wouldn't we not want to be slipping the clutch on the launch? Ideally we'd have the TCC clutch open, and we're just relying on the torque converter. If we were spinning the clutch, we'd probably damage it rather quickly. I suppose it depends on what OSS the TCC starts to slip. I'll look at some maps.
    Ideally we would have tcm(s) loaded that the hellcat or demon has so we could program a transmission brake. But we are stuck brake boosting, but yes i think i was looking at it wrong.

  6. #46
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    we launch with an open clutch. slip is just an intermediate phase between open and locked for smoothness. my duramax has a triple disk converter and the first time I drove it I thought something broke. it hits hard when it locks.

    trans brake helps with not pushing through the brakes. it does that by engaging 2 gears at the same time and they fight against each other. the bad thing is you're not preloading the drivetrain. so for axle/diff reliability a brake launch is better. if you're pushing through the brakes add an electric vacuum pump from a b5/c5/mkiv

  7. #47
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    Quote Originally Posted by ed1380 View Post
    Hey... am I the only one who finds the aggression-based shift point scheduling in these transmissions annoying? In general I think the ZF8 is a great transmission, but sometimes I get the feeling the transmission is trying to guess and adjust to what I want, and I'm trying to guess and adjust to what it's going to do, and we just keep going around in circles.

    I'm curious if anyone's ever tried going into the "shift pattern aggression mapping" table and setting the values all the same for each mode. For example in the table above, plug the same number into lower aggression and upper aggression for driver types 0-5, and another number for types 6-10. That way in each mode (by "mode" I mean regular, sport, etc.) it would always use the same set of tables, only varying by acceleration value. It seems to me that would make the transmission's operation more predictable, and reduce the number of tables you need to adjust when tuning.

  8. #48
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    Quote Originally Posted by ed1380 View Post
    we launch with an open clutch. slip is just an intermediate phase between open and locked for smoothness. my duramax has a triple disk converter and the first time I drove it I thought something broke. it hits hard when it locks.

    trans brake helps with not pushing through the brakes. it does that by engaging 2 gears at the same time and they fight against each other. the bad thing is you're not preloading the drivetrain. so for axle/diff reliability a brake launch is better. if you're pushing through the brakes add an electric vacuum pump from a b5/c5/mkiv
    Hmm i guess i wasn't thinking about the abuse on the drive line, was just thinking you could get a quicker launch by letting go of a shift lever rather then releasing the brake pedal.

  9. #49
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    Yeah... and it might be extra-abusive on an AWD drivetrain like in our Audis, because those drivetrains can have a lot more "slop" than 2WD cars due to the larger number of diffs, CV joints, etc.

  10. #50
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    Quote Originally Posted by ELaw View Post
    Hey... am I the only one who finds the aggression-based shift point scheduling in these transmissions annoying? In general I think the ZF8 is a great transmission, but sometimes I get the feeling the transmission is trying to guess and adjust to what I want, and I'm trying to guess and adjust to what it's going to do, and we just keep going around in circles.

    I'm curious if anyone's ever tried going into the "shift pattern aggression mapping" table and setting the values all the same for each mode. For example in the table above, plug the same number into lower aggression and upper aggression for driver types 0-5, and another number for types 6-10. That way in each mode (by "mode" I mean regular, sport, etc.) it would always use the same set of tables, only varying by acceleration value. It seems to me that would make the transmission's operation more predictable, and reduce the number of tables you need to adjust when tuning.
    make all the maps in aggression 1, 2 the same for drive and 3, 4 for sport