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Thread: I want a nice crisp rev that barks not howwwwwwwwls.

  1. #1
    Tuner in Training
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    I want a nice crisp rev that barks not howwwwwwwwls.

    I know this is going to sound obnoxious but I want my 2016 silverado to just rev and settle not haaaannnnngggg.
    I had issues with this while wheeling too. I get stuck, try to go back and forth but the RPMS hang so I cant bang between R and D without fear of busting a U joint....
    But ... to be honest I'd just be happy if I could stomp the pedal, get the throttle to open up all the way quick and close all the way when I want it to. That kind of control would make a TON of difference crawling and doing technical stuff....

    But let's start simple.

    How do I get my throttle to open as fast as possible,
    BUT MORE IMPORTANTLY CLOSED as fast as possible?

    Here's a log. Run Pedal Position vs Throttle position on the chart ... throw in in RPM and spark if you want but ... that's not my hangup it's the throttle position
    It's 6 seconds (ish) of a light rev tap and a heavier rev. You can see the throttle hangs open at around 20% ... booooo.
    I can not find in the software how to fix that
    (Remember this is a Gen V so none of that dashpot, follower, cracker and cheese stuff)

    Can I get some help from you fine folks, I'd really appreciate it.
    98608H2 _rev.hpl98608H2_121217_SpkKR.hpt

  2. #2
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    I found out in park the overrev PID sees the "potential" to jump past the 4,000 RPM limit and will close the throttle WAY before 4,000 RPM.
    (just found out I didn't save that log ... crap ... )
    I would assume it would be the same in gear (in something like LOW range where a quick rpm spike is possible), but that is a theory until I log a move like that.
    Some things I would like to know
    -Why does the throttle opening flatten a little then ramp more slowly when PE kicks in?
    and How on earth do I get the motor back to idle quicker? It hangs like CRAZY

  3. #3
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    I got the quick GO I was looking for by modifying the DD tables
    I used the calculated VSS and and set it based on a more linear profile.
    I tried a 0 to 328 linear approach ... and it was too much.
    So I eased up, used an increasing profile (just a little bit) and really like the feel.

    As far as getting back to idle quickly ... I tried modifying the adaptive idle controls and it really taught me a-lot!
    It taught me that I don't know what I'm doing, and the guys from the factory are in fact much smarter than I.
    ... I was fairly sure it wouldn't affect anything above 1,300 RPM ... it didn't.

  4. #4
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    check for iac settings if Rolling RPM / MAP,RPM or Rollback VSS is unable to change that.
    I have a burrito in my colon, yet refried beans come out...
    How i know it's from the same meal? I didn't ingest corn any other time.

  5. #5
    Senior Tuner Higgs Boson's Avatar
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    Quote Originally Posted by * _ * View Post
    check for iac settings if Rolling RPM / MAP,RPM or Rollback VSS is unable to change that.
    welcome to GenV torque based controllerland.

  6. #6
    Anyone figure something out on this yet? Throttle seems so lazy on close, it just doesn't make sense why it would take so long to shed RPMs.

  7. #7
    Advanced Tuner IARLLC's Avatar
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    Fast torque exit makes the requested torque continue and smoothly trail off long after you let off the gas. I have messed with it a little to keep some GEN5 desert race trucks from flinging themselves headlong over cliffs....but I did not have enough time to really get the quick drop I would prefer. Drivers were happy....survived so far...I am really interested if somebody can give some good advice on this. I will be happy to apply it too.

  8. #8
    Senior Tuner Higgs Boson's Avatar
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    log your throttle blade, does it mimic the engine RPM rise and fall?

    install a lightweight flywheel and clutch, the stock one weights 100000 pounds.....intertia/momentum.

  9. #9
    Quote Originally Posted by Higgs Boson View Post
    log your throttle blade, does it mimic the engine RPM rise and fall?

    install a lightweight flywheel and clutch, the stock one weights 100000 pounds.....intertia/momentum.

    I will have to check it, HB. I just don't remember my C6 taking so long to dump revs, both A6 so I know there is still some inertia to shed but it seems like the FBW throttle doesn't have the ability to snap shut.

  10. #10
    Quote Originally Posted by IARLLC View Post
    Fast torque exit makes the requested torque continue and smoothly trail off long after you let off the gas. I have messed with it a little to keep some GEN5 desert race trucks from flinging themselves headlong over cliffs....but I did not have enough time to really get the quick drop I would prefer. Drivers were happy....survived so far...I am really interested if somebody can give some good advice on this. I will be happy to apply it too.
    I was looking at those settings the other day, you just raising the enable delta?

  11. #11
    Advanced Tuner IARLLC's Avatar
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    Yes. I wish that there had been time to refine this issue. I ended up setting them at about 6,000 for enable and 4,000 for disable. The main point was to get it to quit accelerating when you let off the gas. They were happy so I guess it worked. I did not have a chance to really run them before that race but there is another coming up and this time we will have quite a lot more time for refinement. From revving one of them in my shop the other day....I would still like to improve how quickly they respond to letting off the gas if I can find out how.

  12. #12
    Quote Originally Posted by IARLLC View Post
    Yes. I wish that there had been time to refine this issue. I ended up setting them at about 6,000 for enable and 4,000 for disable. The main point was to get it to quit accelerating when you let off the gas. They were happy so I guess it worked. I did not have a chance to really run them before that race but there is another coming up and this time we will have quite a lot more time for refinement. From revving one of them in my shop the other day....I would still like to improve how quickly they respond to letting off the gas if I can find out how.
    You play with the pressure control any under "Engine, Airflow, Pressure Control"?

  13. #13
    Advanced Tuner IARLLC's Avatar
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    Not yet. I saw that they suggest 20-40kpa to improve responsiveness but....in the sand, side-hills, rocks.... I really want smooth progression. I want a predictable response as well though.... so maybe I will give those a try. I am just finishing up some suspension stuff on one of them so next week I might get to try out some pressure control changes.

    Have you seen that pressure pressure drop changes improve response to letting off the throttle as much as giving it some?

  14. #14
    Quote Originally Posted by IARLLC View Post
    Not yet. I saw that they suggest 20-40kpa to improve responsiveness but....in the sand, side-hills, rocks.... I really want smooth progression. I want a predictable response as well though.... so maybe I will give those a try. I am just finishing up some suspension stuff on one of them so next week I might get to try out some pressure control changes.

    Have you seen that pressure pressure drop changes improve response to letting off the throttle as much as giving it some?
    I haven't messed with it either, I am laid up with a broken ankle and cleaning up some of the tuning on my truck but will give it a shot a soon as I can and report back. I think it is a newer parameter as I don't remember seeing it last time I was tuning.

  15. #15
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    Too much spark advance was causing my throttle to hang in this area. Not sure but it might help.
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