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Thread: Turbo Silverado L83 Torque Management Issue

  1. #1
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    Turbo Silverado L83 Torque Management Issue

    Stock L83 with rear mount turbo, 3psi running on meth having TM issues that I cant seem to improve. Running in speed density only, fueling is close. Ive bumped up peak torque 10% each dyno run and it seemed to help a little bit but now im not getting anywhere with it. Increased Driver Demand tables with no luck and increased Torque Tables with no change. TM is consistently kicking in the 5800 rpm and also in the 3500-3800 rpm range. First gen5 ive done so not very familiar with them, ive done a lot of reading and research on them about dealing with the TM but they are not working for me here on this one.

    Thanks
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  2. #2
    Tuning Addict 5FDP's Avatar
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    Yeah, return your peak torque table to basically stock plus a little. You aren't making 1,100 ft lbs of torque.

    Your rpm in gear cut off is 5,800rpm. Maybe change that.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

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    I missed that table, that would probably help. I was looking at the peak torque numbers in the log and was seeing in some ranges as much as 880ft lbs so I was trying to match the peak torque table with the number in the scanner and last dash effort I just added 20% into it to see if that table was my problem but had no luck. Would you have any suggestions in that 3500-3800rpm range? I see its only pulling timing and not shutting throttle blade in that area. I wish I knew what to log or what to look for when it comes to the torque management. I think is it Immediate Engine Torque controlling Spark and Predicted Engine Torque controlling the throttle body? Thanks 5FDP for taking a look!
    Last edited by mxdirtking; 09-16-2021 at 05:52 AM.

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    So looking over the logs more and doing more research I have discovered that in every single log at exactly 100kpa TM kicks in pulls timing to zero and then comes back in at 104-105kpa, it?s consistently doing this.

    So when the truck first sees boost TM kicks in and it pulls timing. So possibly is there like a transition to boost or a table referencing kpa vs torque or something to that extent, I can?t find anything.

    All the help is much appreciated. Thank you

  5. #5
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    Reduce your Virtual Torque tables in the WOT ranges.
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    Will do, thanks. Even completely stock VT tables this issue was happening. I will set it all back to stock.

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    Still no luck tonight.

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    Update:

    I have Immediate Engine Torque Source logged and during the TM issue at 3200-3600 range it?s telling me it?s coming from ?Trans S?.

    Is this an issue with the TCC slipping to much and pulling timing? I have TCC slip logged but can?t get it to record with this truck. Same with trying to log Current Gear.

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    Okay found out Trans S = Transmission Short term TQ mgt.

    Reading that this is resolved by changing the Minimum Spark Base table in the WOT areas to 0 up to 6 degrees.

  10. #10
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    The Minimum Spark Base table is the floor for Torque Management to reduce timing to remove torque. You might be able to limit the amount of timing that TMA can pull in that range this way. If it works and drives good then I suppose its fine. The correct way to do it is to tell the ECU that it isn't making as much torque as it thinks it is when you're getting TMA kicking in at boost onset.
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    Senior Tuner Mep_q8's Avatar
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    Just had a quick glance, looks like it may be downshifting? Can you log Gear Position. If you have access to edit your TCM files, look into tip in Trq Mgmt too.

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    Quote Originally Posted by TriPinTaZ View Post
    The correct way to do it is to tell the ECU that it isn't making as much torque as it thinks it is when you're getting TMA kicking in at boost onset.
    Are you referring to the Virtual Torque Tables and reducing torque to tell the ECU that it isn?t making as much torque in that area?

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    Quote Originally Posted by Mep_q8 View Post
    Just had a quick glance, looks like it may be downshifting? Can you log Gear Position. If you have access to edit your TCM files, look into tip in Trq Mgmt too.
    It stays in 4th throughout the entire pull but I think I have found out my issue at the 5800rpm area, I found out that the WOT Shift RPM is set at 5900rpm and it?s just hitting that limiter and not the 6500rpm rev limiter.

    I?ve tried to log Current Gear but can?t get it to show up on this truck for some reason.

    I?ll look into that Tip in TM on trans side also.


    Thanks

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    Update:

    I set Minimum Spark Base table to zero in the WOT areas and it took care of my TM problem. Now I?ll just have to see how the drivability is now with this change.

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    Technically that would mean the ECU still has the ability to use TMA to reduce the spark advance to 0 degrees in that area.
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    Quote Originally Posted by TriPinTaZ View Post
    Technically that would mean the ECU still has the ability to use TMA to reduce the spark advance to 0 degrees in that area.
    That makes sense, but TM is completely gone in that area now and is following spark table. It doesnt really make any sense because yes you would think TM would kick in and reduce spark to 0 but its not.


    If there is another way to do it i'm all for learning anything about these 5th gens.

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    Quote Originally Posted by mxdirtking View Post
    That makes sense, but TM is completely gone in that area now and is following spark table. It doesnt really make any sense because yes you would think TM would kick in and reduce spark to 0 but its not.


    If there is another way to do it i'm all for learning anything about these 5th gens.
    If that is the only thing you changed and it works, then heck it works lol. I'm not here to say anyone is wrong. As much as we know about the Gen V's there are still quite a few mysteries with them.
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    Quote Originally Posted by mxdirtking View Post
    Update:

    I set Minimum Spark Base table to zero in the WOT areas and it took care of my TM problem. Now I?ll just have to see how the drivability is now with this change.
    Bring this back to life...

    I have been plagued with TMA at 5,900 RPMs for ever and I am going to give this a try to see how it reacts. Every time I hit 5,900 RPMs at .66g, it pull timing for about .2 seconds then goes back to normal all the way to shift @ 6,500.

  19. #19
    Senior Tuner Ben Charles's Avatar
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    Hitting .66 at 5900rpms with boost is a problem

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  20. #20
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    Quote Originally Posted by Ben Charles View Post
    Hitting .66 at 5900rpms with boost is a problem
    This does not have boost, N/A head, cam, ported intake...