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Thread: Wierd power drop over 5800 rpm

  1. #1

    Wierd power drop over 5800 rpm

    Hey guys.
    For some reason i have been unable to figure it out why my power drops in a weird shape over 5800 rpm on ZL1 LSA camaro. Is not boost or any ignition source. I have tried raising torque management tables with no changes so far. Fuel is very stable and we dont have VTC so i dont know what else cuold it be.
    Here is the dyno chart, log and tune.
    Thanks alot.
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  2. #2
    It looks to me like you have a restriction somewhere that is limiting air/exhaust flow. If you notice that in the first run your power seems to peak later.
    Owner/Tuner@Evolution Automotive Performance
    Lincoln, Ne

  3. #3
    Quote Originally Posted by Evo8john View Post
    It looks to me like you have a restriction somewhere that is limiting air/exhaust flow. If you notice that in the first run your power seems to peak later.
    I was thinking the same, but now it has long tube with 3 inch colector, JLT Cai and 3 inch exhaust. OEM TB.......dont know.

  4. #4
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    I see the power drop on the dyno sheet but not in the log you posted. Maybe tire slip on the chassis dyno? With 27* of ignition advance at 1.22 g/cyl and no KR, you must be running some good gas!

  5. #5
    Senior Tuner TheMechanic's Avatar
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    Can't really get into checking right now but look at your gear/tire/trans ratio compared to dyno speed and you should see/not see a difference in mph at slip point.

  6. #6
    Senior Tuner 10_SS's Avatar
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    Quote Originally Posted by pannetron View Post
    I see the power drop on the dyno sheet but not in the log you posted. Maybe tire slip on the chassis dyno? With 27* of ignition advance at 1.22 g/cyl and no KR, you must be running some good gas!
    If you take a piece of paper and line it up to RPM and Speed on the log, you will see it changes at 5800rpm, matches up with the change in torque reported from the dyno.
    2010 Camaro LS3 (E38 ECU - Spark only). MS3X running complete RTT fuel control (wideband).
    Whipple 2.9L, 3.875" Pulley, kit injectors, supplied MSD Boost-A-Pump, stock pump
    LG Motorsports 1 7/8" Headers - No Cats, stock mid pipe with JBA Axle Back
    ZL1 Wheels/Tires

  7. #7
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    I looked more closely and I do see a small dip in the MAF reading starting at 5775 RPM.

  8. #8
    Senior Tuner 10_SS's Avatar
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    Quote Originally Posted by pannetron View Post
    I looked more closely and I do see a small dip in the MAF reading starting at 5775 RPM.
    I use the paper edge trick all the time, even at work, or anything with a plot line. People look at me funny, but it works!
    2010 Camaro LS3 (E38 ECU - Spark only). MS3X running complete RTT fuel control (wideband).
    Whipple 2.9L, 3.875" Pulley, kit injectors, supplied MSD Boost-A-Pump, stock pump
    LG Motorsports 1 7/8" Headers - No Cats, stock mid pipe with JBA Axle Back
    ZL1 Wheels/Tires

  9. #9
    97 oct and meth kit.

  10. #10
    Ok...will do. Thanks.