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Thread: Drag racing converter slip issue

  1. #1

    Drag racing converter slip issue

    I'm seeing some strange behaviour with my car when launching at the drag strip, the converter slips and starts to lock up but when the engine gets to about 5000RPM the converter slip increases briefly before begining to lock up again. I have discussed this with the converter manufacturer any they are blaming the tune but I cant figure out what in the trans tune would cause this.
    You can see what I'm taking about in the red converter slip trace in the image taken from the attached log.
    Car specs are in my sig.

    Has anyone seen this before? if so what was the cause?
    GXP62L Tune 5.002 drags 28 tyres no TC lifted shift points.hpt
    run 2 11.30 at 121.hpl
    Converter slip.png
    2010 GXP Maloo ute, LS3, 6L80E.
    MM heads, 240/252@50 solid cam, 12.75:1 compression, 4500 Dominator converter, 3.46 rears.
    Shooting for 10s eventually.

  2. #2
    Senior Tuner Lakegoat's Avatar
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    According to your converter lockup table, you are not locking the converter in gears 1thru 4 at wot.
    2000 Camaro SS 2015 L83 port injected, Whipple 3.0, 4L80E, 8.8 Ford
    2013 Silverado 5.3, 6L80k 8.8

  3. #3
    I didnt word that well did I, i was refering to the coverter itself, not to the converter lock up clutch. I realise the converter does actually lock up as such but the slip shouldn't decrease then increase then decrease again, at leasted it didn't with the stock converter and no other logs I could find show this behaviour.
    2010 GXP Maloo ute, LS3, 6L80E.
    MM heads, 240/252@50 solid cam, 12.75:1 compression, 4500 Dominator converter, 3.46 rears.
    Shooting for 10s eventually.

  4. #4
    I did a little reading on your trans maybe it's not your tune. There are a few things about that trans that may make it undesirable for drag racing in it's stock form. Have you had anything done to the trans itself or just the convertor. It was made for heavy cars or trucks 8000 to 14000 lbs but I couldn't find anything about drag racing. I'm not saying it won't work I just think you should check it out.

  5. #5
    Advanced Tuner
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    CHECK YOUR TRANS FLUID LEVEL. Sound like low fluid symptoms. I assume 6L80? I can take a look at your logs later this evening. I have a G8 and I have seen a few people have this exact issue...
    Daily Driver= 2003 BMW 330xi
    Weekend Cruiser= 2009 Pontiac G8 GT (Vararam, TSP LS3 N/A Stage 1, OBX, CTS-V converter, MagnaFlows w/ J-Pipes, 160 t-stat)
    Project Car= 1991 Chevrolet Camaro RS (LQ4 w/ Gen 4 Rods, LS3 heads, turbo...)
    Truck= 2007 Chevy Silverado 1500 LT LY5 4x4

  6. #6
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    Make sure it's at least a quart over.

  7. #7
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    Quote Originally Posted by sevinn View Post
    Make sure it's at least a quart over.
    ^^^What he said OR get a Camaro pan and never worry about it again...
    Daily Driver= 2003 BMW 330xi
    Weekend Cruiser= 2009 Pontiac G8 GT (Vararam, TSP LS3 N/A Stage 1, OBX, CTS-V converter, MagnaFlows w/ J-Pipes, 160 t-stat)
    Project Car= 1991 Chevrolet Camaro RS (LQ4 w/ Gen 4 Rods, LS3 heads, turbo...)
    Truck= 2007 Chevy Silverado 1500 LT LY5 4x4

  8. #8
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    Quote Originally Posted by jaydubb71 View Post
    ^^^What he said OR get a Camaro pan and never worry about it again...
    Do both! lol

  9. #9
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    Quote Originally Posted by sevinn View Post
    do both! Lol
    ^^^truth!
    Daily Driver= 2003 BMW 330xi
    Weekend Cruiser= 2009 Pontiac G8 GT (Vararam, TSP LS3 N/A Stage 1, OBX, CTS-V converter, MagnaFlows w/ J-Pipes, 160 t-stat)
    Project Car= 1991 Chevrolet Camaro RS (LQ4 w/ Gen 4 Rods, LS3 heads, turbo...)
    Truck= 2007 Chevy Silverado 1500 LT LY5 4x4

  10. #10
    I had wondered about fluid level but it already has a deep pan and the level was checked before taking it to the track, I though the fluid issue was more around poor shifting. None the less I will try adding some more fluid and see if that helps.
    2010 GXP Maloo ute, LS3, 6L80E.
    MM heads, 240/252@50 solid cam, 12.75:1 compression, 4500 Dominator converter, 3.46 rears.
    Shooting for 10s eventually.

  11. #11
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    Low fluid will definitely tank converter efficiency.

  12. #12
    You guys nailed it, overfilled the trans by a litre and the problem was gone. I guess the deep pan wasn't enough by itself.

    Thanks jaydubb71 and sevinn for your help.
    2010 GXP Maloo ute, LS3, 6L80E.
    MM heads, 240/252@50 solid cam, 12.75:1 compression, 4500 Dominator converter, 3.46 rears.
    Shooting for 10s eventually.

  13. #13
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    Quote Originally Posted by Xjas View Post
    You guys nailed it, overfilled the trans by a litre and the problem was gone. I guess the deep pan wasn't enough by itself.

    Thanks jaydubb71 and sevinn for your help.
    You're welcome. Always glad to help.
    Daily Driver= 2003 BMW 330xi
    Weekend Cruiser= 2009 Pontiac G8 GT (Vararam, TSP LS3 N/A Stage 1, OBX, CTS-V converter, MagnaFlows w/ J-Pipes, 160 t-stat)
    Project Car= 1991 Chevrolet Camaro RS (LQ4 w/ Gen 4 Rods, LS3 heads, turbo...)
    Truck= 2007 Chevy Silverado 1500 LT LY5 4x4

  14. #14
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    That's great to hear!