Results 1 to 9 of 9

Thread: Cobra LS6 Swap Tuning, WOT dropping out

  1. 07-20-2011 #1
    Unreal
    Unreal is offline
    Tuner in Training
    Join Date
    Feb 2010
    Location
    SLC, UT
    Posts
    47

    Cobra LS6 Swap Tuning, WOT dropping out

    Friend of mine put a crate ls6 motor in a shelby cobra replica with a 4l65E tranny. We are trying to get it tuned. Chevy dealer put a 2004 automatic base tune in the ecu and then I copied over the stock 2004 z06 timing and VE maps since it is an ls6. Car drives great, idles good, shifts good. The problem we are seeing is at WOT the car downshifts goes like hell to ~5500rpm then feels like he let off the gas, coast for about 1/2-3/4 second then pulls up to 5500 again, and repeats that. TPS signal is at 100% the whole time but it feels like he is pedaling it on and off. Looking at the logs I took I don't see anything out of the ordinary. No KR, maf signal looks good, etc. Any ideas what this could be? Torque management? Some wierd automatic thing? I've never messed with automatics. We did calibrate the VSS so the speed is correct. What should I log to start narrowing it down?

    I'll post the tune file and logs tonight once I keep to my laptop. I'm at work. I would love to have someone look at them and see if there are other things to adjust with this swap. Since the ls6/4l65e were never together I had to piece together 2 maps so I might have missed something.
    Reply With Quote Reply With Quote
  2. 07-20-2011 #2
    Throttle
    Throttle is offline
    Advanced Tuner
    Join Date
    Apr 2006
    Location
    western NY
    Posts
    339
    fuel pressure?
    2000 Firebird,2002 O.S.,LQ4 370,Borg Warner S475,truck mani.,Eagle crank,Callies Compstar Rods,Wiseco-11 4.030 pistons 9.4:1 comp.,LS3CNC heads,LS3 intake,NW92mm throttle body,ID1000 injectors,BTR trunion upgrade,LJMS STG3 cam,LS7 Lifters,ARP Studs-bolts,Frozen Boost A to W intercooler,JGS 60MM BOV,2 40mmJGS Wastegates,4L80E trans wth segment swap,CircleD 3400 single disk,MOSER 12 3.31gears ,BMR K-Mem.,2 Walboro 450 pumps,Returnstyle fuelsystem MAGNAFUEL regulator.
    LS1Tech sig KRAZY K 2000 TA
    Reply With Quote Reply With Quote
  3. 07-20-2011 #3
    SargeZ06
    SargeZ06 is offline
    Advanced Tuner
    Join Date
    Jul 2008
    Location
    Louisville, KY
    Posts
    417
    Quote Originally Posted by Throttle View Post
    fuel pressure?
    That would make sense. LS6 injectors are rated at 58lbs. Don't think the stock Cobra pump is near that.
    Reply With Quote Reply With Quote
  4. 07-20-2011 #4
    Unreal
    Unreal is offline
    Tuner in Training
    Join Date
    Feb 2010
    Location
    SLC, UT
    Posts
    47
    Has a 255lph walbro pump in it. Seems to be in the tune or settings because it just shuts down at 5500 until it gets to ~3000 then revs again. No knock, no signs of losing fuel pressure. Gas tank was full so it shouldn't be from sloshing around.
    Reply With Quote Reply With Quote
  5. 07-20-2011 #5
    Throttle
    Throttle is offline
    Advanced Tuner
    Join Date
    Apr 2006
    Location
    western NY
    Posts
    339
    post tune please
    2000 Firebird,2002 O.S.,LQ4 370,Borg Warner S475,truck mani.,Eagle crank,Callies Compstar Rods,Wiseco-11 4.030 pistons 9.4:1 comp.,LS3CNC heads,LS3 intake,NW92mm throttle body,ID1000 injectors,BTR trunion upgrade,LJMS STG3 cam,LS7 Lifters,ARP Studs-bolts,Frozen Boost A to W intercooler,JGS 60MM BOV,2 40mmJGS Wastegates,4L80E trans wth segment swap,CircleD 3400 single disk,MOSER 12 3.31gears ,BMR K-Mem.,2 Walboro 450 pumps,Returnstyle fuelsystem MAGNAFUEL regulator.
    LS1Tech sig KRAZY K 2000 TA
    Reply With Quote Reply With Quote
  6. 07-21-2011 #6
    Unreal
    Unreal is offline
    Tuner in Training
    Join Date
    Feb 2010
    Location
    SLC, UT
    Posts
    47
    Tune attached. Any ideas of what to log? It doesn't feel like a FP issue.

    I didn't save the logs but I'll get more tonight.
    Reply With Quote Reply With Quote
  7. 07-28-2011 #7
    Unreal
    Unreal is offline
    Tuner in Training
    Join Date
    Feb 2010
    Location
    SLC, UT
    Posts
    47
    Checked fuel pressure last night. Was solid 58psi at idle and part throttle. Dropped to 30psi as soon as we went WOT. Ordered a aeromotive 340 pump.
    Reply With Quote Reply With Quote
  8. 07-28-2011 #8
    Google
    Google is offline
    Senior Tuner Google's Avatar
    Join Date
    Sep 2010
    Location
    Saint Peters, Missouri
    Posts
    1,303
    Put the stock ve table back in it and post a log with wideband data. You have a vacuum ref. fuel return coming from the fuel rail or close to it or did you put a corvette filter on it?



    ..
    We Can Fix Your Bricked PCM Or Your YYYYYY OS ID
    Reply With Quote Reply With Quote
  9. 08-01-2011 #9
    Unreal
    Unreal is offline
    Tuner in Training
    Join Date
    Feb 2010
    Location
    SLC, UT
    Posts
    47
    Corvette filter in the tank. Like I said, the pump is bad. Doesn't hold pressure at any load. New one on the way.
    Reply With Quote Reply With Quote
« Previous Thread | Next Thread »