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Thread: WOT bog from a stop. Lean Spike. Ideas?

  1. #1
    Member tunedportcj5's Avatar
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    Default WOT bog from a stop. Lean Spike. Ideas?

    From a dead stop @ idle (in or out of gear) and you hit WOT - I get a bog/hesitation and then it clears up over 2600 rpm or so. I am commanding 1.00eq throughout the entire table (for VE tuning). VE table is happy, car runs excellent at all other RPM ranges - except off idle WOT.

    When I hit WOT - it stumbles and the wbo2 maxes out at 20afr (lean spike.. right?) After hitting at least 20 or so counts on the AUTOVE. The 95-105MAP @ 1200-2400 RPM say I need to add 20% to the VE on those cells.

    I've added over 40% and nothing seems to change.

    A little about the car:

    '98 Z27 A4 3600VIG 3.73s
    Cam only LS2 240/244 .598 .610
    Fast 90/NW 90
    SVO 42s
    Racetronix fuel system
    ...and all of the other usual boltons

    It seems pretty obvious this lean spike is causing my bog. I am not getting any KR but my timing appears to be dropping down to single digits and I cannot figure out why.

    Would someone mind looking at my logs and tune? (please ignore the skewed VE table)

    Thanks,
    David
    '94 Lexus SC300 LY2 4.8, LS6 cam/springs, E38, LS3 MAF, LS2 intake, 88mm TB, 2bar MAP, T42/4L80e, mpt70
    www.terratraction.com/gallery

  2. #2
    Lifetime Member jfpilla's Avatar
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    With your drivetrain you should be easily breaking the tires loose. Is it possible TCS is active and pulling timing?
    2003 red vert
    Mods:
    LS7 crate engine, wet sump, 24xx reluctor
    LPE 100mm MAF
    Vararam, cold air intake and bridge
    RPM Level 6/4L60e trans
    3.42 gears
    Yank SS3600
    1-7/8" AR headers
    Z06 exhaust
    470rwhp 437rwtq
    1/8th mi-1.526-60'-6.862-1/8th-@100.74mph

  3. #3
    Member tunedportcj5's Avatar
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    no TCS.... oh, it will break the tires loose. Just after the Boggg..
    '94 Lexus SC300 LY2 4.8, LS6 cam/springs, E38, LS3 MAF, LS2 intake, 88mm TB, 2bar MAP, T42/4L80e, mpt70
    www.terratraction.com/gallery

  4. #4
    Joe (Moderator) joecar's Avatar
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    Exclamation

    I don't know why you get lean during WOT... but...

    don't run your engine with OLFA/PE commanded EQ 1.0 everywhere...
    this is too lean and will surely destroy your engine
    ...
    I am surprised you're not getting knock detected...

    I'm no boost expert, but that's way too lean for boost.

  5. #5
    Member tunedportcj5's Avatar
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    Quote Originally Posted by joecar
    I don't know why you get lean during WOT... but...

    don't run your engine with OLFA/PE commanded EQ 1.0 everywhere...
    this is too lean and will surely destroy your engine
    ...
    I am surprised you're not getting knock detected...

    I'm no boost expert, but that's way too lean for boost.

    I'm N/A.. no boost. I have since modified the upper MAP values for more fuel. Somewhere around 1.17eq.
    '94 Lexus SC300 LY2 4.8, LS6 cam/springs, E38, LS3 MAF, LS2 intake, 88mm TB, 2bar MAP, T42/4L80e, mpt70
    www.terratraction.com/gallery

  6. #6
    Lifetime Member Biggsy's Avatar
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    Well, your single figure digit timing figure is actually what is being called for off your timing table, nothing is pulling it back.
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    Last edited by Biggsy; December 1st, 2007 at 11:05 AM.
    Dave.

  7. #7
    Member tunedportcj5's Avatar
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    Thanks Dave. I'll take a look and bump up the values in those cells!

    Thanks,
    David
    '94 Lexus SC300 LY2 4.8, LS6 cam/springs, E38, LS3 MAF, LS2 intake, 88mm TB, 2bar MAP, T42/4L80e, mpt70
    www.terratraction.com/gallery

  8. #8
    Lifetime Member Biggsy's Avatar
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    I hope I read your previous post right, you have now richened up WOT from EQ 1 now?

    28 Deg timing and EQ1 on my car will make lots of little bits of my pistons!

    22 Deg (+/- 2 Deg) and AFR 12.5 @ WOT (LS1 not modified) keeps mine nice and safe. Leaner makes slightly more power but I don't like having my cars "on the edge", better (in my opinion) to comprimise a little power to keep motor safe.
    Dave.

  9. #9
    Member tunedportcj5's Avatar
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    You are right... I don't run EQ1 at WOT at the upper RPM range. It was only set at 1.00 for AUTOVE tuning. Remember - I am only trying to fix the off idle WOT stumble/bog.

    Thanks!
    '94 Lexus SC300 LY2 4.8, LS6 cam/springs, E38, LS3 MAF, LS2 intake, 88mm TB, 2bar MAP, T42/4L80e, mpt70
    www.terratraction.com/gallery

  10. #10
    Lifetime Member jfpilla's Avatar
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    Quote Originally Posted by tunedportcj5
    no TCS.... oh, it will break the tires loose. Just after the Boggg..
    I'm surprised that your programmed timing at low rpms has any affect. With a 3600 stall and 3.73's you should flash right passed that timing.
    I hope you let us know if raising timing down low helps.
    Did you mean your car has no TC or that you disabled it?
    2003 red vert
    Mods:
    LS7 crate engine, wet sump, 24xx reluctor
    LPE 100mm MAF
    Vararam, cold air intake and bridge
    RPM Level 6/4L60e trans
    3.42 gears
    Yank SS3600
    1-7/8" AR headers
    Z06 exhaust
    470rwhp 437rwtq
    1/8th mi-1.526-60'-6.862-1/8th-@100.74mph

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