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Thread: somewhat sluggish at times

  1. #21
    Lifetime Member LB72004's Avatar
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    if i remember right, it is only about 5% more then stock
    2008 Chevrolet 3500HD DRW LTZ
    285/75/17 Nitto Dura Grapplers, 4.56 gears, Front and rear ARB lockers, Efi Live tuning by me, Raptor 160 LP, Cognito 4-6 NTB Lift, 4" Exhaust, Built Trans by Mike L.

    Sold - 2004 LB7 Duramax, EFI Live with DSP5 Tune
    stage 4 SC transmission, 265/70/16 tires

  2. #22
    Lifetime Member LB72004's Avatar
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    Ok, so i got the blocker plate in. still does it. it seems like it doesn't do it for as long though so it helped but it still has the problem.

    now i am thinking it is just not spooling as fast as it should. any tricks i should try to improve spooling? obviously increasing vane position won't help as the ECM is already doing that. maybe lower timing some?
    2008 Chevrolet 3500HD DRW LTZ
    285/75/17 Nitto Dura Grapplers, 4.56 gears, Front and rear ARB lockers, Efi Live tuning by me, Raptor 160 LP, Cognito 4-6 NTB Lift, 4" Exhaust, Built Trans by Mike L.

    Sold - 2004 LB7 Duramax, EFI Live with DSP5 Tune
    stage 4 SC transmission, 265/70/16 tires

  3. #23
    Lifetime Member Mitco39's Avatar
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    Boost leak? Do another log so I can take a look if you want.

  4. #24
    Lifetime Member LB72004's Avatar
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    ok, i'll do that. any location typical for the LMM that leaks tend to form?

    what's weird is that it only does it about 30~50% of the time. when it doesn't do it it takes off real strong smoke free. when it does do it i can usually lift off of the accelerator and reapply it, the 2nd time it will start to accelerate much quicker with much less smoke and much more boost. this is why i keep coming back to vane position, but i am currently running stock vane table and it still does it so???????
    2008 Chevrolet 3500HD DRW LTZ
    285/75/17 Nitto Dura Grapplers, 4.56 gears, Front and rear ARB lockers, Efi Live tuning by me, Raptor 160 LP, Cognito 4-6 NTB Lift, 4" Exhaust, Built Trans by Mike L.

    Sold - 2004 LB7 Duramax, EFI Live with DSP5 Tune
    stage 4 SC transmission, 265/70/16 tires

  5. #25
    Lifetime Member LB72004's Avatar
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    Sorry keeping you waiting. Did a boost leak test and didn't come up with anything. Was pushing it to about 20 psi and could not find any leaks.

    Anything else?
    2008 Chevrolet 3500HD DRW LTZ
    285/75/17 Nitto Dura Grapplers, 4.56 gears, Front and rear ARB lockers, Efi Live tuning by me, Raptor 160 LP, Cognito 4-6 NTB Lift, 4" Exhaust, Built Trans by Mike L.

    Sold - 2004 LB7 Duramax, EFI Live with DSP5 Tune
    stage 4 SC transmission, 265/70/16 tires

  6. #26
    Lifetime Member LB72004's Avatar
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    i think i got it figured out.

    i lowered the max vane position at the higher rpm and mm3 range and bam, problem seems to be gone. revs much quicker now without any smoke. i think having the vane closed too much can actually hurt spool. looks like having it closed too much will restrict flow so much that the exhaust velocity falls to the point of not being able to turn the turbine faster. open them up a little until you hit max exhaust speed and that will build boost the fastest.

    i ran around chasing all sorts of things but it was a good learning process

    thanks guys
    2008 Chevrolet 3500HD DRW LTZ
    285/75/17 Nitto Dura Grapplers, 4.56 gears, Front and rear ARB lockers, Efi Live tuning by me, Raptor 160 LP, Cognito 4-6 NTB Lift, 4" Exhaust, Built Trans by Mike L.

    Sold - 2004 LB7 Duramax, EFI Live with DSP5 Tune
    stage 4 SC transmission, 265/70/16 tires

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