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Thread: LT4 pulley upgrade. Changing pulley number in tune?

  1. #1
    Tuner in Training
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    LT4 pulley upgrade. Changing pulley number in tune?

    Do you guy change the pulley number in the tune? or just leave as is and tune normally?
    AIRFLOW - SUPERCHARGER - PULLEY RATIO

  2. #2
    Senior Tuner Higgs Boson's Avatar
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    I change it but not sure if it does anything.

  3. #3
    Advanced Tuner Ghostnotes's Avatar
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    Be nice if it does, like a master modifier for the air models...
    I always tune VVE....
    2016 C7 M7 Z51
    Callies ultra billet crank
    Callies ultra billet rods
    Diamond pistons
    Jhonson high speed lifters
    Ported and polished headwork
    Custom cam
    YSi-V7

  4. #4
    Senior Tuner Higgs Boson's Avatar
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    Quote Originally Posted by Ghostnotes View Post
    Be nice if it does, like a master modifier for the air models...
    It definitely doesn't do that, lol.

  5. #5
    Advanced Tuner Ghostnotes's Avatar
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    I know, that would be too easy...
    I always tune VVE....
    2016 C7 M7 Z51
    Callies ultra billet crank
    Callies ultra billet rods
    Diamond pistons
    Jhonson high speed lifters
    Ported and polished headwork
    Custom cam
    YSi-V7

  6. #6
    Senior Tuner
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    My ratio doesn't match anyway. 8/2.5=3.20. My file has 2.99 ratio.

    Actual measured dimensions are 8.051 and 2.505 = 3.21 ratio.

  7. #7
    Senior Tuner Higgs Boson's Avatar
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    i have 2.71 in mine for a 9.5 lower and 3.5 upper

  8. #8
    Senior Tuner
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    Quote Originally Posted by Higgs Boson View Post
    i have 2.71 in mine for a 9.5 lower and 3.5 upper
    Did you make the change before you tuned your car? I would hate to change mine now to correct and it does something to afr or whatever. I installed an 8 3/4" crank pulley and left this block stock. Hopefully it's just a reference in our tunes.

  9. #9
    Senior Tuner Higgs Boson's Avatar
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    I really don't think it will change anything.

  10. #10
    I am not seeing that table in my 2018 ZL1. Under airflow, all I have is a turbocharger tab.

    Does anything need to be changed under: torque management / SC boost control or supercharger ? There is max pressure under boost limits that is set to 180 kpa from the factory.

    Any tips would be appreciated. I just installed a 2.30 upper, nothing major.