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Thread: Injector PW & Duty Cycle

  1. #1
    Lifetime Member
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    Default Injector PW & Duty Cycle

    In a drag race only vehicle and you hit 100% duty cycle can you raise the fuel pressure 20% (60psi to 72psi) then reduce your MAP VE 20% accross the board and come out the same AFR? Or is their a different formula to use without starting over on the VE tables?

    Thanks,

    Lee

    230" Dragster - 2000 LS1, 02020003 Speed Density, PRC 2.5 Heads,
    MS3 Cam 237/242 .603/.609, Vic Jr. intake, Holley 1000CFM TB,
    PowerGlide, 5000 stall converter. 8.70@154 MPH

    My Projects Homepage: http://www.horsepowerracing.com

  2. #2
    Lifetime Member ChipsByAl's Avatar
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    Sorry Lee but it does not work like that. Fuel pressure rise vs. delivered fuel through the injectors is not a linear equation. Check out Russ Collins' web page for an online formula.
    http://www.rceng.com/technical.aspx#...ressure_Change
    To be accurate after any fuel changes you should put a wide band AFM to verify the change.
    Al
    "Trash that carb and get Injected!"

  3. #3
    Member Ritch's Avatar
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    any concerns about increasing pressure to 70+ lbs? I am considering this.
    ____________________________
    1999 GMC, rcsb, 2wd, 5.3, XR275HR-12
    Radix magnacharger mp112
    Long tubes true duals, $L60E

  4. #4
    Lifetime Member johnv's Avatar
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    If your VE table is dialed in you should be able to raise fuel pressure, then rescale injector flow rate table useing one of the spread sheets floating around (do a search)

    then you should be good to go
    Back yard boost
    347+ T76 = 770 rwhp 10.96 @ 135 mph

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