wallace compression boost calculator

Discussion in 'Manton Push Rods Top Alcohol Tech Questions' started by blownapex, Nov 2, 2017.

  1. blownapex

    blownapex Member

    May 25, 2006
    Likes Received:
    using the wallace compression boost calculator should i go by the standard way or the effective way
    its a big difference

    my set up now 128 od c screw bae fat head
    10.6:1 ,60 psi, 2500 ft std = 53.37:1
    effective =23.40:1
    new set up 75 od c screw
    i think boost will be around 38 psi (chime in if different)
    12.6:1 ,38 psi, 2500 ft std =44.67:1
    effective =23.36:1

    now this is std which seems very high and dont want to find out hard way
    15.0:1 ,38 psi, 2500ft std = 53.28:1
    effective = 27.9:1

    so which one do i use

    im just trying to keep cyl pressure same as with 128 od but i dont know which one to use

    i dont think i could get 15:1 on a bae hemi anyway

  2. jay70cuda

    jay70cuda Member

    Sep 30, 2009
    Likes Received:
    Wow. That’s a hell of a calculator. 15:1 on a screw. The tuning window on that would be none existent. I can’t believe that people would use that.

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