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Thread: Question on compression and FI

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  1. #1

    Question on compression and FI

    So. My machinist is telling me to go like 6.5 : 1 pistons if i wanna run 12 lbs of boost. Seems a bit low to me considering im going to rebuild the bottom and top with all high performance stuff made to handle a beating. ive heard the 4g64 can handle 5-7 lbs of boost with no modification and be realiable. Thoughts and comments?

  2. #2
    u can boost on stock, and get some good power, even more than 5-7 psi, but 6.5:1 is too low, stock 2g turbo's run 8.5:1...with a 4g64 u can get some great power out of it

  3. #3
    i think ill just run stock and push it up to 10 or so. see how it goes play it by ear. Yea i thought so to. Guys great with machine work not so sure about the rest.

  4. #4
    yeah, i dont remember the exact specs of everything, hopefully a more up-to-date 7ger will post and clarify better

  5. #5
    Member
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    Quote Originally Posted by Iturndawrenches View Post
    i think ill just run stock and push it up to 10 or so. see how it goes play it by ear. Yea i thought so to. Guys great with machine work not so sure about the rest.
    If ur boosting on stock @ 10psi will u harm the engine @ all? also is ur stock motor tuned?
    GWAP STACKIN MAKE'S IT HAPPEN

  6. #6
    Moderator mko's Avatar
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    I was running 10 lbs all day with street tune and it was very reliable. All i did was regular oil changes with good oil.

    If you want responsive street engine you need 9.0:1 CR that will be good in and out of boost, but I have to say that its all in the tune.
    God created turbo lag to give the v8's a brief moment of hope.



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  7. #7
    Senior TGC Member Isaurio's Avatar
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    ^^ cr and tune

    Triple Diamond Motors East Cost
    02 2.5L Fully Built Galant 5 speed
    SOHC Turbo
    http://www.thegalantcenter.org/showthread.php?52330-Isaurio-s-Turbo-Built-quot-4G64T-quot-Heavy-pics>My 4G64 Turbo Built

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