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Thread: Calculating Compresson Ratio

  1. #1
    Senior Member MASTER BUILDER
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    Calculating Compresson Ratio

    I know the bore and stroke of the engine, but not the compression ratio. This is a running engine, i.e. heads on it. How can I figure out the ratio.

  2. #2
    Senior Member RACING JUNKIE
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    Pretty much impossible. If you know the cranking compression, you can get an idea of final dynamic compression.
    -WJ Birmingham

    OneBadGMC.com

  3. #3
    Senior Member MASTER BUILDER
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    I know the cranking compression.

  4. #4

  5. #5
    Senior Member RACING JUNKIE
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    That was a comical read...

    There are, however, enough astute engine builders over on www.yellowbullet.com that can give you a basic idea what the dynamic compression is based on cylinder pressure.

    Specifically, the guys that do the 'pump gas drag' motors. Trying to squeak every last pony out of a given combination by maximizing dynamic compression without detonation.
    -WJ Birmingham

    OneBadGMC.com

  6. #6
    Senior Member RACING JUNKIE
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    ??

    Whats New WJ?
    The MAIN QUESTION Here is................................................ ..............?
    Did the Fellow Ever get His ARM out of the HEADER?
    Later
    G 8)

  7. #7
    Senior Member RACING JUNKIE
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    Quote Originally Posted by OneBadGMC
    That was a comical read...

    There are, however, enough astute engine builders over on www.yellowbullet.com that can give you a basic idea what the dynamic compression is based on cylinder pressure.

    Specifically, the guys that do the 'pump gas drag' motors. Trying to squeak every last pony out of a given combination by maximizing dynamic compression without detonation.
    I agree with this. Lots of smart dudes over there...Just make sure you go to the newbie thread and introduce yourself first. Trust me on that one. :lol:

  8. #8
    Senior Member RACING JUNKIE
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    What a read.... LOL

    That writing craftsmanship was suttle but to the point.....

    I am still trying to figure out who road the best pony on that one... LMAO

    By the way, all of you forgot to factor in the 3/4 duration on that stroke and compression calculation..

    When you get it figured out let me know what you come up with....

  9. #9
    Senior Member RACING JUNKIE
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    Guys, I can't help it I am still rolling over that one. My ribs hurt sooo Bad............ :lol: :cry: :lol: :cry: :lol: :cry: :P

  10. #10
    Senior Member RACING JUNKIE
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    Was a hard lesson learned for the kid repeating bad information like a parrot and then defending it. I bet his buddy caught hell over it.
    -WJ Birmingham

    OneBadGMC.com


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