Calculating Compresson Ratio

Old 08-09-2009, 08:32 AM
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jreiley
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Default 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.
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Old 08-09-2009, 09:39 AM
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OneBadGMC
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Pretty much impossible. If you know the cranking compression, you can get an idea of final dynamic compression.
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Old 08-09-2009, 10:03 AM
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jreiley
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I know the cranking compression.
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Old 08-09-2009, 12:21 PM
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Tod74
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OH NO......

http://forums.racingjunk.com/viewtop...mpression+test
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Old 08-09-2009, 01:07 PM
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OneBadGMC
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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.
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Old 08-09-2009, 01:23 PM
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bbchevy
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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)
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Old 08-09-2009, 02:04 PM
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Tod74
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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:
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Old 08-09-2009, 04:11 PM
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ashbros
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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....
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Old 08-09-2009, 04:12 PM
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ashbros
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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
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Old 08-09-2009, 04:39 PM
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OneBadGMC
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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.
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