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Old 11-07-2014, 09:57 PM   #4
franken
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Join Date: Jun 2013
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Posts: 3,152
Re: Compression ratio question

Seem like a .7 difference is a lot since CR is the swept volume of the cylinder vs the combustion chamber volume. I'd say a decimal place was lost somewhere and its more like .07 or .007 in CR.

Of course I'm leaving dish, valve clearances in the piston, and the star, volume created from the gasket, which can simply be added to the stroke, right?

I would think that w/ a 3.48" stroke, adding .015" or .041" won't change things more than a few hundredths of CR.

Area=Pi*D=3.1414*4=12.56 in^2
V=A*thickness
.015*12.5656=0.188484 in^3
.041*12.5656=0.5151896 in^3
3.48*12.5656=43.728288 in^3
See how the gaskets disappear numerically and even in relation to the combustion chamber volume aren't significant.

I googled converting from cc to cuin and got 0.0610237441 so we multiply combustion chamber cc by that and guessing 64cc, we get 3.90cuin.

Go w/ the thin gaskets but you'll never notice the difference.

This is just basic math, realizing the ratios are out of bounds, and putting a few numbers in a calculator. All we need to know is how to calculate the area of a circle, and the volume of a cylinder.

Last edited by franken; 11-07-2014 at 10:22 PM.
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