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Old 06-24-2004, 09:35 AM
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Originally posted by blndweasel
Isn't that formula in the Ford Catalog just a Static Compression Formula? It doesn't include anything for intake closing ABDC.........
You are correct about the formula.

In order to use it to determine the DCR, you would have to calculate the position of the piston in the bore relative to the closing of the intake valve.

Say the intake closed at 45* ABDC. You will need to figure out how far the piston moved up the bore ABDC and subtract that amount from the volume at BDC.

Knowing that figure, you could use the formula in the catalog.

I think.

But I'm with you. I'd sooner trust the calculator you listed than my own math/method.
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