Does anyone know of a formula to determine the compression ratio by measuring cylinder pressure? And yes, I know that the static compression ratio is affected by LSA and duration, etc, which makes it very difficult to determine the true CR. It seems to me that for a given swept volume, the cylinder pressure produced should have a corresponding compression ratio value, which would be the true compression ratio??? Thanks in advance!

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David
68 SS Camaro
72 Chevelle
73 Nova Hatchback

There is a device, I believe it is known as a P&G meter, but they are expensive, and only tech people like Nascar have them. Short of pulling the heads off and measuring everything, you can only guess.

Are you asking what percentage of the cylinder volume is in the cylinder when the intake valve closes? Book by Ed Staffel "Chevy Rat Motors" That goes into detail on how to select a cam for compression ratio and cylinder swept volume. Desk top Dyno is mentioned in and the book has a good example on how to select a cam for the fuel type and etc. I don't know if this will help, but it opened my eyes on how to select cams for my engine which will be on pump gas.

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