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11-16-2001, 12:24 PM

Compresion ratio is the volume of the entire cylinder at bottom dead center divided by the volume at top dead center.

Heres a good site that will calculate the compression ratio for you. You obviously need a few specs on your engine.

calculate compression ratio

This one is needed when boost is involved and you have your static compression ratio

compression ratio under boost

Also what you need to know is not the compression ratio but the actual compression of the engine. Basically i is just a gauge that will screw into your plug hole and then you crank the engine over (make sure you have the PGM-FI disconnected) and it will read how much compression is in the cylinder in psi. It is basic way of accessing an engines condiion. It will show if there are bad rings, burnt valves, holes in pistons, basically everything. There is also a wet test but that is not needed until a dry test is done. If you get low readings put a little bit of oil (about 2 spoonfulls) into the cylinder and do the test again. The readings should go up a good bit if it is your rings.

11-16-2001, 12:24 PM	#2
Boosted3g Posts: n/a	Compresion ratio is the volume of the entire cylinder at bottom dead center divided by the volume at top dead center. Heres a good site that will calculate the compression ratio for you. You obviously need a few specs on your engine. calculate compression ratio This one is needed when boost is involved and you have your static compression ratio compression ratio under boost Also what you need to know is not the compression ratio but the actual compression of the engine. Basically i is just a gauge that will screw into your plug hole and then you crank the engine over (make sure you have the PGM-FI disconnected) and it will read how much compression is in the cylinder in psi. It is basic way of accessing an engines condiion. It will show if there are bad rings, burnt valves, holes in pistons, basically everything. There is also a wet test but that is not needed until a dry test is done. If you get low readings put a little bit of oil (about 2 spoonfulls) into the cylinder and do the test again. The readings should go up a good bit if it is your rings.