Compression Ratio Formula

does anyone have the formula to get compression ratio? i have a couple, just not the one i am looking for. i want the one that tells you your compression if you tell it how many cc's of liquid you poured in the spark plug hole with the piston on TDC........etc. help....anyone?

 

I like the calculator at kb-silvolite.com, under tools. seems decent.

 

The Moroso power speed calculator # 8965 does this .

 

Pouring through a spark plug hole can be inaccurate especially on a hemi due to a possible void that can't be filled between the intake and exhaust valve. It's best to make sure the deck on the cylinder being poured is level, in other words you can't do it with the engine in the car.

Here's the formula, however:

Total pour CC's + (displacement x 2.0483*)
Total pour CC's

*2.0483 is for 8 cylinder, 2.7311 for 6 cylinder, and 4.0967 for 4 cylinders.

Example: 103 CC's + (528 cubic inches x 2.0483) divided by 103 CC's equals 11.5:1.

RG

 

You can if you lean the car over at 45 degrees

 

thanks everyone for the responses. Randy....thanks for the formula. i will try it out tomorrow after work. this is the way we usually find our compression ratio, just lost the formula. thanks again