units of compression ratio?

05-02-2003, 09:31 PM
does anyone know the units of compression ratio? What is it the ratio of? I was thinking it might be the amount of air per amount of gas that can be squeezed into a cylinder but im not sure.

05-02-2003, 10:12 PM
Compression ratio isn't measured in any units :) This is why it is called a "ratio" - something divided by something.

read up here (http://e30m3performance.com/myths/more_myths1/comp_ratio/comp_ratio.htm)

And a little quote from the page:

"Compression ratio if defined quite simply as the volume above the piston at bottom-dead-center (BDC), divided by the volume above the piston at top-dead-center (TDC)."

05-03-2003, 01:34 AM
Yeah, a ratio like this (volume over volume) is inherently unitless.

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