what the numer 9.2:1 in a piston means?

[hierro0430]

Hey guys i have this question. In a piston what this number means and how you get this numer? is there any formula (math) to get to this numer. thank you for your time ..

 

[Drackonn]

that looks like a compression number - those would be good for boost or nitrous - running 9.2:1 compression N/A would be a bad idea ... but I could be completely wrong

 

[Szady]

You can run 9.2:1 CR N/A....you'll just be slow as balls. Generally, higher CR for N/A, and lowr for boost.

 

[Steven.]

whats a numer?

 

[Billy.]

9.2:1 is the volume ratio of your cylinder at BDC compared to TDC. look at it like you are craming 9.2 units cubed of air into 1 cubic unit of space. the taller the piston = the higher the ratio number = the more power the cylinder makes