calculating compression ratio under boost.
 

http://www.howstuffworks.com/framed....rbo.html#turbo

on this page is a formula where you can calculate the compression ratio under boost.
When I take this formula with my datas I have a cr of 5.5psi/14.7psi + 1 x 11 = 15.1:1 compression ratio under full boost. It is not too much.

A Audi S3 has a cr of 9.5:1 and about 12psi boost. (12/14.7 + 1 x 9.5) = 17.3:1 cr!!! WTF

I know a Nissan 200 which makes 300hp to the crank (in US I think it is the 180) with 10:1 cr and 1.1BAR boost (16.17psi)
HE has a cr of 21:1 under full boost http://images.zeroforum.com/smile/emwink.gif EXTREM.

NOTE: 1 BAR = 14.7psi.

All I think I can safely boost 8psi (that would be 17:1 cr) without detonation or hurting daily driveability. CORRECT?!?!

Give me your statements please!

Re: calculating compression ratio under boost. (austrian ITR)
 

Assuming that your fueling and ignition tables are correct, then yes, you could run that amount of boost, and more. But...

But, the problem is that roots type blowers such as yours lose their effeciency fast when you raise the boost. Without an intercooler, the charge temp gets too hot, detonation occurs, and your motor goes in the toilet.

Re: calculating compression ratio under boost. (VaporTrail)
 

Yes, but I´m thinking about to get the JR water-injection to cool down the air.