Compression Question

[crazykid]

Hello, I have a question about compression, i am looking at a head that is advertised as 15-1 compression. what would this work out to as far as psi numbers or type of gas that needs to be used. Is it the higher the first number the more compression or is it the other way around? Thanks

 

[grapeape]

stock is around 9-1 depending on model. 15-1 requires race gas, but it still sounds high.

 

[crazykid]

Thanks for the reply,That is what i thought. Thanks

 

[valin]

A 15:1 setup would require 112-114 octane fuel, depending on pipe design and ignition timing. The resulting cranking compression is dependant on the height of the exhaust port.

Also, stock '98-99 SRX compression ratio is just under 10:1, 2000+ SRX ratio is just over 10.5:1