Originally Posted by
InsaneCivicCoupe
I highly doubt your motor is 8:1 with 165-170psi compression... The easiest way to determine compression ratio based off cranking pressure is a simple formula... A 1:1 ratio is equal to 0 PSI. 14.7 PSI is equal to a 2:1 ratio. Just multiply your ratio by 14.7 to get PSI, or divide PSI by 14.7 to get ratio.
For example, 165psi / 14.7 = a ratio of 11.22:1 or 170psi / 14.7 = 11.56:1
Mine would be 120psi / 14.7 = a ratio of 8.16:1 or 125psi / 14.7 = 8.50:1
Hope that helps
That formula also go's hand in hand with a chart that gives you a range of cr's that it could be. If that formula was accurate a typical ls is roughly 190psi at 9.2 but if you use that formula it would come out to 12.9. My last build was a b20/vtec at 13.0-1 and it had a compression on 280 which would be a cr of 19.0.
Ill look for the chart that goes with the formula.
Either way it is a nice build.
bump