compression ratio vs boost psi

[s2kadl]

Stock compression is 11:1.

Yeah my tuner is really good, plus Im running on E85 fuel allowing me to run slightly more boost as per 98.

[nd55]

> plus Im running on E85 fuel

I think this has a LOT to do with it.

> say i raised the comp to 12:1 instead of 10.2:1 ill get a better response

I think on a Honda the compression ratio's you'd be considering are in the range of 8 to high 10's : 1.

The 12:1 ratios and higher are specific to highly tuned pushrod V8's turning really high RPM.

I think NASCAR V8's topped out at about 16:1 some time ago, but racing rules have been introduced to limit this with a view to moderating costs.

Higher ratio's are often used when turning really big RPM's and the cylinder VE isn't the best. By squashing a cylinder with an 80% VE with very high CR the cylinder pressure is the same as a 100% VE with less compression.

Not as application on a street engine with an 7000rpm redline.

Any form of alcohol changes this a lot.

Nick.