Originally Posted by 1stGenCRXer
Tell that to all the bent valves I've seen.
To clarify, just about any VTEC head you add on is going to bump up the compression of the stock B20, which is already pretty high for a non-VTEC Honda. [also, USDM B20z and JDM B20b are about the same CR]
What you consider high compression, and what I consider high compression on a street engine are obviously two different things. Regardless of what the CR calculates out to be, any pistons used in this kind of setup need special attention to make sure they don't have issues with the cams you plan to run. Also keep in mind that the lift during overlap has to be taken into account if you were to change cams later.
Regardless, stock pistons, and not much else done to increase CR is still enough to make about 230 at the crank under Honda Challenge H1 rules with a B20VTEC.
If you up the compression w/forged pistons then you don't need to worry as much about valve-to-piston clearance. Most aftermarket pistons have a lot bigger valve reliefs than OEM, especially compared to a B20's. And thats also why you clay your motor before hand so you know that all your clearance are within spec.
Originally Posted by BoostedITR41
10:1 is not high compression at all.....11.5:1 and up is high compression on a street motor
Amen to that
