Re:Z6 pistons in a ZC... what c/r will I have?
 

im well aware that low comp engines are ---- slow off boost, and that if you can fuel it that high compression is fine for boost.... especially since most turbo conversions rarely run more than 1 bar...

we have out wires crossed here....

i know of a bloke (friend of a friend) who runs a ford sierra cosworth with 6. something CR, but its a WRC spec engine with pectel L8 ecu and antilag he gets 22psi at idle!!!

You make horsepower by how much air you move through the motor. A high compression 10:1 engine is more efficient than a 7:1 engine, so the 10:1 engine gives you more bang for the buck. However, because the lower compression is not as efficient, it will move more air through it. So, at 15 PSI of boost, the 7:1 engine will have an effective compression ratio of 14:1, will not be into detonation, and be moving more air, making more horsepower than the same conditions for the 10:1 engine. That engine will be in self-destruct mode, have detonation, and an effective compression ratio of 20:1!
This is why the racers only run 5:1 or even 6:1. All of this is great for a drag car, but because the static compression is lower, you will not have much bottom end torque either. So, since most of us don't drag race every place we go, a good compromise would be 8:1 or 8.5:1 compression. This way you don't loose too much bottom end for driveability, and if you don't run too much boost, say 10 to 15 PSI, you stay away from the gray effective compression area of 15:1 and up.

Re:Z6 pistons in a ZC... what c/r will I have?
 

oh, and ive driven a n/a renault 5 1.4 campus, incredibly slow....

Re:Z6 pistons in a ZC... what c/r will I have?
 

I bet their isnt one person running anything lower than 9.1 in NIRA

Re:Z6 pistons in a ZC... what c/r will I have?
 

http://www.honda-tech.com/zerothread?id=267641


You guys might want to check that link out. Supra pistons+b16a connecting rods+ a little block modification= ~9.5 c/r in most Dseries engines...

Re:Z6 pistons in a ZC... what c/r will I have?
 

I bet their isnt one person running anything lower than 9.1 in NIRA


and i bet they dont need their engines to last 20000 miles between rebuilds either!

Re:Z6 pistons in a ZC... what c/r will I have?
 

dude, they replace the engines after each season, at about 30-40 passes a year and about 40-50 hours of dynoing, They probably have less than 4000 miles on them.

Jeff