Dunc

What is the minimum CR that a gasoline engine has to have? Isn't it like 7:1 or 7.5:1? I did search too haha.

This is also in the Engine Theory section, but they seem to be a little slow with the knowledge bank.

grndcont

alright, what do you have planed?

Dunc

Nothing, I'm already built and done with that stuff haha. But I always run into the people who say that you need to use like 7:1 for anything over 400whp+ (which is completely assine). So I want to know this bit of info., that way I can respond with "alright captain dumbass, you have to have _._:1 CR for your car to even move".

grndcont

see where you are going. i like 9:1 for most aluminum head situations up-to 550-600 hp. then meby 8.5 or 8:1 from there. of "course some may have experience/luck with other setups. but back to the og prob, i don't know, meby 6 or 7:1. im in for an update, + I'll look into my engineering books for anything.

Dunc

cool thanks....I've been google-ing it also, but I'm getting jack squat

sewell94

My porsche is 6.5:1. I've read of engines that ran on Cr as low as 4.7:1.

markaria

early 930? Gotta love those!

sewell94

Yes, Its a 76 930. its all apart right now, nothign like stock. i am using stock pistons and rods though. Everything in the engine is cryo'd and coated. Running twin gt35's. Twin plug, accel dfi, 8 1000cc inj, etc etc. Should make a good 850hp or so