What is the highest compression ratio you can run with 101 octane fuel? I am running 11.8 to 1 right now on 93 with no KR. I want to go with 13.5 to 1, just want to make sure I can do it on 101 'cause we have a local station that you can buy 101 right out of the pump 24 hrs a day

TIA!!!!!

 

14.5 will work good

 

It also depends on the shape of the combustion chamber, timing and port shape (which effects swirl). The these things wrong, and you can't run much compression at all.

 

yeap i agree, running that high a CR will need some very special head work, i think C5R with extensive work.

 

I've got a set of AFR 225's to go on it. Would I be safe with those heads and 13.5 to 1?

 

Your cam timing will also play a big part in determining how much compression your fuel will support without detonation, as well as how good your heads are, and other things. How good your intake flow is as well as when your intake valve closes determine in large part the volume of air and fuel available for you to compress. You can up your compression and spread the lobes or add duration or both to close the intake valve a little later.

 

I was gonna go with the TSP Giant cam and I have a 90mm FAST LSX intake setup to go on it. Do you think that 13.5 to 1 will be pretty safe, or do I even need that much compression? AFR said to put the 225's on a stock cubic inch motor I would need high compression, and TSP said that that big of a cam wouldn't be suitable for a stock cube bottom end without high compression. I just want to squeeze every bit of power out of this engine that I can. How high is high enough??

 

TTT please help!!!

 

ttt please