I was just curious if anyone knew at what is the highest compression ratio an F20 can run on pump gas (91/93) without having to pull timing?

Not that I'm planning to raise the compression anytime soon, but just out of curiousity I'd like to know.

 

for 91 oct it's 11.5

for 93 i'm not sure. .but i believe it's 12.1 or 12.5

 

12-12.4 will be safe.

 

Im running 12.0:1 on 93 octane with no problems. The thing that you need to look at is Timing Advance. You can run 13.0:1 on 93 octane but your timing with not be as high. I run 12.0:1 wiseco pistons and Inline Pro is using 13.0:1 compression. Once Im done tuning I would love to compare the timing maps.

 

S2000Talk is a better place for this.