what's the highest compression that can be achieved w/ out detonation or having to upgrade to racing fuel?

 

I had that same question, when I got my head milled. I have been told anything over 12 usually requires some kind of octane booster. I'm pretty sure that you can run 11:1 with standard premium, but do a search on the net if you want a proffesional answer, that's just what the import shop told me.

 

doesn't the Z06 have compression above 12:1?

 

12.5 is right on the border, anything above you cant run on pump gas.