highest compression M20 on pump gas?

[ptownTSI]

Just curious but has anyone made a high compression M20 that could still run on 91 or 93 octane. With the right cam I think you could do 11.5:1 without detonation, especially since M20's have AL heads from the start. Domestic V8's are running compression that high with aluminum heads, cam and a good tune.

[153624]

I have pinging issues with my stock seta on 89. I would hate to drive it with any higher compression.

I am interested in this also. Going to rebuild next year.

[nando]

10:1 works pretty well with 92, 11:1 would work fine with an agressive cam.

[nando]

I have pinging issues with my stock seta on 89. I would hate to drive it with any higher compression.

I am interested in this also. Going to rebuild next year.

you probably have heavy carbon deposits, or perhaps it's running lean - seeing how all the M20s were designed to run on 87 octane, it's not the compression ratio that's causing it.

[ptownTSI]

anyone ever looked into cylinder head/piston coatings. They are supposed to let you run even more compression without detonating and are really good on forced induction motors.