These calculators are rough approximations and none of the numbers here are absolute. There are many other factors such as head material, timing, and direct injection that come into play. Modern engines can handle much higher compression at lower octanes. Careful tuning is the best way to determine your actual octane needs.

Compression Factors


Air/Fuel Ratio

Combined CR: 13.01

Recommended compression per octane
12:1 93 Pump
14:1 110 oct.
15:1 C116 oct.