The octane rating of gasoline tells you how much the fuel can be compressed before it spontaneously ignites. When gas ignites by compression rather than because of the spark from the spark plug, it causes knocking in the engine. Knocking can damage an engine, leading to detonation or preignition. Lower-octane gas (like "regular" 87-octane gasoline) can handle the least amount of compression before igniting.
The compression ratio of your engine determines the octane rating of the gas used in the car. The compression ratio of an engine is the Ratio between the volume when the piston is at BDC (bottom dead center) to the volume remaining at TDC (Top Dead Center) There are several ingredients in creating more horsepower of an engine, one way is by an increasing its compression ratio. Simply put Higher compression ratios increase combustion pressure which in turn requires a higher-octane fuel. The proper Piston, Cylinder Head chamber size along with the right camshaft selection will be determining factors in this. We have found that to get the most out of a street driven vehicle, to keep compression in the range of 9.0-10.0 to 1. Running ratios in excess of this is usually asking for trouble unless it's for race purposes only. The Good new is Engine Factory engines rarely exceed over 10.5 to 1 compression. Engines running up to 9.5 to 1 compression will run fine on 87-89 octane. Compression numbers in the 10 to 10.5 to 1 range, we would be suggest using a 91-94 octane.
1-800-704-5385