Octane FS1 is approved for all gasoline-ethanol mixtures and has been tested in mixtures of 5%, 10%, 15%, 50% and 85% ethanol. Octane FS1 is also compatible in engines that utilize catalytic converters and forced air induction systems such as turbochargers, superchargers, and compressors. Can be used in 2 and 4 stroke gasoline engines.