Many enthusiasts use aviation fuel as a blending agent or as a straight gasoline for high-output engines. According to Wusz, aviation gasoline, such as the green 100/130 octane fuel, is generally a lighter specific-gravity fuel that has good octane and a high percentage of alkylate that tends to boost octane. Aviation fuel will work especially well as a blending agent for pump gas but will tend to lean the air/fuel ratio due to its lighter specific gravity of around .69. Also, aviation fuel octane is not rated the same as street gasoline. For example, a 112/160-aviation-fuel-octane rating is equal to 108-octane Unocal 76 leaded race gas.