Topic summary
high-octane
Extracted from the Wikipedia article Octane rating.
Effects
The other rarely-discussed reality with high-octane fuels associated with "high performance" engines is that as octane increases, the specific gravity and energy content of the fuel per unit of weight are reduced. The net result is that to make a given amount of power, more high-octane fuel must be burned in the engine. Lighter and thinner fuel also has a lower specific heat, so the practice of cooling the engine by means of running a rich fuel to air ratio requires an ever-increasing amount of fuel as octane increases.