Octane
Gasoline, or petrol as it is called is a liquid used in an internal combustion engine. This source of fuel is more volatile than diesel oil, kerosene, and even some jet fuels. Because of this volatility, when compressed in an ICE, the pressures generated significantly raise the temperature of the fuel mixture. In many high performance engines, this easily ignited fuel is not preferable as these engines operate at higher compression ratios than say an economy vehicle.
The chemical octane, present in all gasoline is a hydrocarbon, which is responsible for the level of volatility. The higher the research octane number (RON) the less volatile the gasoline. This means that an engine can compress the fuel more creating a denser fuel charge and more energy. Engines that are force induced or have high compression ratios will not cause pre-ignition, or knocking, which is bad. Modern engines can have high compression ratios and forced induction with low octane gas because of the advent of new technologies.