Quote: Originally Posted by Jbird 100% octane, put that in ur car and see what happens, might lose an eyebrowe or more Octane is a rating not a physical thing. 100% octane is like having 100% horsepower in an engine.

Lol WUT

The octane rating is a measure of the resistance of gasoline and other fuels to detonation (engine knocking) in spark-ignition internal combustion engines. High-performance engines typically have higher compression ratios and are therefore more prone to detonation, so they require higher octane fuel. A lower-performance engine will not generally perform better with high-octane fuel, since the compression ratio is fixed by the engine design. The octane number of a fuel is measured in a test engine, and is defined by comparison with the mixture of iso-octane and normal heptane which would have the same anti-knocking capacity as the fuel under test: the percentage, by volume, of iso-octane in that mixture is the octane number of the fuel. For example, gasoline with the same knocking characteristics as a mixture of 90% iso-octane and 10% heptane would have an octane rating of 90.[1] Because some fuels are more knock-resistant than iso-octane, the definition has been extended to allow for octane numbers higher than 100. [edit] Definition of octane rating Octane rating of a spark ignition engine fuel is the detonation resistance (anti-knock rating) compared to a mixture of iso-octane (2,2,4-trimethylpentane, an isomer of octane) and n-heptane. By definition, iso-octane is assigned an octane rating of 100, and heptane is assigned an octane rating of zero. An 87-octane gasoline, for example, possesses the same anti-knock rating of a mixture of 87% (by volume) iso-octane, and 13% (by volume) n-heptane. This does not mean, however, that the gasoline actually contains these hydrocarbons in these actual proportions. It simply means that it has the same detonation resistance properties as the described 'standard' defined mixture. Octane rating does not relate to the energy content of the fuel (see heating value). It is only a measure of the fuel's tendency to burn in a controlled manner, rather than exploding in an uncontrolled manner. It is possible for a fuel to have a Research Octane Number (RON) greater than 100, because iso-octane is not the most knock-resistant substance available. Racing fuels, AvGas, liquefied petroleum gas (LPG), and alcohol fuels such as methanol or ethanol may have octane ratings of 110 or significantly higher — ethanol's RON is 129 (102 MON, 116 AKI). Typical "octane booster" gasoline additives include tetra-ethyl lead, MTBE, and toluene. Tetra-ethyl lead (the additive used in leaded gasoline) is easily decomposed to its component radicals, which react with the radicals from the fuel and oxygen that start the combustion, thereby delaying ignition and leading to an increased octane number. However, tetra-ethyl lead and its byproducts are poisonous, and the use of tetra-ethyl lead creates an environmental hazard. Since the 1970s, its use in the United States, and most of the industrialised world has been restricted. Its use is now generally currently limited to being an additive to aviation gasoline. Research Octane Number (RON) The most common type of octane rating worldwide is the Research Octane Number (RON). RON is determined by running the fuel in a test engine with a variable compression ratio under controlled conditions, and comparing the results with those for mixtures of iso-octane and n-heptane. The only engine used to get these figures is a Waukesha engine used on a global scale much thanks to wikipedia, hope this sheds some light on the subject