I know I'm splitting hairs a bit, but octane is the measurement relative to the proportions of iso-octane and n-heptane. An 87-octane gasoline, for example, has the same autoignition resistance, or octane rating, as a mixture of 87% by volume of iso-ocatne and 13% by volume of n-heptane. The octane ratings of n-heptane and iso-octane are respectively exactly 0 and 100, by definition.
Aviation and racing fuel 'octane' numbers are an accepted misuse of the word octane. They get those higher than 100 numbers via Benzene, Methane, Ethane, Toluene, Xylene.
It would be a bother to say "well it's like 100 'octane', but 13 clicks better," and so 113 octane it is. In the abstract, it's not too far from "Kleenex" meaning facial tissue.
Tune in again next week folks, for yet another episode of Bucky's Boring Fuel Facts!
