Octane is a measurement of a fuel's resistance to ignition. Detonation is a state that occurs when fuel in an internal combustion engine ignites before the spark plug fires.

Yeah, our cars will run on 87 because the knock sensor will tell the computer to retard the timing so the engine won't knock and ping. Running 91/93 octane will keep the knock sensor happy and allow the computer to add more timing which will allow the engine to make more power and more power means better performance and to a degree better gas mileage (more power to move the same amount of weight, the engine doesn't have to work as hard).

You think really high octane gas won't hurt your engine? Go fill up with some c16 and drive around. It won't be fun, trust me.

 

I run 93 all the time because I dont allow any knock retard in the computer and I have 41degrees advanced timing at 4000 rpms untill heaven. No knock at all even with that cam in my sig.

Basicaly the high the octane the slower it will burn. just think of it that way. thats why higher compresion motors needs higher octane because they burn fuel faster thus need a slower burning fuel.

 

Here's everything you wanted to know about gasoline, but were afraid to ask.

http://www.faqs.org/faqs/autos/gasoline-faq/part1/