S281 E

^+1 higher octane fuel will not give you better gas mileage and will not benefit you without the proper tuning.

PNYXPRESS

The octane rating has little to do with combustion. It is all about the ability to be compressed. Gasoline is made of octane and heptane. Heptane will spontaneouly combust as soon as it begins to be compressed, Octane can be compressed all you want. By running a righer rating of octane it lowers the amount of heptane in the fuel, allowing the piston to reach closer to TDC and the ignition of the spark plug before the fuel begins to combust on its own. By delaying this reaction the force on the piston is more on the power stroke and not still on the compression stroke. This allows the engine to work more efficiently and use less fuel to do the same work. So yes higher octane fuel will increase mpg, but there comes a point when it is not cost effective with the price difference.

Diabolical!

None of this happens if you don't have a SPECIFIC TUNE for higher octane. Your plugs will spark at the same time and compression they did with the lower octane fuel yielding zero additional fuel mileage.

PNYXPRESS

Wrong- the Heptane in the gasoline doesnt care what tune you have, it starts to spontaneously detonate with the least bit of compression due to the piston moving up in the cylinder. When this happens while the piston is still in the compression stroke(which doesnt matter what kind of tune you have) the piston is working against the explosion.

Diabolical!

That's called detonation, and it means that your fuel is combusting too early. Man, I'm trying to be polite, but you have no idea what you're talking about. This type of stuff is a huge part of my professional background. When you argue a point no matter how wrong you are, you really start to look silly and you certainly don't gain the respect of the person you are arguing against. All the best.