FUEL

[Geo]

An octane rating theoretically has nothing to do with an engines power production. Octane is simply a measurement of the engines ability to resist detonation. [/b]

Correct.

Every engine has an octane requirement. Using more octane could, again theoretically, hurt power. Geeks speak on gasoline.
http://www.faqs.org/faqs/autos/gasoline-fa...3/preamble.html
[/b]

A very good read.

The point in the rev range where the engine is most susceptible to detonation is at peak torque (peak cylinder pressure). So the adage of using higher octane for protection in an extended high rpm situation isn't all together valid.[/b]

IIRC Motor Octane Number (MON) was developed as a direct result of Research Octane Number (RON) not being useful in situations that contained sustained high speed running, i.e., the Autobahn. It's covered in the Gasoline FAQ.

[orlando_wrx]

edit- Just read the article and see that they do indeed list the testing methods of RON an MON, so I'm deleting my post to avoid repetition.

[Geo]

Actually MON was created to more closely rate the octane as vehicles consume it under load, seeing as how the controlled environment of the RON test didn't relate to average operating conditions. As the RON uses a CFR (combustion fuel research) engine, MON tests use basically the same setup with a few variables.
[/b]

Indeed.

However, a bit of history..... (from the Gasoline FAQ)

"During the late 1940s - mid 1960s, the Research method became the important
rating because it more closely represented the octane requirements of the
motorist using the fuels/vehicles/roads then available. In the late 1960s
German automakers discovered their engines were destroying themselves on
long Autobahn runs, even though the Research Octane was within specification.
They discovered that either the MON or the Sensitivity ( the numerical
difference between the RON and MON numbers ) also had to be specified. Today
it is accepted that no one octane rating covers all use. In fact, during
1994, there have been increasing concerns in Europe about the high
Sensitivity of some commercially-available unleaded fuels."