Octane Ratings

[wolosp]

I've just returned to the UK after a week's training course a few miles outside Boston Mass. I have a Chimaera 4.0 here which requires 98 RON (98 octane) unleaded fuel - known as Super Unleaded in the UK. While I was in the US I saw three types of fuel:
Regular - 85 RON
Super - 87 RON
Supreme - 93 RON.
How do you lot run TVRs on this stuff? Additives? or are we talking about differing methods of calibrating octane ratings here?
Cheers.

[Englishman in LA]

Gasoline pumps typically post octane numbers as an average of two different values. Often you may see the octane rating quoted as (R+M)/2. One value is the research octane number (RON), which is determined with a test engine running at a low speed of 600 rpm. The other value is the motor octane number (MON), which is determined with a test engine running at a higher speed of 900 rpm. If, for example, a gasoline has an RON of 98 and a MON of 90, then the posted octane number would be the average of the two values or 94.

Octane rating in the US is (R+M)/2

(Taken from www.chemistry.about.com)

[wolosp]

Thanks for that explanation...though I recall the figures quoted on the pumps as RON, anyway I think that clears it up. Thanks again.