For US readers:
The pump octane (PON) listing we see at the gas station is the average of RON and MON numbers.
PON = (RON + MON) / 2
The UK uses RON (Research Octane Number) on their petrol pumps. MON (Motor Octane Test) is a number created from a different testing standard than RON. So for the UK's 98 octane, which has a MON of roughly 90, it would correspond to a PON of 94.
You can read more at:
http://www.btinternet.com/~madmole/R...RONMONPON.html
And, as long as we're talking about your favorite gas/petrol: I like Amoco (now BP) Ultimate @93PON.
Chip H.