Rassel

It was asked in another thread, but I didn't wanna go off-topic.

Here we go:

PON (Pump Octane Number)

RON (Research Octane Number) The knock resistance of the fuel in the CFR test engine is determined without preheating at 600 rpm. If the RON is too low, acceleration knocks occur (these are usually audible).

MON (Motor Octane Number) This determines the knock resistance of the fuel in the CFR test engine with preheating at 900 rpm. lf the MON is too low, high speed knocks occur (these are particularly dangerous, as they are usually inaudible because the engine is too loud!).

TON (Metric Unit for weight). A 993TT weights 1.502 ton and it has nothing to do with octane.

SON (Street Octane Number). This determines the knock resistance of the fuel in a series production engine. The SON specifies the octane rating requirement of the vehicle.

Euro = RON
US = PON = (RON + MON)/2

Here is a conversion table I ripped from a site:
RON MON PON
90 ... 83 .. 86.5
92 ... 85 .. 88.5
95 ... 87 .. 91
96 ... 88 .. 92
98 ... 90 .. 94
100 . 91.5 95.8
105 . 95 .. 100
110 . 99 .. 104.5

Fore those more interested I recommend to learn about Fluidized Catalytic Cracking.

Here is a link for starters:
http://www.refiningonline.com/Engelh...ep/TCR4_29.htm

Cheers