so the scooter that i imported from thailand requires a RON (research octane number) of 91...before checking out the details, i thought that i'd use 93 here

on a whim i checked out the rating system of thailand and it turns out that they, like most of the world, use only the RON to label their fuel, while we use the AKI (anti-knock index, which is what's on the pumps as R+M/2)

my understanding is that you can multiply RON by 0.95 to get, roughly, the AKI...in this case, that RON of 91 is actually an AKI of 86.45 (so we'll say 87)

so does this mean i've been running 93 when i could have been running 87? if I haven't had any knocks (would a 1-cylinder 110cc scooter knock, even?), have i done any damage to it? i've put a bit over 600 miles on it with 93

4/2/2010 1:19:23 PM

my rule of thumb chart of octane conversion

95 RON = 91 AKI
98 RON = 93 AKI
100 RON = 94ish AKI

anything below 95 RON is your normal shitgas, 87-89 AKI. this issue comes up a lot when you are dealing with Japan spec tuning issues on turbo cars. you'll see that most sports cars require 95 RON minimum when sold in a non US market.

i would say you should put 87 in this thing

[Edited on April 2, 2010 at 4:49 PM. Reason : .]

4/2/2010 4:48:48 PM

just run the cheapest shit that won't knock

4/2/2010 9:51:37 PM

^^ why do you call it "shitgas"? it actually seems to be giving me BETTER fuel economy

but yeah, so far 87 seems to be working just fine...bah, i could have been saving $0.20/gallon!

4/5/2010 9:58:25 AM