in australialand, we get 91, 95 and 98. also some e10s and e85s but they aren't really sold in my state.



most economy cars are sold for use with 91/e10. all of the euro cars andsome performance cars that make it here require mid grade 95. enthusiasts/highly tuned cars use 98.

 

Once again, other countries calculate the octane ratings differently. What you see on the pump is not directly comparable to what we see on the pump.

 

this is true. isn't it RON vs MON ratings? I think america uses another system again, or an average of the two readings. Australia uses RON, and i think japan does too. grey imports need to be re-tuned on arrival as they are tuned for 100 RON nip fuel.

 

Many imported cars sold in the US that require "premium" fuel are tuned for 93 R+M/2 gas. As a result, they make less power in west coast states that use 91 octane. A bone-stock EVO 8, 9 or 10 will make 20 more whp in Vegas by just mixing a few gallons of 100 octane in with a tank of 91. Same goes for the Nissan 350Z.