Originally Posted by Kieren
I cant believe you all have such shit fuel over there. I live in Australia and the lowest RON available here is 91 (containing 10% ethanol). i run 98 in my 2012 Focus which by the way dose contain injector cleaner as well as a heap of other crap. There is definatly a difference in power and fuel economy.
We're talking about (R+M)/2 ratings, not RON ratings.
91 RON is equivalent to 87 octane, 98 ron is equivalent to 94 octane (using the estimate from the link Roadworthy posted).
Another interesting quote from his link is, "Using a higher grade than is required will not usually increase performance. However, if the vehicle is equipped with knock sensors, as many late model vehicles are, a higher octane grade may enhance performance."
But congratulations on having better fuel.
If you want to learn more, read this: Changes in Gasoline - The Auto Technician's Guide to Spark Ignition Engine Fuel Quality