91 ron?
95 RON, 91 AKI (r+m)/2
91 ron?
My car is custom tuned and needs to run on 91 due to spark and timing adjustments.
Extra range with regular or premium? What car/engine? Technically regular has more energy in it than premium. If you are getting better range from premium your ECU is playing around with fueling and/or timing. Interesting to see you get that big of a difference.
Is there a 94 map available for your car? I can tell the difference with mine, especially in the hot summer months where the ECU will pull timing on 91 with the higher IAT's.
I think there are some engines that can sense what octae level fuel you are burning and adjust things like timing to take advantage of the different fuels. This may also explain why some cars do better mileage on different octanes.