600 Ho Fusion Carb - Fuel

I used to always run premium, but this year after being forced to use regular a few times and not noticing any difference I now run regular all the time. Mine's the CFI though, so you might not have the same results.

For us folks still on "old sleds", we have an key switch that let's us select an ignition curve for regular or premium fuel. On the IQ's this is done automatically with the detonation sensor and a new "smarter" ignition controller. The difference in the two fuel settings is about 3-5 hp, and maybe 1 mpg. Most butts, mine included, can not tell the that 3-5 hp increase, but of course if you are racing on the clock, the clock can. Does it run better on 87, no, probably not. Will it run good on 87 or 93, yes.

I agree with Snofast - I have run both in mine and don't notice any difference in performance. I do notice a difference in mileage, and since my mileage already is terrible, I stick with the premium. 1 mpg might be the difference between making it to the gas station and walking.

I always burn premium, could be why I get the mileage I do. I did burn regular once, it didn't run as well (kinda bang-bang instead of steady purr).