There's a ton of corn grown up here which is why everyone is putting ethanol in their gas.
Gasoline producers are using ethanol primarily as an oxygenate to lower emissions... because MTBE was poisoning ground water due to leaking gas station storage tanks.
(Don't use E85 in anything but a Flex Fuel vehicle. The National Ethanol people won't be resposible for damage done to fuel systems in non-Flex Fuel vehicles from using too-high-concentrations of ethanol in gasoline.
Automakers are designing fuel systems to handle increasing amounts of ethanol, but at this point in the game, +/- 10% ethanol is fine; there's enough of a gasoline "buffer" to protect fuel system components...)I noticed when I went to the Palo Duro gathering that none of the gas stations had 91 octane, which is what my car calls for. In fact, all the grades were a point lower, IIRC.
Altitude.
BTW, don't use a higher octane gasoline than what your car manufacturer calls for. You are wasting money.
True that. Octane is merely resistance to pre-ignition. In other words, higher-octane fuel burns slower. Using higher octane than what your engine's compression and state of tune (now in software form!) calls for will only decrease performance, albeit almost imperceptibly.
One can use higher octane to a gain engine torque only when igniton timing is advanced.
There is the rare case where a person has used, say, 89 octane in his 87-octane-spec'd machine and noticed an increase in fuel mileage... now, that increase is possibly created by several factors (true "average" fuel economy figures should be determined by more than just one fill-up), but in this case the engine in question has been known by tuners to have an "over-anxious" spark knock sensor... and it could be that the 2 pts-higher octane created a combustion environment where the knock sensor remained somwhat quiet in it's communication with the PCM and ignition timing was never pulled (retarded) allowing slightly higher torque output and the result was a slight gain in economy.
But that's a rare scenario... and if that were the case across the board w/ that particular model odfcar, then the car should be spec'd to run on 89 instead.
