Not sure how the 6 rates with the ethanol, all I know is that if you have a station with 85% ethanol I would jump on that like a fat kid on cake. At least in the summer months. Ethanol has just a slightly higher combustion tempature so on cold mornings you would have problems starting it. In Brazil, you have a choice of gasoling, diesel or ethonal. Major manufaturers have actually made cars down in Brazil to have an aux. gas tank to hold 2 gallons. What they did was on starting it used gasoline, and then to drive the car it used the ethanol. They pay on average .75/gal for it, where as gasoline is in the high $4 mark. If you ask me, the U.S. should stick it to the oil company and use the re-usable source of corn or sugar. All you need it the plants to process it. Of course we would need a lot of them to be able to supply ourselves. But in Brazil they pump out alot of ethanol each day. And viola`, our problems are solved (well at least at the gas pump!)Kwik trip started putting Ethanol in their fuel. Their REGULAR and PREMIUM were both the same price. Higher octane in the Premium for the same price. Couldn't figure it out, until i realized that the Premium had ethanol, and the regular didn't.
Also the E85 ethanol station had 10, 20, 85% ethanol fuels. The 10% was 89 Octane and was 5 cents cheaper than other gas stations with regular fuel, 87 octane.
So maybe it depends on the gas station. I know their is probably a law in Wisconsin that gives tax breaks to those stations that use ethanol in their fuel. Considering it burns cleaner, and is cheaper than gas, because we are in a corn producing state.
So they probably deduct state taxes on each gallon for ethanol, just to promote its use. But who knows.
I will just stick to picking the cheapest gas from now on, no matter the octane rating. Maybe i will do some tests to see which is better or worse.
btw.. some cars actually get better gas mileage using ethanol fuel, it depends on the make of your vehicle, no clue how the 6 rates...