john hennessy wrote:
methanol is mixable with water so if you add 10% methanol to the gas, then you could add 2% water without separation.
Well, first, this is "Ethanol" not "Methanol". That extra carbon At-om (if I recall correctly) makes a helluva difference. For starters, ethanol is pretty much moonshine, won't burn your eyes and skin, doesn't melt pavement, etc etc. Methanol isn't missed one bit in the IndyCar garages. They now use E85 (prior to that it was E98).
Ethanol gets better mileage, but as I recall, not as much power, than methanol, and neither get near the mileage of gasoline. Back before 1964, some Indy cars ran gasoline, even though it produced less power, because they were trying to win the race on 1 pit stop (maybe less, if you believe the rumors). The 1964 Sachs/MacDonald crash prompted Indy to change the rules -- a 75 gallon tank limit and a mandatory 2 stops -- so that such gasoline wasn't used very much (last used in the turbine Lotuses in '68, and the use of gas instead of kerosine probably caused the bearing failures?).
Anyway, back to the subject at hand -- Pretty much everyone who has tried E85 will tell you that you'll get less mileage, to the point where costs will be a wash with gas. How much worse depends on the car's ECU I believe. Which goes to our suspicion that the original post's answer lies with finding out if someone is sneaking in extra ethanol....