I started a simple experiment a couple tanks of gas ago, to see what my truck gets for mileage, and what the differences are between E85 ethanol and gasoline.

It's not a terribly scientific experiment. If I was going to more scientifically perform the test, I'd clean out the tank and fuel systems, replacing the plugs and so forth. I just did the same thing that the bulk of us do; fill 'er up, divide the miles by the gallons it took to do that.

I started on October 13, after a summer of running E85. I'm doing it just 'cause; I don't have any particular "stick it to the oil company" or "it's cheaper" agenda. This summer in Minnesota, gasoline stuck around $2.85 for most of the summer, while I was able to fill up for a good fifty-cents a gallon less of E85. Results in a savings of about $10 a twenty-ish gallon tank. This tank cost $42.46, but the receipt doesn't have the fuel on it, just the charge. I noted 36,780.2 miles on the odometer. It's a digital odometer, so I can't even estimate how close to the tenths it was.

I drove normally, not trying to sway the calculations either way. I went the same routes, I visited the same places, and I drove with the same voracity wherever I went that I would normally. It was still warm enough to ride my motorcycle, so it took eleven days before I needed another fill. I waited until the "low fuel" light came on, and turned into the next gas station at my convenience.

On October 24 I put 20.623 gallons of gasoline in the tank. It's a 21.5 gallon tank, so pretty close to empty. Close enough for my experiment. The odometer reading noted on the receipt is 37,024.6 miles. I travelled 244.4 miles on the tank of gas (is that all?). Dividing the mileage by the fuel gives us 11.851 miles per gallon of ethanol. Not impressive at all.

On November 4 I filled up again, putting 19.660 gallons of gasoline in the tank. I switched to gasoline for the winter as the ethanol doesn't ride as nice, and it runs really rough when it first starts, if it first starts...sometimes it takes a few tries. The odometer reading noted on the receipt is 37,321.6 for an even 297 miles travelled. Again dividing the miles by the fuel, we've got 15.107 miles per gallon of gasoline. Much nicer.

For the whole experiment, 541.4 miles were travelled, using 40.283 gallons of fuel. The blend of fuels give us a combined average of 13.440 miles per gallon for these three weeks.