My gasohol experiment

Did you really mean "percent". I get about 2.5 mpg better mileage with the summer gas over the winter. 2.6% is only .65 mpg.

I did. In absolute terms, the improvement was 0.7 MPG.

That is about right. Given that ethanol has about 2/3 the energy content of gasoline, having 10% ethanol should cause about a 3.3% loss in mileage which is close to what you had within experimental error.

A lot depends on how well the car can adapt to the ethanol. Some cars are better equipped to handle it than are others.

Matt

Hmmmm, the difference on my cars between summer and winter is much greater. Could be other additives factored in though.

Have to keep ADM fed and plump.

That is due to the "winter blend" that has a higher RVP and also due to the fact that the car loses more heat to the environment in the cold, has more friction due to cold oil, tires, etc., etc.

What really surprises me is the improvements they've made with AC and gas mileage. There's been studies showing cars actually get better gas mileage with AC on over just the windows open.

I remember a couple of cars with a big V-8 and you could feel the power drop when the AC was turned on. Today, I can't even tell if the compressor is engaged.

I rarely open the windows these days, preferring the quiet of no wind noise and the comfort of climate control. About four days a year I wish I had a convertible. Last time I drove one was a few years ago, it was a rental. I drove down Las Vegas Blvd with the top down and the AC full blast in the 100 degree afternoon.