Coming home from Hybridfest, I got my best tank ever. All expressway driving!

In fact, for a brief leg, I was going over 85 MPH, and I still set a record tank. (Filling up on Monday, my by hand calculations confirmed it.) I had been speeding because on my way back, I was going to see the Tutankhamun exhibit in Chicago, at the Field Museum, and thought I was going to be late for my timed ticket. I then realized that I never changed the clock in my car, and was in fact, going to be over an hour early, and slowed back down.

Both going and coming were at Speedways, both were, as far as I could tell, the same "purity" gas. While it's entirely possible that I took advantage of the terrain, and has a nice slope back, it still seems unlikely, I had a phenomenal tank, any way you look at it.

So, I'm wondering, does MI have crappy gas?

 

I think you can get unreformulated gas outside of madison. It might be possible that where you get gas in MI might be reformulated with either ethanol (e10 gas) or that other chemical whos name I forgot.

 

The only place we have RFG in WI is in the Metro-Milwaukee area. Anywhere outside of the Milwaukee area (like Madison) will have better gas than you probably have if you fill up in a more urban/populated part of MI. We always fill up the hybrids two counties west of Milwaukee to get non-RFG and a significant MPG boost.

 

I can't speak specifically about WI vs. MI gas, but I can say that gas formulations are different for different parts of the country. However, i would have expected that WI and MI were pretty much the same. You might have had a shift in wind direction which would increase/decrease your mileage, depending on the direction you were going. Plus, all other things being equal, you will see lower gas mileage the higher the percent Ethanol is (Ethanol has 30% less energy per gallon, so a gallon of gas with 10% Ethanol should deliver roughly 3% lower mileage -- 30% x 10% = 3% -- than straight gasoline). Also, your weight might have been different. Could be a few other varying factors in there as well.