I used to be a farmer, so I was all-in for the ethanol. Now, I wish it would go away.
I owned one of the first Flex-Fuel vehicles available (a 1998 Dodge Grand Caravan) to accept E85.
I have done multiple tests with my 1995 Jeep Grand Cherokee (5.2L V8) as well as my 98 DGC (3.3 V6).
In 2008/2009 I traveled a LOT (about 4000 miles/month) and traveled the same route over and over. I experimented with different fuels related to gas mileage, cost per mile, and butt-dyno HP.
Jeep:
I ran the experiment for a month. 2 weeks using mid-grade E10 and 2 weeks using Regular mid-grade non-ethanol. During this time, I put on about 4000 miles.
With E10:
Gas mileage averaged 13-15 MPG
HP Felt lower, acceleration not as responsive.
Break-even difference:
$0.13/gallon So, to get the same mileage, the E10 had to be at LEAST $0.13 per gallon LESS than non-E in order to BREAK EVEN based on gas mileage/cost per mile. Gas prices at the time were $2.85 - $3.15 per gallon.
With Non-E:
Gas mileage averaged 15-17 MPG
Van:
With E-85 (Smelled like vodka when standing next to it running)
Gas mileage averaged 12-14 MPG
Acceleration was very weak. (Kinda felt like a Land Cruiser going uphill...)
Break-even difference:
33% per gallon So, to get the same mileage, the E85 had to be at LEAST 33% per gallon LESS than non-E in order to BREAK EVEN based on gas mileage/cost per mile. The costs at E85 stations was all over the place, and very hard to find at the time, so this was the best reference based on mileage. If regular non-E gas was $3.00 per gallon, then I should pay any more than $2.00 per gallon for the E85, just to break even, and experience power loss the entire time.
With Non-E
Gas mileage averaged 18-21 MPG
I have a 59 Studebaker and it absolutely HATES anything with ethanol. It vapor locks, starts hard, and runs rough when using ANY ethanol product. We recently found a Speedway gas station in Indianapolis, IN that had 110 octane LEADED fuel. Man, the Stude was like Lightning McQueen for one tank! (but it was also $7.499 per gallon!!!) I will drive 5 miles extra to find a gas station with non-E for this car.
These days, if I have a choice between 87 octane non-E and 91 octane E10, I'll choose the 87 octane non-E, and pay $0.10-$0.13 per gallon MORE.
My Land Cruiser DEFINITELY likes the non-E more, but I typically run 89 Octane E10 because that is what is most readily available on my daily route.
The MTBE they add in the winter is another killer of gas mileage and HP in everything we drive here.
On the early rigs, it's significantly easier to pass the emissions test on winter fuel.