A few days ago I pumped about 13.5 gallons into my 20 gallon tank so it was about 2/3 E85. The OEM onboard trip computer showed a drop of about 4 MPG. Just did some computing on my calculator and figured it cost us about 2 cents per mile more in fuel cost with E85. The E85 pump price was 20 cents per gallon less than regular unleaded at the same station. Also, by my calculations the E85 would have to be around 35 cents per gallon cheaper than reg unleaded to break even. And that was with about a third of a tank of reg unleaded mixed with the E85. With 100% E85 in the tank, it may require even more price difference to break even. I'm all for helping out with the oil situtation, but using E85 would cost me over $500 per year more in fuel for just this one vehicle. Not much of an economic incentive.