I have had my truck over a year now and am thrilled with it. I just last week for the heck of it put a whole tank (21.8 gallon fill) of E85 gas. My first time using E85 in any vehicle.

I was expecting worse gas mileage, but was surprised HOW BAD it was.

I get 17-18.5 in the city, 21-23 on the highway most of the time. I averaged 13.6 for the entire tank.

Performance was not as good either, which I was NOT expecting.

I am curious to know others experiences.

I went through it, filled back up with regular gas on Friday.

For what it's worth, I saved 22 cents per gallon, but I dont think the math works out for me actually saving any money using this crap...

 

That's odd - performance should have been BETTER.

Only 22 cents savings doesn't work out well.

 

I tried running E-85 in my 07 with a 5.4, I waited until I ran my third full tank in a row before I made my calculations and I suffered a 4 mpg loss. Even tho e-85 was 30 cents a gallon cheaper than 87 at the time, it still cost me more to run it.

I also noticed a slight drop in performance, and hard starting in cold weather.

IMO e-85 is only good as a cheap race fuel, or if your a tree hugger. Otherwise don't waste your money.

BTW gasoline and gas blends like e-10 and e-85, the lower the octane number the higher the btu output. In a perfect world, 87 will get better mileage than 93 and 93 will be better than e-85 which has an octane of around 105. So running a higher octane your engine has to use more fuel to get the same amount of work (hp) which makes for worse mileage. And unless you are tuned to take advantage of the higher octane, you will never see a performance increase and might actually notice a decrease. Also, the perfect (stoichiometric) air/fuel ratio of 100% pure gasoline is around 14.64 to 1 while 100% alcohol has a stoich of around 9 to 1 and as you increase the alky percentage mixed with gas the stoich goes down. Basically that means more fuel needed to get the same amount of work, and that translates into worse fuel mileage.

 

Why do you think performance would be better? I was expecting it to be about the same. Not significantly worse or better.

What motor do you have?

 

Performance should have been better because of the higher octane, if the tune (timing curve) is written to take advantage of the higher octane.