Will E85 gas give me the same mileage that regular 87 octane gas gives me? My motor is the 5 liter and can use flex fuel according to Ford.
The only way to really tell is to try it. As your driving habits might not meet someone else who responds . Frankly I would not use the stuff myself.
Edit : Using that thing called Google most of the sites I found say E85 will give you 15 to 25 percent less miles to the gallon.
Short answer, No. E85 has less energy per gallon and will give about 20% lower mpg’s.
1 Like
The fuel economy rating for that truck on gasoline is
15 city, 22 highway.
On E85;
11 city, 16 highway.
2 Likes
You won’t find many folks here that are fond of ethanol fuels. If you want to see if they work for you, that link that Nevada included will show you your cost per year on average. However, with ethanol fuels the national average is less meaningful since it varies greatly by price in different regions. Try doing the math to see if it makes sense for you given your local fuel prices. I’d like to know what you find.
E85 has about 30% less energy per gallon, so it’ll get about 30% fewer miles per gallon:
EPA regular gas: 15/22 mpg
-30% = 10.5/15.4 mpg
EPA E85: 11/16 mpg
Ain’t science great!
I have a buddy with a newer model GMC Denali Yukon. He’s fond of buying E15 gas, because “it’s so much cheaper.” But even he admits he can almost watch the gas gauge moving down as he drives.
Last time I was there I bought him a tank of “real” gas.
I’m not sure who actually benefits from ethanol in gas… but I’m pretty sure it’s not us consumers. 
2 Likes
You answered your own question. If, on E15, your friend gets, oh say, 5% less mpg’s but he pays 10% less at the pump, he’s ahead.
Except that he, and the rest of us, are also paying taxes which go toward ethanol subsidies. And he, and the rest of us, also have to deal with the damage that E-10 does to our older cars and our lawn equipment. And if you wanna get really petty, we’re also all dealing with extra road repairs from all the trucking of ethanol from the ethanol plant to the refinery. And also from the refinery to the ethanol plant, because they have to ship in gas to the plant so they can mix it with the ethanol in order to render it undrinkable, because otherwise they’re making moonshine without a distiller’s license. I am not making that up.
The money picture doesn’t begin and end at the gas pump.
I had a Flexfuel Plymouth Voyager and used E85 quite a few times. The van ran just fine but at lower MPG. The lower (subsidized) cost per gallon of E85 was not enough to make it as good a deal as the usual E10 or E15 regular gasoline. Premium (no ethanol) gasoline gave better MPG than anything else, but its higher price per gallon made it a poor deal, too.
I understand the deeper issue but most people make their decisions based on far shallower issues - what hits them in the wallet at fill-up time. ledhead’s friend isn’t thinking beyond what he pays to fill his tank at that second. He isn’t considering the poorer MPG’s, just what it cost him to fill the tank right then. Not the greater issues you’ve laid out.
If he thinks only a tiny bit beyond to his MPG’s, he needs math to calculate yea or nay. That is math beyond a great many people! 
E85 didn’t sell very well at all when first introduced when I was living in Ohio because it sold for essentially the same as regular gas. Didn’t take most people more than a tank or 2 to stop using it. Eventually the price dropped. Not sure if it dropped enough to be competitive with E10.
As for E15, some manufacturers are OK with that and have been for quite a while. Ford since 2013, GM earlier. Others at various model years say it is OK.
Given the easy availability and my octane needs, E10 premium fits the bill with an occasional dose of 98 octane E0.
I have a flex fuel vehicle that I bought used with a wheelchair lift. I would never use E-85 in it. I need it to run.
Very few gas stations in my area have E85 now, it has been years since I drained E85 from a customers car and poured into my own non E85 car, thank you for the free tank of fuel.
I can remember shopping for a car for my wife sometime around 2007-2008. The dealership salesman kept touting “this is a flex fuel vehicle”. Well that’s great. But we’re in Mississippi. And I’ve never seen E85 sold… I think I saw online there were a few places that sell E85 in Jackson. There may be more now, or maybe not. So the flex fuel option, at least at that time and in my area, was about as worthless as tits on a boar hog.
The availability of E85 has come and gone due to lack of sales. If one day there is a fuel crisis there will be millions of flex fuel vehicles on the road to take advantage of ethanol fuel, if there weren’t there would be public outcry as to why we have been deprived of alternate fuel vehicles.
1 Like
To my mind, this is somewhat like saying “if there’s ever a flu outbreak, there will be millions of euthanasia injections on offer.”
Ethanol, especially corn-based ethanol as we push heavily in the US, is never going to solve a fuel crisis. It might create one, but it’s not capable of solving it.
E85 gives you fewer miles per gallon, and when you do the calculation on the discount in price compared to E10 (what you call 87 octane gas), it’s almost never worth it.
I can think of a good reason to get a flex fuel vehicle where E85 isn’t available.
Every couple years, someone in the government considers raising the ethanol content in our fuel from 10% to 15%. People like the American Motorcyclist Association and antique car enthusiasts have managed to keep the government from doing this, but I fear it is likely to eventually happen, and when it does, those who have flex fuel vehicles will be better off than those of us who don’t.
Just like E85 isn’t worth the discount, ethanol-free fuel is disproportionately more expensive per mile than E10. For a while, I was using ethanol-free gas in my motorcycles, but when I sold the older air-cooled bike, I went back to E10 in the new one. I understand why boat owners use ethanol-free gas in their boat engines though.
As soon as E15 is generally available, they will start lobbying for E20.