My wife's '07 is a flexfuel and since E85 is $.90 cheaper than regular gas here we decided to start using some because even with the drop in mileage, we're still saving money. my question is, will there be any long term negative effects by running alot of E85 through the truck? I'm aware of fords requirement to change the oil every 3K, which I do anyway, and that you need to run a tankful of regular gas through the truck every 3K if E85 is used 50% or more. If heavy use of E85 will damage the motor in the long run, it's not worth the money we save now.

 

Are you positive your actually saving money?

Yes E85 is cheaper, but it's BTU's per unit are much lower than unleaded gas. That means you will burn through more E85 when compared to unleaded gas.

Simple equation:

Just as an example, let's say your truck uses 100,000 BTU's to travel 15 miles.
For ease of calculating let's say one gallon of E85 is equivalant to 50,000 BTU's and one gallon of unleaded gas is equivalant to 100,000 BTU's. You will use twice the E85.

Obviously if your truck is designed to run on E85, why in the world would it wreck your engine? I just don't believe the $$ savings.

IMO

 

here's the figures I come up with. right now we're getting 15mpg on regular gas with short trips(15miles or less). I've been told by a friend that he was getting 12mpg with his identical truck on E85.

E85= $1.47gal
89 octane= $2.37gal

say you figure off 1000miles
E85- 1000/12mpg=83.3gal x $1.47gal = $122.45/ 1000=$ .12 per mile
89octane- 1000/15mpg=66.6gal x $2.37gal = $157.84/1000=$ .16 per mile

So you'd save $.04 per mile by running E85 if it stayed $.90 cheaper than regular, and if you run E85 for 10,000 miles it would add up to: 10000miles x $.04 = $400.00 saved. I know the prices won't stay the same but from my figure you need at least a $.49 per gal savings with E85 compaired to regular gas to offset the drop in mpg E85 causes, and that would figure out to only $12.40 saved over a 10000 mile period. But, at the current difference the money saved would be well worth it if no long term damage will happen. I know the motor is designed to run on E85, but that doesn't mean there won't be any negative long term effects because of it. Take diesel for example, all the new motoers are designed to run on ULSD fuel, but tests have proven that ULSD diesel has less lubricity than the older high sulfer fuel and thus causes more wear, even in the motors desinged for them.

 

Thanks for the calculations! I must say I am a bit suprised at your results, but you cannot argue against data.

 

If you stay off the throttle, you'll get better than 12 on E85. I typically get 14 on E85 and 17 on 91 in the city. That's according to my Edge. My truck puter shows 15.9 on gas and 13.8 on E85. there's a website E85 Prices that shows locations and price spreads. they also have a calculator Mine's a flex fuel also. Make sure you read the book about switching back and forth though...Full tanks only, and make sure you run some gas now and then. The book tells you all that stuff.

 

The biggest problem with E85 is that it's much more reactive than gasoline, thus it's much harder on the sealing surfaces in your fuel system, such as gaskets and o-rings. This is why you're NEVER supposed to run E85 in anything not built for it.

Your flex-fuel 5.4 is made to run on the stuff...most of the fuel system is made of different materials to handle it, and it should stand up to E85 just fine.

If you save money, it's certainly worth using!

 

Fordman, why do you use 89 octane? Do you have a tuner? if not the truck is set up for 87 and anything higher than that is just a waste of money IMHO.

 

if you get 12 mpg city on E-85 you are lucky

I got 10 mpg city and about 14 mpg highway with that Fecal Matter...versus 12-13 city, and 18+ highway on 87 octane.


For me, the math didn't work out so nicely. I barely broke even running E-85, and I was filling up my gas tank alot more often. Almost twice the normal rate.



Yeah, you save a few bucks on the front end...but long term I saw ZERO savings. I personally would rather run 87 octane and get a longer tank range, than use the E-85 and have the much shorter tank range

 

442W30, no I don't have a tuner, but here in IA 89 octane is always a little cheaper than 87 and I've never noticed any big difference in mileage between the two so I just run 89.

 

Yup, jives with my old numbers:https://www.ford-trucks.com/forums/6...g-results.html

I figured that E85 would have to be about .85 cents cheaper than unleaded just to break even. It's good you can get that price differential where you are. I've got an E85 pump right around the corner from my house, but it's only 20 cents cheaper = not worth the bad gas mileage.

 

I ran the numbers sometime ago as well, I get about 12 on 87 and 9 to 10 or so, been awhile, on E85. I came to the conclusion that it’d have to be around 90 cents cheaper for me to break even, but I run my truck a lot harder then some so I encourage you to do your own experimentation as everyone has different driving styles and conditions.

 

I have to agree with Tylus! I had the same experience, and will not use E85! It is a waste of time and not saving any money! Plus if you save some money on the gas, you now waste it on more frequent oil changes!