I have an 09 QC 4x4 with the 4.7. From what I have researched, they claim about 12% MPG loss and really no con's to speak of. Well, locally gas is $4.10 for 87 and $2.99 for E85. I'm thinking about trying a few tanks, and was wondering if anyone had any experience.

 

I used e85 in my 4.7 dakota a few times. It was nice because E85 has an octane rating of about 105, so I was able to use my superchips performance tune with it to get some more power. But there was a definite loss of mpg.

 

For that big of a price differential, you'd have to lose 25% of your mileage, before it would be a negative thing...... If you were getting 16, it would have to drop below 12 before you would be in the hole.

Power will also be down, as alcohol just doesn't have as much BTU per gallon.

 

12% is better than any real world tests I've seen. The number for E10 vs. 100% gas are usually about 5-8% worse and E85 tends to be more in the 20-30% lower than E10 and 30-35% lower than 100% gas.

Even the govt. EPA site lists a larger drop than 12% and claim 20-30% and they would be VERY E85 biased IMO.

From the EPA site:

In general, E85 reduces fuel economy and range by about 20-30 percent, meaning an FFV will travel fewer miles on a tank of E85 than on a tank of gasoline. This is because ethanol contains less energy than gasoline.

Here is the EPA website dealing with E85 for further reading:

http://www.epa.gov/otaq/renewablefuels/420f10010.htm

Edmunds recently ran a VERY extensive test on this and without reposting the whole article, here are the results:

The Final Score — Fuel Economy and Cost
After refueling we put the fuel amounts and the prices paid into a spreadsheet and compiled a clear, side-by-side comparison for both fuel consumption and cost. Remember, these results apply only to this vehicle and to the prices in effect during our 667-mile test.
Gas Result: From San Diego to Las Vegas and back, we used 36.5 gallons of regular gasoline and achieved an average fuel economy of 18.3 mpg.
Gas Cost: We spent $124.66 for gasoline for the trip. The average pump price was $3.42 per gallon.
E85 Result: From San Diego to Las Vegas and back we used 50 gallons of E85 and achieved an average fuel economy of 13.5 mpg.
E85 Cost: We spent $154.29 on E85 for the trip. The average pump price was $3.09 per gallon
Gas/E85 difference: The fuel economy of our Tahoe on E85, under these conditions, was 26.5 percent worse than it was when running on gas.


I know an awful lot of people with engines that are rated for E85 who live in states where it is commonly sold and NONE of them stayed with E85 very long...

 

We had a flex fuel mini van and we saw about 20% less milage from E85 vs E10. $4.10 vs $2.99, I'd run a few tanks and see how it works out for you. The price spread is around what you need to make up the difference.

 

ive seen them be all over the place some engines built to accept the e85 do pretty good on it and only lose lower than average and some much higher. even among the same make and model. try it it wont hurt anything if it isnt cost efficient go back to what you were using.