Running E85 in your vehicle (fuel, octane, mileage, engines)

[Deez Nuttz]

I hear when you run your car on E85 the gas mileage goes down....is there any truth to this?

http://www.e85fuel.com/e85101/flexfuelvehicles.php (broken link)

[studedude]

If you check the manufacturers web site most of them show about a 25% decrease in fuel mileage with E85. Alcohol needs to run richer than gasoline. It is an oxygenated fuel and will do engine damage if run too lean.

[cdelena]

It simply contains less energy than gasoline... a 30% drop im mileage is common so make sure you are paying 30% less than gaoline.

[Deez Nuttz]

Thanks I will definitely look into this.

[texdav]

Consumer reports test showed that in flex fuel vehicles they tested that E85 got a average of 27% lesss milagte frm a tank than regualker gasolihne. There are also reports of engines developing more intake carbon with E85.

[ucfjtm]

Unless your car is designed for E85 (Flex-fuel labeled), your car's ECU isn't going to know to increase fuel injector duty and Air/Fuel ratio properly for the different fuel. Since there's approximately 30% less energy in a gallon of E85 compared to gasoline (just like gasoline has less energy than a gallon of diesel), you'll need larger fuel injectors, higher flow fuel pump, and different ECU fuel maps to handle E85.

A bonus is that E85 is more detonation-resistant than even Premium 93 octane.. so more compression/boost can be used before knock is detected. However, do NOT put E85 in a car that isn't properly set up for it (either labeled with Flex-fuel or configured by an aftermarket shop).

[yo vanilla]

Even using gas with 10% ethanol content will lower your mileage. I've recorded a drop of 2mpg in 2 different cars vs 100% gasoline. But you don't save money on the price of 10% ethanol'd gas

[himain]

We didn't see a difference at all in our Avalanche. I actually think we did better on gas mileage.

[wankel7]

Originally Posted by himain

We didn't see a difference at all in our Avalanche. I actually think we did better on gas mileage.

Then you were doing something different in driving habits when you ran e85. Or you calculated something different in error.

It is fact that ethanol has less energy than 100 percent petrol.

[jimboburnsy]

Originally Posted by himain

We didn't see a difference at all in our Avalanche. I actually think we did better on gas mileage.

Were you driving up a mountain on the regular gas and down with the 10% ethanol? If not, check your math because it's wrong.