E85. Which engines can run it, what is its combustibility and efficiency in comparison to diesel or gas?

Question

E85 is often cheaper than regular gasoline, but apart from knowing that it has to do with ethanol and is made from corn, I have no idea what it is. Will normal engines run it(is a conversion needed)? Is it very efficient concerning fuel mileage?

Answer 1

With E85, you will average about 20% less fuel efficiency than with gasoline.  So when you purchase E85, you need to buy it at least 20% less than the price of gasoline to break even.

To use E85, the vehicle must be setup as a Flex Fuel vehicle from the factory.  At one time, there were conversion kits for this.  The EPA had all of them pulled from the market because these conversion kits increased emissions too much.

If you attempt to use E85 in a vehicle that is not flex fuel capable, you risk doing some expensive damage to your fuel system.  The ethanol ion E85 is corrosive. Your fuel lines must be made of materials that can handle E85. E85 can deteriorate some plastics. The plastic parts in your fuel system must be able to handle E85. E85 can damage your fuel pump and fuel injectors. E85 has a higher oxygen content than gasoline.  This will cause your oxygen sensor to read out of range and cause a check engine light.  Flex fuel vehicles have an additional sensor in the fuel tank to read the ethanol content of the fuel. The engine management computer reads this and adjusts the fuel / air mixture and ignition timing accordingly.  Without this additional sensor, your engine can run so poorly that you lose any benefits of the reduced cost of the E85.

There is another minor maintenance issue seldom mentioned with flex fuel vehicles. After time, gasoline will build up a sludge in the fuel tank, fuel lines, and fuel injectors. The ethanol in E85 acts like a strong solvent.  It will clean all of this sludge from your fuel system.  This can plug your fuel filter.  If you haven’t used E85 in your flex fuel vehicle in a year or so, you may want to change your fuel filter after the first tank full.

As I said before, flex fuel vehicles get about 20% less fuel efficiency when running on E85.  I believe future models will do much better.  This is because E85 is not available in all areas so they tune these vehicles to run primarily on gasoline, but are capable of using E85.  When E85 is available every where, the auto manufacturers can change the way these engines are tuned.  They will change the engine compression ratio to take advantage of the 107 octane of E85. This will greatly improve combustion, fuel efficiency and power.  But when these vehicles are made, they will no longer be able to use gasoline because of its low octane rating.

For a complete list of vehicles that can use E85, see the link below.  The website also has a complete list of E85 refueling stations.

Answer 2

You can only run E85 in a "Flex-Fuel" vehicle.  The vehicles that can run E85 have "Flex-Fuel" marked all over them.  You can't run a "regular" gasoline engine on E85, and it's not a good idea to run a Diesel engine on it because it won't run worth a darn -- IF it runs at all.  In terms of fuel efficiency, it's about the same as a standard gasoline engine, depending on the manufacturer.  Like most cars, some E85 vehicles are more fuel-efficient than others.  The big problem with E85 is the whole world couldn't produce enough corn to satisfy the need for it in the U.S. alone if 80% or better of the vehicles here ran on E85.  That's why E85 is a temporary fix at best for the oil dependency problem.