Conversion to E85 (Ethanol) - Material Damage?



I have a 2000 Subaru Outback and would like to convert it ( to run on E-85 (85% ethanol, 15% gasoline)

I found this statement in the CarTalk archives: “The materials in the car’s fuel system, including plastics and aluminum, need to be designed to handle ethanol. Some components, such as rubber o-rings and gaskets might wear out more quickly or suffer damage, if exposed to ethanol.”

Can anyone confirm/deny that? Thanks!


This is precisely the reason why only a limited number of vehicles can be operated on E85. Such vehicles are DESIGNED and BUILT to tolerate ethanol. I would not attempt to modify a vehicle for the sole purpose of using E85 instead of gasoline. If you really want to use E85, I suggest you buy a vehicle that has been designed to use it. A list of such vehicles is available at


Yes, I can confirm that. It’s true.

While I respect your commitment to the environment, you need not feel guilty for using gas. There’s considerable conroversy in the scientific community whteher the amount of fossil fuel used to produce and process the ethanol is really just as great as simply using gas directly to operate the car. There’s more politics than science in ethanol.


[b]Ethanol is very corrosive. This is why vehicles designed to run on E85 have what is called hardened fuel systems. This means the materials used in the fuel systems are designed to handle the corrosive nature of ethanol.

Also, flex-fuel vehicles have what is called a discriminator. The discriminator is able to detect the concentration of ethanol in the fuel. From this the computer is able to make adjustments to ignition timing and fuel delivery that allows the vehicle to operate on E85. So unless your vehicle is a flex-fuel vehicle, the computer in your vehicle isn’t capable of making those adjustments.

So, unless the vehicle is designed to operate on E85, it’s not a good idea to use it. Just ask my coworker who used it in his truck, and burned holes in the pistons.


 I would advice against it for the reasons suggested and because it is not likely to be an economically wise decisions.  Remember that with E85 you will get noticeably lower mileage. As more E85 is sold, the price will increase.  It has already reached that point.


Thanks to everyone for their input so far. My question is what are the differences between the “hardened fuel system” and the fuel system that’s already in my car? Does anyone have more details?

Re: Pricing - my local gas station in Colorado sells E-85 for 20% less than regular, so that should offset the mileage penalty.

Re: Environment - the majority of peer-reviewed studies found a reduction in greenhouse gases and other pollutants for ethanol vs. gasoline.

Re: Technical - I assume that the black box installed in the conversion process adjusts the injection times, etc, similiar to what Flexfuel Vehicle does.


take a look at and the FAQs there. It explains and comments on several of your concerns. To me, biggest issue is that there are no EPA certified or approved conversion kits. Buyer Beware.


If you buy E85 for 20% less than gasoline, it’s a break-even proposition at best, and what if the price of E85 goes UP?

There may be a reduction in greenhouse gases from a vehicle’s tailpipe using E85, but what about the energy expended to MAKE E85? So far, all the evidence I’ve seen is that it takes more energy to produce ethanol than you get out of it.

I still say, “If you want to burn E85, buy a car that has been designed for it.” In the long run this will cost less than trying to convert your current car.


Re: EPA Approval - The manufacturer states that their’s is the only “2007 OBD 2 Environmental Protection Agency (EPA) Compliant Ethanol Conversion Kit” available in the US.

Re: Rising E-85 prices ? I am more concerned about gasoline prices going up than ethanol.

Re: Environmental Benefits ? I think the scientific community (other than Patzek/Pimentel) agrees that ethanol provides environmental benefits, even considering the inputs used in its production. S. attached presentation from Michal Wang from the Argonne National Lab.


Re: Compliance - I talked to a guy at the EPA who clarified that there are NO certified conversion kits on the market in the US (certification is a pretty big effort). Some tests were done to show that emissions from converted vehicles are compliant with EPA standards, but that is only one piece that?s required for certification. So, legally, this is tampering with the emissions system, which is against EPA regulations.


Re: Pricing - my local gas station in Colorado sells E-85 for 20% less than regular, so that should offset the mileage penalty.

In addition to the other points about the price going up, and the price as current being a break-even situation, also consider that E85 is only as inexpensive as it is because of, among other things, a 51.5 cent-per-gallon federal blend tax credit. So 1) you’re shoving your personal cost off onto the tax payers, which will come back to bite you on April 15 once enough people follow your lead and use E85, and 2) that tax credit might just go away once the public finally figures out what a total scam ethanol is.

Re: Environment - the majority of peer-reviewed studies found a reduction in greenhouse gases and other pollutants for ethanol vs. gasoline.

And rather than shipping ethanol in pipelines like gasoline, they have to ship it by truck because ethanol absorbs too much water in a pipeline and becomes even more useless than it is now. So while you’re feeling good about yourself because fewer pollutants are coming out of your tailpipe (actually the carbon emissions are the same as gas), petroleum is still being burned (and therefore causing pollution) to plant, fertilize, harvest, process and transport E85.

E85, especially corn-derived E85 is a huge swindle being foisted on the public by farmers lobbies who are not satisfied with government crop subsidies, and are searching for ways to increase the price of their corn. And it’s working nicely. The price of food is up. The price of milk and meat is up (farm animals eat corn). The price of ethanol is up. The price of gas is up, in part because of all the different botique gas/ethanol blends that various states require. And the only ones profiting from this are the farmers and the oil companies. Joe Consumer is getting royally screwed, as is the environment.


Even if the price of E85 was an equal offset to the mileage loss, its still not worth it if youve gotta drive 20 miles out of your way to the nearest gas station more often.


This post hits the nail right on the head. Ethanol is a Farm policy issue, not an energy or environmental one. Its inefficient to produce and, though it may be marginally cleaner in the particulates department, there’s no reduction in CO2, which is what’s changing the climate.

E85 is supposed to address the issue of our dependance on foreign oil-- it does nothing to help the environment. Furthermore, I find the whole idea morally troubling. The basic idea is that because American farmers produce enormous surpluses every year, converting it to fuel makes sense. Currently, most of that surplus gets bought by the government and sent overseas to countries that don’t produce enough food. If ethanol catches on in a big way, farmers won’t have surpluses anymore, and you can guess what will happen to overseas agricultural aid. There’s already some issues with corn shortages in Mexico due to this very issue.

So I say keep running your subie on good old fossil fuels. Even if it did replace fossil fuels, it would only serve to prolong the carbon economy. If you really want to use bio-fuels, I say buy a bike and eat some corn-on-the-cob.