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Can a Prius use E85?

Discussion in 'Gen II Prius Main Forum' started by Devilstower, Jun 16, 2005.

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  1. Devilstower

    Devilstower New Member

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    I've looked back through the E85 topics that have appeared before, and I've read the (somewhat chaotic) Creed Project report, but I haven't seen anything that looked definitive. Has anyone else tested this? Can a standard 2005 Prius really use E85 fuel without ill effect?

    This fuel has recently become more widely available in my area (Missouri), and it would great to think that I was not only getting better mileage in my Prius, but using only 15% oil-based fuel to do so.

    If a standard car would have trouble, are their well-known modifications that would allow this?

    Ultimately, I would love to be driving a plug-in version of the Prius burning E85 as my fuel. A vehicle like that would be a very light touch on the oil supply.
  2. galaxee

    galaxee mostly benevolent

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    My husband just borrowed a hybrid training book from one of his coworkers, a Prius Tech. That particular manual says E10 is the highest ethanol content that should be used.

    However. You could try it, and if problems arise play the "I didn't know" card when you take it to the dealer.

    I would definitely not advise actually doing this unless you have a lot of money to throw around on repairs...
  3. HYACK

    HYACK New Member

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    I think it's reversed? 15% of the fuel mix is derived from ethanol, 85% gas? Correct me if i'm wrong, however W Bush the other day was imploring the nation as a whole to transform (short/mid-term) to 15% ethanol and bio-diesels.

    Most if not all current US ICE autos can burn 15% ethanol w/o any mods. However, Brazilian autos are slightly modified I believe, to burn up to 25% bagasse-based ethanol.

    I don't think a standard US engine, Prius et al, can operate much over a 15% mix.
  4. Sev

    Sev New Member

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    E85 fuel is indeed 85% ethanol and 15% gasoline. It is rated at 105 octane. Check out this site: www.e85fuel.com/ I wish we would get a definitive answer as to whether the Prius can be specially tuned to use it. THe ethanol coalition does not list any Toyota vehicles as being able to use E85.
  5. Devilstower

    Devilstower New Member

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    Nope, E85 is 85% ethanol, 15% regular old gas (would you really be surprised if George got that backwards?).

    I'd hate to hurt my silver 2005 baby, but I'd love to think this would work. Too bad the pumps don't come in E15, E20, E25... so I could just keep going until I had a problem.
  6. naterprius

    naterprius Senior Member

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    You can make your own E20. Just mix a small amount of E85 with a large amount of Gasoline. Check to see if your gas is E10 or not to work out the numbers.

    I'm not recommending this for your Prius, though.

    Nate
  7. HYACK

    HYACK New Member

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    Interesting, and call me ignorant ;)

    Well, all I Know is that the 15% mix specifically promoted yesterday is pushing the avg 10% and sounds rather like a campaign point of Howard Dean's??

    Beyond that don't most current ICE's need engine modification?
  8. Devilstower

    Devilstower New Member

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    I'd mentioned the Creed Project earlier, but failed to provide a link.

    They took a 2003 and gradually increased the ethanol percentage until the vehicle was running on E85. While it seemed to operate fine, and got greater horsepower (though certainly less MPG, since ethanol has only about 70% the BTU value of gas), they made no long term tests.
  9. HYACK

    HYACK New Member

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    If 85% was mandated next week, nationwide, I'd like to see the corn futures market!
  10. tag

    tag Senior Member

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    Here's some information about E85 and FFVs:


    What are the differences in an FFV compared to a regular gasoline-only model? Are different parts used?

    Response:

    There is only one major additional part that is included on an FFV - the fuel sensor that detects the ethanol/gasoline ratio. A number of other parts on the FFV's fuel delivery system are modified so that they are ethanol compatible. The fuel tank, fuel lines, fuel injectors, computer system, anti-siphon device and dashboard gauges have been modified slightly. Alcohols are corrosive. Therefore, any part that comes in contact with the fuel has been upgraded to be tolerant to alcohol. Normally, these parts include a stainless steel fuel tank and Teflon-lined fuel hoses.

    LINK: http://www.e85fuel.com/e85101/faqs/diffferences.php

    What is E85?
    E85 is a blend of 85% ethanol and 15% unleaded gasoline for use in Flexible Fuel Vehicles (FFVs). E85 is classified as an Alternative Fuel by the U.S. Department of Energy.

    What is a Flexible Fuel Vehicle?
    A Flexible Fuel Vehicle (FFV) is a vehicle that can operate on any blend of ethanol up to 85%. If E85 is not available, the vehicle can operate on straight unleaded gasoline or any percentage of ethanol up to 85%.

    Many major automakers including DaimlerChrysler, Ford, General Motors, Mazda, Mercury, Isuzu, and Mercedes manufacture vehicles that can operate on E85. FFVs have been produced for several years, and the number of E85-compatible makes and models is increasing each year.

    LINK: http://www.ethanol.org/e85.html
  11. HYACK

    HYACK New Member

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    hmmm, stainless steel fuel tank?

    I would hope the bladder could accomodate 15%.
  12. tag

    tag Senior Member

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    Yeah, I would hope so as well. We have 10% in the Chicago-Milwaukee corridor. I'd like to think an extra 5% wouldn't screw things up too badly.
  13. DanMan32

    DanMan32 New Member

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    Dudes! E85 is 85% alcohol, not 15%. E10 is 10% alcohol. The E stands for Ethanol, so think Ethanol85 or Ethanol10

    Besides the tolerance of the fuel carriers (tank, lines, injectors) from damage by exposure to high ethanol concentration, there is also the issue of the ECM MAP.
    When you start a car, the car judges how much fuel to mix with air to run properly, with an edge of being a bit rich. It does this until the O2 sensor and cat are warmed up. Once they are warm, then the computer can adjust the fuel mixture for complete burn using the O2 for a closed loop feedback.
    However, the ECM also realizes that the deviation from the norm is so far out, even if the O2 says complete burn, that the ECM things something's wrong and triggers a CEL. This is what happend wtih the 2003 experiment.
    A FFV will have 2 MAP tables, one for E85, and one for E10/E00 and will switch between the two based on what fuel is used.
  14. naterprius

    naterprius Senior Member

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    Well said, Dan. The only correction is that the Ethanol percentage in the fuel is constantly changing since you don't empty the tank completely and then fill with E85 or E10 or E0. You fill the tank with any of the three at any point, like half full or quarter full or whatever, so the sensor and map must adjust on sliding scale for the amount of Ethanol anywhere between 0-85%.

    As far as E85 in a Prius, I'd worry more about the bladder, the seals, fuel pump (which lubricated only by the fuel) pressure regulator, and injectors more than setting a code (triggering the "Check Engine" light).

    The light can always be reset, and the tank filled with 100% gasoline if there was a problem during running, but the rest of those parts sound expensive.

    Nate
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