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Running E85

Discussion in 'Gen III 2010+ Prius Technical Discussion' started by WE0H, Feb 24, 2012.

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  1. WE0H

    WE0H ^^My garage queen^^

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    Anyone else tried a E85 blend in their 3rd Gen?

    I have been running different blends in my rental Prii for a couple thousand miles now with no lower mpg and no codes. It is costing less to fill the tank :) The last tank was 5 gallons E85 with 5 gallons 87 octane. Zero problems and the same mpg as straight 87 octane. Tonight I filled the tank with 6 gallons E85 with 4 gallons 87 octane and will run that out tomorrow. E85 is 60 cents cheeper in Indianapolis and 35 cents cheeper in Minnesota than 87 octane. I have a E85 converter for my own Prius when I buy it this spring but I wanted to get some experimenting done now so I know how the car runs on it bone stock. I've been running E85 blends in my SUV at home but this is my first chance trying it in a Prius. So far it runs flawless and is costing significantly less money to fill the tank :)

    Mike


    Sent from my iPhone :)
  2. wjtracy

    wjtracy Senior Member

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    ...very interesting but conflicts with conventional wisdom that ethanol reduces MPG.
    So therefore we must take this with a grain of salt unlesss you tell us more solid data. Need to know what MPG you are getting, and if this is manual calcs or read-out. Prefer manual calcs. Interesting about cheaper refill cost, but expectation is higher cost due to more frequent fill-ups needed.
  3. MrBillTulsa

    MrBillTulsa Member

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    :rolleyes:

    I was just thinkin', wjtracy.

    If your canoe had a painted snarly face on the front, like a P-51 during WWII, it would turn into a smile when it’s on the water.

    That would be nice to see!

    Just thinkin’, that’s all.


    :eek:
  4. cwerdna

    cwerdna Senior Member

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    Yep, Daily Fuel Gauge Report--national, state and local average prices for gasoline, diesel and E-85. lists MPG/BTU adjusted prices for E85.

    When CR tested a FFV Tahoe, they got 14 mpg overall on gasoline and 10 mpg overall on E85. See Test results: E85 vs. gasoline.

    Besides the Prius not being approved for E85, running it seems penny-wise, pound-foolish, IMHO.
  5. john1701a

    john1701a Prius Guru

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    It depends on the blend and the system using it.

    E15 & E20 studies here in Minnesota have actually shown an increase in efficiency over E10 for some newer vehicles.

    You still won't get a gain over pure dino-gas. But with the opportunities for ethanol creation coming from bio-waste and rollout of E100 vehicles in places like Brazil, there is hope on the clean & renewable front.
    .
    2 people like this.
  6. GrumpyCabbie

    GrumpyCabbie Senior Member

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    How far can the Prius engine management adjust for ethanol? I know Toyota don't recommend using anything beyond E10 (or is it E15) but is it technically possible for it to run on E30 or E50 blends without major issues? Or maybe it can run at E85 but Toyota just don't want to advertise this for warranty reasons.

    Will the engine compensate automatically? And if so, are there limits to how far this will go?

    One other thing. Brazil has lots of ethanol in their fuel and surely if the Prius is sold there it's either going to run happily or not not at all.
  7. tevogel

    tevogel Junior Member

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    i was told dont not use e85
  8. GrumpyCabbie

    GrumpyCabbie Senior Member

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    So was I, but I was asking can it, not should it.
  9. JamesBurke

    JamesBurke Active Member

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    Toyota will have 3 plants in Brazil soon. "Toyota Motor (TM) said Thursday it plans to spend $600 million to build a third plant in Sao Paulo, Brazil, where it will build a new small car."Toyota to Build $600M Plant in Brazil to Produce New Small Car - DailyFinance

    Vehicles produced for their local/reagonal market and are specifically designed for ethanol fuel. No imports or Hybrids there.

    You can use e85 if you want but like svo in a diesel how long till it breaks.
  10. DetPrius

    DetPrius Active Member

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    I believe fuel and valve seats are different on vehicles designed to run E85 so they can handle the E85 and not encounter long term problems. Testing it in a rental is a great idea, and another reason I would not buy a rental car. On a cross country trip late last year, I had the opportunity to run some pure gas instead of E10 and found a clear MPG improvement so it is hard to imagine E85 not taking an MPG hit over E10.
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  11. David Beale

    David Beale Senior Member

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    I still find it funny people would do things the owners manual specifically states NOT to do.
    Things like run fuel with more than 15% ethyl alcohol (E16 or greater).
    Things like running out of fuel.

    Adding a tow hitch and using it is one thing ("not recommended" says Toyota), but the above is something else entirely!

    Yup, the car will run. For how long you're going to find out. Hope you have lots of money!
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  12. WE0H

    WE0H ^^My garage queen^^

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    The reasons for me trying this experiment was I always got higher mpg in the rentals (Camry, Sienna, RAV4, Prius 2nd & 3rd Gen's, Sonata, & Elantra) when I filled up in Iowa with their 89 octane ethanol blend gas. So I have been running blends in my SUV at home and now this rental Prius :) I will wait until May or June when I get my '12 Prius to do a more accurate mpg study of gas verses my blends and finally with my E85 converter which BTW is EPA certified to run on US vehicles and will NOT void the manufacturers warranty. Do the research as I am on the road now and it's not easy for me to post links and such. John would know what I am talking about since he knew about the University of MN studies on running E85 in non-flex vehicles. Look up that and other studies before posting myths and Internet rumors ;) It took me a long while before I felt safe running it in my own SUV but now that I know it is not only safe for it but also providing less support to those crazy oil producing foreign countries with my use of made in America ethanol :) E85 also burns way cleaner than straight gasoline for less polution ;)

    Ok enough typing on my phone, John would you please keep the crew entertained while I drive home? I might be able to check in when I stop at rest areas. Got a 14 hour drive ahead of me today.

    Thanks a bunch,
    Mike :)


    Sent from my iPhone :)
  13. cyclopathic

    cyclopathic Senior Member

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    that and the long term exposure of plastic/rubber parts. It the past E85 enabled cars were using different but it may be no longer the case with E10 being a norm.

    Yes in close loop mode ECU will adjust mixture to compensate for E85, but when you accelerate ECU operates in open loop mode, the mixture will be too lean with foot on the floor. This may cause issues when engine operates under heavy load for extended period of time (mountain climb, heavy traffic in hot weather, etc)

    IIRC a decade ago Toyota ran tests and found that 20% or even 30% of ethanol would not be decremental to engine and MPG. But 30% is 3-3.5gal, so you maybe saving $2 per tank is it worth it?

    Another consideration b/c E85 is cheap Midwest, many gas stations running a scam (buying E85 and mixing it in E10), so depending on the station you may already have E20-25. I ran into this on a motorcycle trip (bike has an open loop system), and engine would overheat to the point I'd need to pull off. At the end I started to avoid no-name gas stations and the Phillips-Conoco selling 87 and E85. Pay a bit more but no issues on 85/86 they selling.
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  14. seilerts

    seilerts Battery Curmudgeon

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    Okay, so I can't speak for Gen III. If it is tuned for E10, rather than pure gas, then it is possible to run a fairly high blend of ethanol without codes.

    For Gen II, and just about any other non-flex-fuel vehicle, there have been definite problems. Somebody fills up solely on E85, and then gets P0171. Under the OBD II standard, if injector pulse width has to increase 20% higher than the standard fuel map, then the car will set P0171. This can happen if fuel pressure is too low (bad fuel pump) or fuel energy is too low (E85).

    But I know people who run E50 and it is fine. They also have a ScanGauge or other type of instantaneous monitor and watch their long term fuel trim. IIRC, E50 results in a LT fuel trim of +15%, which leaves some leeway. It also is higher octane, which can result in better performance/MPG, as it makes the knock sensor less likely to retard ignition timing under load.

    Anyone who runs higher than E10 should have some kind of scanner to monitor LT fuel trim, and be able to reset the check engine light in case of a fat finger at the ethanol pump.
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  15. xs650

    xs650 Senior Member

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    I've also been wondering about the materials issue. Some of those problems wouldn't show up for a couple of years or more. You may be right about the manufacturers going to fully compatible materials because of E10 and the potential for higher levels of E in the future, but I will let the experimenters find out for us.
  16. xs650

    xs650 Senior Member

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    Does the LT fuel trim also work when running open loop? That would be a good thing.
  17. john1701a

    john1701a Prius Guru

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    Wondering shouldn't be necessary.

    Both GM & Ford promised 50% of their fleet would be E85 capable by 2012. Remember that, back with the "Go Green, Live Yellow" craze?
    .
  18. xs650

    xs650 Senior Member

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    Assuming you take Ford and GM at their word....that still doesn't cover the other 50% of Ford or GM or any other manufacturer.
  19. WE0H

    WE0H ^^My garage queen^^

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    She's still running fine as I sit for lunch in Champaign IL :) Nasty NW winds blowing the car all over the Interstate :( This run would not be one to judge mpg as the car is loaded so heavy the tires are tucked in the wheel wells. Dont know how to upload a pic from my phone to show :(

    Mike
  20. GrumpyCabbie

    GrumpyCabbie Senior Member

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    If there's no pic, it didn't happen :)
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