E10 fuel (10% ethanol)

Discussion in 'Gen 2 Prius Technical Discussion' started by R-P, Mar 6, 2020.

  1. R-P

    R-P Active Member

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    The European Union recently replaced 95RON petrol/gasoline with a maximum of 5% ethanol with one that has 10% ethanol (the switch from zero% to 5% was done quite some years ago).

    Discussion about the environmental merits (or problems) aside, how dangerous is this higher ethanol content for our Prii?

    It (Gen2 Prius) is on a list that should have no problems with E10, but there are loads of actual quantifyable problems with scooters*. If I understand correctly, especially the ability to draw moisture in that alcohol has, dries out rubber and many scooters that have been in a garage during winter, simply won't start anymore.

    If damage is that frequent and can that easily be linked to this new 'safe' fuel, wouldn't it be prudent to just switch to higher octane fuel which has a maximum of 5% ethanol (but in practise often still zero%...)?

    Can the Prius take advantage of 'better' fuel so it might get slightly more MPG with higher octane fuel?

    Before, I didn't think I would be better off with 98RON*** vs the standard 95RON***, but given that the energy density of ethanol is lower than that of petrol**, the MPG on E10 version of 95RON are supposedly worse than on the old E5 version of 95RON, so even regardless of potential damage, it might be economically sensible to switch to the more expensive 98RON. As the difference between MPG on 95 (worse now with E10) vs 98 (still the same) will have increased.

    But hard data is scarce... I put in my first half tank of this more expensive fuel, but since we're going towards the summer, the Prius is going to more efficient in the coming months anyway, so not too sure I will be able to prove (nor disprove) the effectiveness.

    Thoughts, links, etc. welcomed!







    * (anything below 50cc engine displacement is a seperate catagory which can be driven by 16 year olds with a special license, hence their popularity, bigger motorcycles/cars can be driven with a license when one is 18 (or little earlier when someone with a license is sitting next to you).

    ** I haven't read up on this, but is the energy density of ethanol lower or higher? It is said ethanol in petrol will worsen your MPG, but on the other hands, I seem to remember that a Königsegg (iirc, or some other hypercar) did like 900hp on petrol, but 1000hp on pure ethanol...


    ***
    98RON = 93 in the US
    95RON = 91 in the US

    Copied from here, some info on how the RON numbers compare to US numbers:

    Pump gas

    In the United States gas stations describe the types of gasoline based on the Pump Octane Number (PON). That number is the average between RON and MON. This causes many problems.

    If a fuel is 98 RON then it will be 93 PON -> 93 PUMP
    If a fuel is 95 RON and 87 MON then it will be 91 PON -> 91 PUMP

    Is American fuel quality bad after all?

    No, not at all. Contrary to popular belief, fuel quality in the States is as good as anywhere else in Europe. Most Americans think that because they are running 91 octane fuel, their engine will blow up. It is the same as if they were using European 95oct fuel.

    In our website you will find RON ratings required for each remap stage.
    98/100 RON means you will need to use 93 PON in the States.

    95 RON means you can use 91 PON in the States.

    Everywhere else in the world, 98 RON and 95 RON gasoline usually are fit.Anything lower then that and your modern engine will have a lot of trouble adjusting, even on the stock calibration.
     
    #1 R-P, Mar 6, 2020
    Last edited: Mar 6, 2020
  2. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    I find it hard to believe that Toyota used different plastics based on Ethanol content of fuel in the country of registration.

    My personal theory is that they used the same components no matter where the car was destined. The lack of trouble with US Prius in the last 15 years should be a hint that EU Prius with E10 will fare as well.
     
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  3. dig4dirt

    dig4dirt MoonGlow

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    I think you will be safe with the 10%

    I have not done any scientific studies (hehe) but the cost to upgrade in my neck of the woods to
    pure gasoline is not worth it for mpg, and surely isnt worth it in preventive damage to my Prius.
    Right now, 10% is $2.35 and pure is around $3 so a good 30% increase. makes no $en$e
    EDIT: actually pure is around $3.39 !!

    Now, I do use pure for my small engine gadgets, but that is mainly because I use a fuel stabil
    and purchase once a year and also sometimes forget to run them empty before winter.
     
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  4. valde3

    valde3 Senior Member

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    Fuels here have been like that sense 2011.
    95 RON E10
    98 RON E5

    Prius works fine with E10 and does not really benefit from higher (than 95 RON) octane. So use 95e10 unless you really just want numerically (slightly) better fuel economy.

    Toyotas really haven't had problems with E10 other than older direct injection gasoline ones.

    Most of even older Toyotas that aren't said to work even with E10 work fine with even lot higher ethanol content.
     
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  5. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    A minor reduction in MPG (and thus range per tankful) are the only practical effects of E10 fuel in a Prius.
     
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  6. fuzzy1

    fuzzy1 Senior Member

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    No. The Prius doesn't have a high compression engine, so it won't take advantage of the higher octane.

    Instead, MPG will drop slightly because E10 simply has a lower energy density that E5 and E0.
     
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  7. R-P

    R-P Active Member

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    Thanks. The difference isn't that big in price as it seems to be in the US (going by dig4dirt's numbers, like 40% more expensive???)

    There's a petrolbrand that has been selling the higher ethanol fuel ('better for the environment') for years and the price difference was 1 cent ( so e.g. 1.70euro for E5 and 1.69euro for E10). I never bothered, that's less than 1% in price difference for a fuel that will decrease your MPG by X%... Wonder what they are selling as the difference is still there when I pass them.

    But current situation is about 1.74 for 95 RON E10 and 1.82 for 98 RON E5 (but really E0 in most places). So difference is about 5%. I doubt I will win that back... but maybe I'll try a few more tanks of gas. As seen in my sig, I keep track of all my fill-ups including when E10 was introduced and when I put in 98.
     
  8. valde3

    valde3 Senior Member

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    Even if 98e5 is actually e0 and 95e10 is e10 energy content difference is less than 4% so 95e10 is still cheaper to run as Prius with its low actual compression doesn't really benefit from octane increase (from 95 RON).

    But is 98e5 actually e0? And 95e10 actually e10? To me that just wouldn't make sense. If regulation, taxation, prizing etc. would cause it to be cheaper to use more ethanol then the fuel company would use maximum amount of ethanol on both of them. If it would cheaper to have less ethanol then they would both have minimum amount on both of them.
     
  9. MickyMatter

    MickyMatter Active Member

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    I'm living in Germany and using E10 since I've bought my 2008 Prius in summer 2013. Of course I asked Toyota first, and they confirmed the compatibility.
    In this nearly seven years I drove about 108,000 km / 67,000 mi without any problems.

    "E10" doesn't contain strictly 10% ethanol, but 5% to 10% ethanol. So the difference can differ. And "E5" contains up to 5% ethanol. In fact both fuels could have the same amount of ethanol added.

    Depending of the way of drive the mileage with E10 can be better or worse.
    ADAC (Europe's largest automobile association) and DEKRA (world's 3rd largest vehicle inspection company) both are independently speaking of additional 1.5% fuel consumption, due to the lower energy of ethanol.
    DEKRA also is speaking of a possible better mileage, because of the higher octane rating of ethanol.
    I would say it depends on the driving. I assume there is a lower consumption with E10 in idle and driving with low power. While driving with high power there should be a slightly higher fuel consumption with E10.

    These days E10 is about 2.3% cheaper than E5. I'll continue to refill with E10!

    BTW: Mostly I'm driving with about 4.5 l/100 km / 52 mpg.

    SM-G950F ?
     
  10. MickyMatter

    MickyMatter Active Member

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    Yes, ethanol is cheaper. (At least in Europe or countries without oil.)


    SM-G950F ?
     
  11. RRxing

    RRxing Senior Member

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    Other than reallocating corn from food to fuel.
    Here my calculation of the practical effect of E10:
    Screen Shot 2020-03-06 at 10.59.16 PM.png
     
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  12. jhalfhide

    jhalfhide Junior Member

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    Bit of a thread revival here but the UK have just got their E10 at the pumps and I put in my first tank last night. Since then, the car is fine at city driving but the moment I take the revs up and join a motorway, I get constant P0138 errors.

    Will struggle through this tank and pop some premium in and see if the problem resolves, but it's a mighty coincidence

    LYA-L09 ?
     
  13. fuzzy1

    fuzzy1 Senior Member

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    If your fuel distribution supply chain has not handled ethanol blends previously, then the first batches through are likely to flush out whatever water had accumulated at the bottom of the tanks and pipes, initially causing problems for some customers. This particular trouble path should diminish quickly with later refills.
     
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  14. T1 Terry

    T1 Terry Active Member

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    Some might remember the old days when you added a bottle of metho to the tank of fuel to clean up the system, so even said it gave them better performance. Metho is a term used in Australia so no idea what term is used in the US.
    Anyway, metho is 100% ethanol, but the same people who said metho in the tank was a great idea, reckoned ethanol would wreck you engine and cancel your birthdays etc ... but these same people are glued to the TV when the Bathurst 1000 is on .... and these race cars run 85% ethanol and don't blow up even though they are pushed well beyond any limits the guy on the street would push their car.
    My 733,000 '08 Prius has run on E10 all its life, it isn't a happy camper when only regular fuel without the 10% ethanol is all that is available ....
    Ethanol coped much the same beat up hysteria as electric vehicles are coping now, it does bite into the fuel companies profits after all .....

    T1 Terry
     
  15. fuzzy1

    fuzzy1 Senior Member

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    All ethanol, not blended with methanol?
     
  16. burrito

    burrito Member

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    Apparently it just means "methylated spirits." Though the MSDS for Metho does list the ingredients as ethanol and methyl isobutyl ketone.

    It says that ingestion of Metho:
    ...though on another page it says:
    I'm not sure about that last one..
     
  17. dolj

    dolj Senior Member

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    Metho is Aussie slang for methylated spirits (the NZ equivalent slang is meths). Canada, Ireland, New Zealand, South Africa, and the United Kingdom also call it methylated spirits, but I believe it is known in the USA as denatured alcohol.

    The reason it is called 'methylated' spirits is that, while it is mostly ethanol, it is mixed with ~10% methanol (hence methylated). In addition, it is 'denatured' by adding isopropyl also alcohol, acetone, and methyl isobutyl ketone to the mix.

    These denaturing additives are primarily to discourage human consumption by making it bad-tasting, foul-smelling, and nauseating. Without these additives, the alcohol content could be as high as 99% and therefore cause blindness, brain damage, or be deadly if consumed.

    In NZ and Australia purple dye is added to make it more readily identifiable, but other regions may add blue or pink dye for the same reason.


    [burrito posted while I was typing up my post. LOL.]
     
    #17 dolj, Aug 27, 2021
    Last edited: Aug 27, 2021
  18. fuzzy1

    fuzzy1 Senior Member

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    Methanol does those too, from consuming significantly lower volumes than needed from ethanol.
     
  19. dolj

    dolj Senior Member

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    Correct seeing as it is also an alcohol. (I have edited that sentence slightly to make the point clearer.)
     
    #19 dolj, Aug 27, 2021
    Last edited: Aug 27, 2021
  20. meeder

    meeder Active Member

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    If it is caused by E10 fuel it will probably be a indication that something was wrong to begin with.
    The only engines that I have personally experienced issue with when running on E10 are downsized turbo engines like the Ford Ecoboost engines but those engines tend to run better on premium fuel anyway.
     
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