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told not to use anything but regular gas..... true?

Discussion in 'Gen 3 Prius Fuel Economy' started by k.s.c, Mar 25, 2012.

  1. retired4999

    retired4999 Prius driver since 2005

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    Thanks, Mike :)
     
  2. WE0H

    WE0H Senior Member

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    Wonder if the new gas will someday be called G90 and G85? ;)

    Mike
     
  3. retired4999

    retired4999 Prius driver since 2005

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    :rolleyes:
     
  4. WE0H

    WE0H Senior Member

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    I still think it would be fun to build a still and make some E100 for vehicles setup to run on 'shine :) Might also be useful deicer for homebrew windshield squirter juice.

    Mike [​IMG]
     
  5. retired4999

    retired4999 Prius driver since 2005

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    And teeth cleaner! :whistle:
     
  6. WE0H

    WE0H Senior Member

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    Like Listerine :)

    A few years ago I ran my gas mower on E100. It kind'a smelled sweet and ran flawless.

    Mike [​IMG]
     
  7. john1701a

    john1701a Prius Guru

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    It's been around for years and has always been called E15.

    It and E20 have been through extensive studies, helping to confirm the upcoming E15 mandate here is an appropriate next step that won't cause harm to vehicles. Interestingly, the efficiency influence from the extra 5% is very small with some vehicles; it's not linear.

    Anywho, automakers taking the stance of not endorsing it isn't surprising. Liability issues are very complicated. Just look at the mess with EPA estimates.
     
  8. Ridder

    Ridder Member

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    Here, from 2010 on there has to be 5.75% ethanol blended in.
    From 2020 on it has to be 10%.

    But that % is not in volume, but in energy content.
    Ethanol has a lower energy content per volume than gasoline: there's already 8.5% vol in gasoline now and it wil be close to 15% in 2020.

    In Germany and France there's also E10 available and they have a list with cars that can't handle E10.
    The Prius is not on that list, only the 2 liter and 2.4 liter (1az-fse and 2az-fse engines).

    I do not know about E15 though.....
     
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  9. MadeleineR

    MadeleineR New Member

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    Thank you for the info from your Oregon vs. Carson City gas purchase... we drive around the NW a great deal, and it really is helpful to get your input. So, now days do you only use "regular" in your Prius?
    Best,
    Madeleine
     
  10. orenji

    orenji Senior Member

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    I run only Premium gas since day one, no issues with it, and in high heat as we are having now, it helps with preignition, incase the knock sensor is failing. The manual states use 87 or higher octane.......
     
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  11. AzWxGuy

    AzWxGuy Weather Guy

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    I guess it all depends on what a person is willing to spend on fuel. Many threads on this topic, some thinking that "premium" higher octane fuel might somehow be better for their engine and result in better performance. It just might be true for the Prius ICE considering the high (13:1) compression ratio, but maybe some other factors like the Atkinson cycle negate that. Here in Arizona there is a 10 cent difference between regular, mid-grade, and the high-test. Personally, I would like to run a tank of non-ethanol for a change and see how that works. We have year-round E10. When will the government give up on this bad idea?
     
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  12. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    It was back in the Gen 2 days when the manual warned against premium, I am sure that the modern engines accept it just fine, for those owners willing to waste money.

    There is no evidence that it helps anything in a Prius, however. Despite many "I just know it HAS to be better" posts, no one ever comes back with MPG charts or dyno charts showing any difference. 'Premium' has not had more detergents than regular in the US since 1995, before the Prius was ever sold.
     
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  13. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Minor point:
    • compression stroke is ~8.5:1 - due to the delayed closing of the intake valve, part of the fuel-air charge is pushed back into the intake manifold for the intake stroke. This makes regular gas possible.
    • expansion ratio is ~13:1 - this extended expansion stroke gives the near diesel like thermal dynamic efficiency while avoiding the NOx emissions.
    I did a fuel energy study before E10 became the norm in our area and some brands of regular gas had measurably more energy than others. But universally, premium ranked with the lower energy, regular brands. I can't replicate the study because E10 is not added at a precise ratio.

    BTW, I was able to see a slight efficiency gain with high octane gas climbing an 8% grade at full power. But it was not enough to be worth the extra cost in my area.

    Bob Wilson
     
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  14. qdllc

    qdllc Senior Member

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    Hell, I have a motorcycle with high-compression motor. I run REGULAR on trips. A guy I know who does GP racing told me that all the octane did was help with "knocking" and (off the track) really didn't offer that much of an advantage to make it necessary. More so, if you let a tank sit, the octane level drops over time. It's a very small part of the makeup of gasoline.
     
  15. LDB

    LDB Member

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    In a prior lifetime one of my clients was an engineer for Texaco. He told me the only reason to use a higher grade fuel was to prevent/eliminate knock and ping. At that time, about 20 years ago, he told me that while some brands did things differently Texaco put the same amount of detergent etc. in all 3 grades, the amount for premium fuel. Their only difference was octane. He said lesser brands used less as fuel grade went down and it amounted to about half a cent per grade so they saved about a penny a gallon on regular compared to Texaco. He also said the actual difference was about 2 cents per step versus the dime per step they charged at the pump at that time. He said use the lowest grade that runs well without knock/ping and save my money. I've followed that advice ever since. I'll use regular in my 3, especially now that it's way more than a dime a step. YMMV.
     
  16. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    Since a 1995 mandating the amount of detergents in gasoline, that is true of all oil companies. But you are right, it may have only been true of some oil companies before that.
     
  17. Okinawa

    Okinawa Senior Member

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    Your wife is right. Use regular. Anything else and you are wasting your money.
     
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  18. DoubleDAZ

    DoubleDAZ Senior Member

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    I could be wrong, but I think they only mandated minimum levels of detergents and I read an article that says many manufacturers actually reduced the amount of detergents because the minimums were lower and cheaper, hence the development of Top Tier gasoline. I don't know if this is a self-serving article or not, but I use Costco regular unleaded because it's cheaper and covenient. :)
     
  19. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    Top Tier also requires all grades by a given manufacturer to have the same level of detergent.
     
  20. DoubleDAZ

    DoubleDAZ Senior Member

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    That I knew, but I guess the actual chemicals can vary by manufacturer. :)