What octane of gas do you use in your Prime ?

Discussion in 'Prime Fuel Economy & EV Range' started by GKL, Jun 15, 2020.

  1. GKL

    GKL Active Member

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    I just read in the manual and it says on page 720:

    unleaded gasoline only

    octane rating: 87 (research octane rating 91) or higher

    We have not yet had to get gas for our new Prime, and hopefully it will be a while :D but I was wondering what octane most Prime owners use.

    We have gotten the lowest (and cheapest) octane for our cars, (I think it is 89 but it could be 87) as I have read in the past that using the higher octanes does not make a significant difference over the lower octane gas.

    According to the manual even 87 is okay to use.

    (Not sure why they say "research octane rating 91")
     
  2. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    The the US and Canada, we use a weird Octane rating called AKI. Most of the world uses Research Octane Numbers (RON) but some of the world uses Motor Octane Numbers (MON)

    Just to make life challenging, the US, Brazil, and Canada use AKI which is (RON + MON) / 2 or the average of RON and MON. I bet some government bureaucrat got a raise for that.

    Octane rating - Wikipedia

    87 is fine. But in general, use what is recommended in the owner's manual, any where in the world. Toyota's recommendations will change with local conditions. (Especially lubricants)
     
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  3. schja01

    schja01 One of very few in Chicagoland

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    As often as I put gas in mine I've been using Premium.
    Probably costs me $5/yr more to do that.
    I figure the car will repay me some day.
     
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  4. GKL

    GKL Active Member

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    Okay, thanks, yeah, they should keep things simple :rolleyes:, I'm guessing the manual we got refers to the rating system we use in the U.S., anyhow the manual says 87 and up is okay, so we'll just use the lowest octane like we have been with our other vehicles, I haven't focused on the octane rating of the lowest, I just pick the lowest one which is on the far left, I'll have to look at the rating next time to refresh my memory, the lowest is at least 87 but it might be 89, not sure, but I'll look to see next time we get gas in any of our vehicles,
     
  5. GKL

    GKL Active Member

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    Thanks, that is a valid point, the average Prime owner might get gas as seldom as 2-3 times a year so it's not a major difference over time.

    I'll keep it in mind, maybe do more research as it's been a while since I researched it, but I remember reading in the past that the octane rating does not make a really big difference overall.
     
  6. Mendel Leisk

    Mendel Leisk Senior Member

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    North American Owner's Manual gas specifications are always confounding. I gave up trying to make sense of it about 40 years back. It makes my head spin; @JimboPalmer seems to have nailed it though.

    All I cling to: every car we've ever had, and most every car on the road, is fine with regular. And with computerized ignition timing and fuel injection, even the cars that do specify mid or high octane gas can adjust (if needed), if regular is used.

    Which begs the question, and I really don't want top open that can of worms (or do I...): why do all the octanes get equal billing at gas stations?

    https://www.cbc.ca/marketplace/m_episodes/2012-2013/pump-fiction
     
    #6 Mendel Leisk, Jun 15, 2020
    Last edited: Jun 15, 2020
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  7. sam spade 2

    sam spade 2 Senior Member

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    Because some parts of the world use a different "system" to measure exactly the same thing......and come up with different numbers.

    And yes, it is perfectly fine to use whatever is considered "regular" wherever you live.
    Premium is just a waste of money.
     
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  8. sam spade 2

    sam spade 2 Senior Member

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    You figure wrong.
    Higher octane than you need can sometimes result in less power and a higher rate of carbon accumulation.
    In addition, if you buy that high octane gas from a station that doesn't sell a lot of it.......you may be getting gas that already is a LOT older than you might think.

    But if it somehow makes you feel better...............:)
     
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  9. GKL

    GKL Active Member

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    Good point, maybe the higher octane was a bigger factor back in the days of non-computerized cars.

    It would be interesting to see what percentage of gas sales are regular compared to the higher octanes, I would be surprised if regular didn't have a much much greater percentage of sales.

    Okay, sounds good to me, I'm glad to be able to stick with regular ! :D
     
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  10. schja01

    schja01 One of very few in Chicagoland

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    Probably not valid any more but at one time Premium had more/better additives which are a separate thing from octane.
    Also my cousin who worked for Amoco said said they dispose of reclaimed fuel by adding to to the storage tanks of Regular grade gasoline. Probably measured in parts per million but that tidbit stuck in my brain.
     
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  11. schja01

    schja01 One of very few in Chicagoland

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    It does. I go to stations that draw Lexus(es) as they should burn premium according to the owners manual.
    By the time the gas is actually burnt in my car is will be another six months old on top of the week or ten it spent in the distribution network.
     
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  12. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    Regular is high volume, economy of scale
    Premium is high profit margin, charge idiots all they will stand.
    There is no middle octane tank, they just mix them in the middle pump.
     
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  13. GKL

    GKL Active Member

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    Interesting, and I can appreciate your concern, since many Prime owners might only get gas 2-3 times a year has there been any reported problems of regular gas getting old and causing any problems in the Prime ?

    I would think (at least hope) that Toyota took that factor into account when they said using anything from 87 octane and up was okay, and would at least have a warning or caution about how old the gas can get before at least topping it off to refresh it.

    …….good points, helps me look at all possibilities :D
     
  14. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    The US EPA required detergents in all gas in 1995. Some auto makers thought he standard was too low and started the idea of Top Tier Gas in 2004.

    If you use Top Tier gas all grades have the same detergents, the gas station has to use weasel words like "No Gasoline offers better cleaning" as they are all the same.

    All non top tier gas has to meet the EPA standard.

    Top Tier Detergent Gasoline - Wikipedia

    I have no idea about other countries.
     
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  15. Salamander_King

    Salamander_King Senior Member

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    Regular unleaded octane rating (87) is all it needs. I have never tried using anything else on my PRIME, yet my lawnmower gets high octane (91) premium gas.
     
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  16. GKL

    GKL Active Member

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    We'll use the regular gas whenever our new Prime might need more (dealership started us off with a full tank)

    As far as our lawnmowers, our push power mower we use regular (maybe the premium might be better for it now that you mention it, I recently had to get a can of carburetor cleaner spray to get it going)

    Our riding lawn tractor needs non-ethanol gas only, more expensive, but that's what the manual says to use and I definitely want to avoid repair issues with that.
     
  17. Salamander_King

    Salamander_King Senior Member

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    The reason I use Premium gas for our lawnmower is not so much about octane rating, but in our local, the ethanol-free gas is only available in the Premium grade. And, in addition I even use gas stabilizer with it for all of my small engine power tools.
     
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  18. fuzzy1

    fuzzy1 Senior Member

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    I had understood that this varies. Some stations mix their own at the pump, some have it delivered to a separate storage tank.

    A bit of searching found the storage tank filler cap color codes. So if asking about any particular station, look at the colors of the underground tank caps:

    upload_2020-6-15_11-39-19.png

    There are some other charts available with even more color codes.
     
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  19. Tideland Prius

    Tideland Prius Moderator of the North
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    Given how long the fuel sits in our gas tanks, I debated using 91 AKI because it’s ethanol-free. 87 here is “up to” 10% ethanol. However, the price of 91 here used to be 10¢/litre more than 87 but has since risen to nearly 25¢/litre more so I usually just pump 91 when I’m in the US (it’s 15¢/gal more than regular). I’ve only pumped once in Canada and that was in March to take advantage of the low prices when they bottomed out and obviously the borders were closed.
     
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  20. m8547

    m8547 Senior Member

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    I use 85 octane exclusively in Colorado. Thats what they sell as regular. The higher altitude means there's less oxygen available to the engine (about 15% less at 5,000 feet), so less horsepower is reduced, and lower octane can be used. That applies to naturally aspirated engines. Turbocharged engines might be able to compensate for the lower air pressure and probably need to stick with what the owners manual recommends.

    I've never had a problem using 85 octane here, but I have had problems using it at lower elevations. One time I filled up my Honda Civic with 85.5 in South Dakota, assuming that if it was for sale it must be just slightly lower elevation than Colorado. But it was actually around 1,000 feet, and as a result the car was severely lacking in power and got around 22 mpg on the highway for that tank.
     
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