87 octane only fuel allowed?

Discussion in 'Prime Fuel Economy & EV Range' started by IABoy987, Jun 26, 2020.

  1. Gokhan

    Gokhan Senior Member

    Joined:
    Oct 5, 2008
    1,273
    603
    0
    Location:
    Paramount CA
    Vehicle:
    2021 Prius Prime
    Model:
    Limited
    Going over 87 octane has no benefits; so, don't waste your money. I verified that by experimenting with 91 octane for one tank.

    Avoid gasoline with more than 10% ethanol, and definitely 15% is the Toyota-allowed limit. The lower the ethanol is the better for the engine and mpg, but over here its all E10 (10% ethanol) gasoline as far as I know.
     
    douglasjre likes this.
  2. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    14,614
    10,269
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    Something I remember (at least, around 25 years ago this was a thing) was that some brands would in fact skimp on the detergents and other beneficial additives in their lower-octane blends, so their "premium" would have real advantages, not just the octane difference. There were other brands that did not skimp, and even their 87 would have the same additive package. Back in the day, Consumer Reports listed which brands those were, so you could buy your 87 from them. (I remember Phillips 66 was one of those on the list, and I used to buy from them pretty exclusively, but then they all left my local area.)

    There's a good chance that could all be ancient history now. I think that was before the whole Top Tier designation, which probably levels the playing field more, at least among the brands with the Top Tier check.
     
  3. fuzzy1

    fuzzy1 Senior Member

    Joined:
    Feb 26, 2009
    15,315
    8,607
    90
    Location:
    Western Washington
    Vehicle:
    2012 Prius
    Model:
    Three
    And considering that the passenger vehicle changeover from old carbureted engines to modern fuel injected engines was almost complete before 1990, it would seem that there should be a HUGE body of empirical evidence to reveal any widespread damage from 85 octane at high elevation. So far, for general consumer use, I'm hearing crickets.

    I won't deny that there may be lesser known corner cases where it is a problem, but it sure doesn't seem to be the norm.

    As for current Ford F-150s, note this highlighted portion of the 2021 F-150 Owner's Manual that was not called out in that video. While 87 octane is the acceptable minimum, Ford actually recommends 91 or higher octane. Therefore, this vehicle is not representative of the many cars for which 87 octane is recommended.

    upload_2021-10-3_19-1-46.png

    And concerning the video's worst case scenario, I just have to wonder: just where can one refuel an F-150 with 85 octane at 10,000 feet, and then without refueling, drive to sea level, hitch up a heavy trailer, and start climbing a long steep hill?
     
    #43 fuzzy1, Oct 3, 2021
    Last edited: Oct 3, 2021
  4. Gokhan

    Gokhan Senior Member

    Joined:
    Oct 5, 2008
    1,273
    603
    0
    Location:
    Paramount CA
    Vehicle:
    2021 Prius Prime
    Model:
    Limited
    Yup, it's an ancient story and probably mostly irrelevant today. That said, Mobil seems to claim that their premium gasoline may have more detergent. I use Chevron, and it seems to use the same amount of detergent for every octane.
     
  5. Gokhan

    Gokhan Senior Member

    Joined:
    Oct 5, 2008
    1,273
    603
    0
    Location:
    Paramount CA
    Vehicle:
    2021 Prius Prime
    Model:
    Limited
    Ford is not Toyota, and neither its octane nor its ethanol-level requirement is applicable to Toyota vehicles. Toyota vehicles do not benefit from high-octane gasoline, and they don't allow higher than E15 (15% ethanol) ethanol content.

    As for 85 octane in the mountains, I wouldn't mess with it and use the 87-octane mid-grade gasoline sold in those areas. If it were allowed, Toyota would mention it in the owner's manual. Today's electronically controlled engines don't care about the ambient oxygen levels as much, as they have built-in sensors to adjust for that.

    On that note, I used to run into leaded gasoline in areas of Wild West at gas stations that looked like from B-horror movies, and I am pretty sure neither Toyota nor Ford allows that.
     
  6. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    14,614
    10,269
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    Still, huh? I guess not as ancient and irrelevant as I thought.
     
  7. fuzzy1

    fuzzy1 Senior Member

    Joined:
    Feb 26, 2009
    15,315
    8,607
    90
    Location:
    Western Washington
    Vehicle:
    2012 Prius
    Model:
    Three
    That is not relevant to the high altitude 85 octane issue. Nevermind Toyota and Ford, the EPA never allowed leaded fuels in unleaded-era highway vehicles.

    Leaded gasoline is bad for catalytic converters (and for people), so the EPA required unleaded to be phased in ahead of the 1975 catalytic converter mandate. Unleaded cars have smaller fuel tank filler holes so that the old leaded nozzles shouldn't fit.

    Out here in the Wild West, many areas have climates that don't rust out vehicles very quickly, so there were many old leaded-fuel cars and pickups and other equipment still running for many decades after all new production was for unleaded fuel. (And numerous cheaters punched out their cats and ran cheaper leaded fuel regardless of the law.) The EPA finally shut down leaded fuel sales in 1996.

    For those of us who still use some some older agricultural equipment that needed leaded fuels for valve lubrication, there are other additives to do that job.

    I used 85 (and 85.5, maybe some 86 too?) octanes back on my old carbureted cars, where it was available, and have continued that practice with my modern fuel injected cars. No known problems yet.
     
    #47 fuzzy1, Oct 3, 2021
    Last edited: Oct 3, 2021
  8. Ovation

    Ovation Junior Member

    Joined:
    May 11, 2021
    90
    74
    0
    Location:
    Quebec
    Vehicle:
    2021 Prius Prime
    Model:
    Base
    In Quebec, the vast majority of premium (91 or higher octane) is ethanol-free, while the rest are typically E10 (I’ve seen some rare cases of E15 with 87 octane). But given that 91 is 15-20 cents more per litre than regular (which is averaging 1.45$/L at the moment), I can’t imagine the marginal fuel efficiency would compensate for the price difference. In my wife’s car (VW GTI), premium is strongly recommended. While not required, it does lose power on regular (not important for daily driving) AND increases fuel consumption (enough to wipe out the cost savings), so we bite the bullet.
     
  9. pghyndman

    pghyndman Active Member

    Joined:
    Dec 27, 2018
    365
    353
    0
    Location:
    CT shoreline
    Vehicle:
    2021 Prius Prime
    Model:
    Limited
    Therein lies the rub. The reduced efficiency negates savings and appears to primarily be a mechanism to funnel revenue (pork) to corporate corn farmers, the only beneficiaries of this bastardized fuel. Environmental benefits are certainly lacking as millions of gallons of diesel are needed to cultivate, reap, and process the ethanol, which itself reduces MPG in the recipient vehicles with no net benefit.
     
  10. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    14,614
    10,269
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    What does it do to the miles per gallon of gasoline?
     
  11. Colorado Boo

    Colorado Boo Member

    Joined:
    Jun 23, 2021
    276
    153
    8
    Location:
    Monument, Colorado USA
    Vehicle:
    2021 Prius
    Model:
    LE AWD-e
    Yep, that's smart...I also use the highest octane I can find for all my small engines. I believe the fuel stabilizer is good to use, especially if the gas is getting over 6-month old.
     
  12. Salamander_King

    Salamander_King Senior Member

    Joined:
    Nov 8, 2015
    8,757
    7,025
    0
    Location:
    New England
    Vehicle:
    2021 Prius Prime
    Model:
    Limited
    I don't know what the law is for the amount of gasoline a regular household can store in a garage, but I usually have a 2x 5 gal jerry can full of E0 gas with Stabil. I usually use up that amount within 6 months for various small engine tools and a generator, but if it is not finished by 6 mo. I just dump it in the car (not in PP) to refresh it. Right now, my PP is driven mostly on EV mode, it takes a couple of months to finish a tank, except when we take rare longer trips.
     
  13. Ovation

    Ovation Junior Member

    Joined:
    May 11, 2021
    90
    74
    0
    Location:
    Quebec
    Vehicle:
    2021 Prius Prime
    Model:
    Base
    It reduces them. Ethanol has less energy per volume than gasoline. The more ethanol, the lower the energy density.
     
  14. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    14,614
    10,269
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    By how much?

    And then, when you divide the miles driven by the quantity of gasoline in that ethanol/gasoline blend, how many miles were traveled per gallon of gasoline?
     
  15. Gokhan

    Gokhan Senior Member

    Joined:
    Oct 5, 2008
    1,273
    603
    0
    Location:
    Paramount CA
    Vehicle:
    2021 Prius Prime
    Model:
    Limited
    In those TGDI engines with very high BMEP values, I would use the highest octane gasoline I could find. Toyota engines have low BMEP values, and 87 octanes is fine.
     
  16. Ovation

    Ovation Junior Member

    Joined:
    May 11, 2021
    90
    74
    0
    Location:
    Quebec
    Vehicle:
    2021 Prius Prime
    Model:
    Base
    I’m not certain I understand the need for this degree of granularity. It’s enough (for me) to know that ethanol has a lower energy density than gasoline and choose accordingly (depending on the vehicle) according to cost, availability, etc. of the fuel blend.
     
  17. Gokhan

    Gokhan Senior Member

    Joined:
    Oct 5, 2008
    1,273
    603
    0
    Location:
    Paramount CA
    Vehicle:
    2021 Prius Prime
    Model:
    Limited
    Ethanol in fuel | fueleconomy.gov
     
  18. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    14,614
    10,269
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    The link Gokhan supplied doesn't answer the question, but it does give the information from which the answer can be worked out. It says

    "Ethanol contains about one-third less energy than gasoline. So, vehicles will typically go 3% to 4% fewer miles per gallon on E10 ...".

    At the same time, in 10 gallons of E10 there are only 9 gallons of gasoline.

    So suppose you get 52 MPG on straight E0 gasoline. That might drop to 50 MPG on E10—but you drove those 50 miles on only 0.9 gallons of gasoline. That's 56 miles driven for every gallon of gasoline you burned.

    This matters if one of the goals is to burn less fossil fuel for the same miles driven. Every 728 miles you drive would be 14 gallons of E0 gasoline at 52 MPG, but only 13 gallons of gasoline in the 14½ gallons of E10 you could have burned in the same distance. You'd be using a gallon less gasoline every 728 miles. For most people, whose cars have lower MPG, it doesn't even take that many miles.

    The point about some amount of diesel being used to farm and process the corn is a fair one, and somebody needs to think about whether that is so much that it outweighs all the gallons of gasoline being saved (as if nobody has already).

    The 337 million gallons of motor gasoline, mostly E10, sold every day in the US is more than the 324 million that would be needed to cover the same miles if it were E0. But the 337 million E10 gallons are only 303 gallons of gasoline. That's 21 million gallons of gasoline saved. Per day.

    Don't know how many corn harvesters that comes out to.
     
    #58 ChapmanF, Oct 8, 2021
    Last edited: Oct 8, 2021
  19. Gokhan

    Gokhan Senior Member

    Joined:
    Oct 5, 2008
    1,273
    603
    0
    Location:
    Paramount CA
    Vehicle:
    2021 Prius Prime
    Model:
    Limited
    Ethanol is claimed to be somewhat carbon-neutral, but the main reason E10 traditionally has been used is to oxygenate the gasoline to reduce the carbon monoxide and hydrocarbon emissions.

    Ethanol and the environment - U.S. Energy Information Administration (EIA)

    Gasoline Winter Oxygenates | US EPA

    https://www.eesi.org/articles/view/ethanol-reduces-a-variety-of-harmful-emissions-new-study-finds

    And then there is MMT for oxygenation, which is hopefully not in your gasoline but you are in tough luck if you are in Canada.

    EPA Comments on the Gasoline Additive MMT | US EPA
     
  20. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    14,614
    10,269
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    Still, even if burning 21 million gallons less gasoline a day is just the bonus decoder ring in the box, I'll take it! :)
     
Loading...