Premium fuel...................worth it ?

Discussion in 'Bad Dog Cafe' started by Tomm Williams, Feb 13, 2019.

  1. Tomm Williams

    Tomm Williams Tele-Holic

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    Late last year I purchased a 2018 F150 with the 2.7L V6. My initial mileage (according to the computer) reached a max of 23.7 and then slowly started going down and leveling off at 21.2 or so. As an experiment, I've now run about 25 gallons of premium through it and the mileage has climbed back to 21.9.
    According to most every info site I can find, premium isn't known to be of any benefit increasing MPG yet there it is. I have a 500 mile round trip planned next week as my final test to see how close I can get back to the 23.7 I started with.
    Now I have not bothered with the math to determine at what point fuel at .30 cents /gal more is a benefit but have to wonder if it's just a better choice for the engine overall? I don't tow anything, it's just a 4WD passenger vehicle 99% of the time. There must be some reason the engine is responding positively to premium?
     
  2. Danjabellza

    Danjabellza Friend of Leo's

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    I could be you subconsciously driving more economically due to the increased cost of the fuel... maybe?
     
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  3. chris m.

    chris m. Poster Extraordinaire

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    Premium only matters for really high compression engines that require it. This is typically for high performance engines such as BMW and Porsche.
    The higher octane prevents premature combustion (knocking). If your engine doesn't require it, it is a total waste of $$.

    There are a few things more likely going on.
    1) Gasoline often has alcohol mixed in for a variety of reasons. Alcohol has less energy density than gasoline, so the higher the alcohol content,
    the lower your resulting mileage will be. The percentage of alcohol can vary with the brand, but also with the specific formulation, which typically
    gets adjusted seasonally to help manage smog.
    2) Gasoline formulations, change, often seasonally, and not just alcohol content. For example, in California the refiners change the formulation at different times of year
    to reduce pollution depending on the season.
    3) Gasoline density is different depending on whether it's hot or cold. It is denser when it is colder. So you will get slightly more miles per gallon when
    the gasoline is colder than when it is warmer.
    4) Your mileage will vary a lot with the weather. Not only because the gasoline density and formulation is likely different, but because your vehicle
    is dealing with different weather. For example, the engine takes longer to warm up in cold weather and gas mileage isn't optimal until the engine
    hits its ideal temperature range.
    5) A heavy vehicle like an F150 has a pretty big delta between steady, highway driving vs. start and stop. It takes a lot of energy to get that mass
    rolling from a stop. Very small changes to your mix of highway vs. city driving can have a pretty big impact on your net gas mileage.
    6) I hope your State's Bureau of Weights and Measures regularly inspects your retail gas station pumps. They can make a whole lot of money over time if they
    actually give you just a little bit less gasoline than the pump readout says.
     
  4. chris m.

    chris m. Poster Extraordinaire

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    And the huge one: check your tire pressure!! If your tire pressure is low you will get lower gas mileage. Tire pressure tends to go down
    over time if you don't stay on top of it.
     
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  5. stephent2

    stephent2 Poster Extraordinaire

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    Strange, I grew up thinking common knowledge was you get slightly better mileage w/ high test. I'm sure it varies w/ the car. On some cars the computer adjusts to your driving habits, don't know if that includes type of gas.

    And cars spec out for regular or premium. My Subaru takes regular and didn't seem to run as good w/ the one tank of premium i've used. I think long term, using top tier gas is more important than a premium grade unless your auto requires it.
     
  6. Ignatius

    Ignatius Tele-Afflicted

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    I experience just the opposite. And I don't warm up my engine in the winter. Hmm...
     
  7. getbent

    getbent Telefied Ad Free Member

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    I think if you run a couple tanks of chevron gas or buy a couple bottles of techron and run it with regular gas, you'll achieve the same result. What I believe (faith based so, not fact based) is that ford products run optimally around 2K rpm. If you can run at about 1850-1900 you'll get max mpg. After many years of driving priuses and learning the trick to 'get to 50' you learn the sweet spot of the car and then it becomes sport. That same prius only nets my daughter 43 mpg... driving technique.

    With my 5.4 F150 I get 17.1 with that rpm formula AND running every 8th tank with techron... I drive about 90 miles a day for work... so, I have time to futz with this... my other gas is sometimes at a name station and most at a 'moe's' or some no name place. I have run premium, but it is mostly lost on an engine like the 4.6 or the 5.4. My wife's edge has the 4.6 and our experience is similar, but she is a bit of a leadfoot/hard braker so, she does not maximize her mpg. The techron in the gas aids in cleaning the injectors... which makes the engine more efficient.

    In re reading your post... you have to consider that the prediction model it uses is fluctuating along the way... new tires etc, time of year, all those factor into it. You can make sure your tires are inflated to the correct psi and probably impact your mileage more than gas type.
     
    Last edited: Feb 13, 2019
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  8. getbent

    getbent Telefied Ad Free Member

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    Your tires are probably under inflated in the winter and so, worse mileage.
     
  9. Buckocaster51

    Buckocaster51 Super Moderator Staff Member Ad Free Member

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    I’ve told this story before:

    I was once a leader of a group of Explorer Scouts that went dinosaur bone digging way out in the northwest.

    We rented two identical Ford minivans. One blue and one red. I started driving Blue and for the first day got right around 21 mpg. Red got something like 18 mpg. This was in 1990 and those were pretty typical numbers. I bragged up my driving skills and red driver said it was the van, not the driver.

    So the next day I drive red and he drove blue. Once again I was at 21 and he was at 18.

    This went on for two weeks...maybe more because I thought I slept on the ground for 30 straight days.

    Watch how hard you step on the gas

    Unless you hAve regenerative braking, breaks are the enemy of good fuel mileage

    Avoid ethanol blends if you can. The BTUs in the ethanol are less than the BTUs in the gasoline it displaces. (If you can, keep track of your cost/mile)

    As long as your engine is not predetonating, there is no value in buyer higher octane fuel

    Keep air in those tires!
     
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  10. TheGoodTexan

    TheGoodTexan Moderator Staff Member Ad Free Member

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    I use regular grade ethanol-free fuel in my ‘17 Tacoma, with 4 ounces of Lucas Oil fuel additive per tank, with the ECT “always on”... and get a verified 3 mpg more than standard gas.

    That’s 23 mpg, as compared to 20 with standard fuel and no additive, and the ECT off.
     
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  11. CK Dexter Haven

    CK Dexter Haven Friend of Leo's

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    I used it in cars that specified it, I use regular in those that specify that. As mentioned you will see a noticeable increase in gas mileage by adjusting your driving habits, + your drive train components may also last longer if not constantly subjected to rapid acc/dec. I drove older cars for many years and found that 60mph on the highway, gets you there in plenty of time, seems to return reasonable gas mileage, and reduces wear and tear..most auto engineers will tell you that crusing at +/-60 is about the least stressful thing you can do to a vehicle. I live in a area where we have many folks who do long commutes at 70+ in large vehicles that are basically elevated boxes, w/ huge engines to move that mass, can't imagine what the fuel bill is like. The odd thing is the blow past me, and 15-20 miles later I catch up with them where the road narrows or the limit drops to skirt a town. I can get almost 40mph at 60. City driving is much the same, what are you gaining by blasting away from a light or passing slow traffic on the shoulder /double yellow so you can sit longer at the next one? If you have a normal urban route you can soon get the hang of the light timing/bottlenecks and move smoothly thru traffic.
    This type of driving will save you much more than any modest increase that unwarranted use of premium fuel might return.
     
  12. telemnemonics

    telemnemonics Doctor of Teleocity Ad Free Member

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    Virtually every modern car engine with a computer and no distributor, adjusts for the fuel octane, the engine temp, the air temp, and the load, at the very least advancing and retarding the timing, if turbo adjusting the boost pressure, and in some cases adjusting the air fuel mixture.

    Premium will allow the computer to raise the bar a little by advancing the timing and whatever else your engine does.

    Some higher performance cars suggest premium in summer when air temp requires the computer to further retard timing (and lower boost) to avoid detonation.

    A test to make you more comfortable is pulling a too tall gear up a long hill and listening for knock. I've had computer controlled engines that would still knock pulling hard at lower rpm. If it never knocks you're fine with regular, and any increased performance the computer dials in for premium might not be worth the price per gallon.
     
    Last edited: Feb 13, 2019
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  13. zipseattle

    zipseattle Tele-Meister

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    Years ago, i had an older car that probably had a lot of carbon build up and knocked a lot in the summer unless I added a little premium to the tank. Was too broke to fill it up with premium, so I'd only mix in enough to reduce the knocking.
     
  14. telleutelleme

    telleutelleme Doctor of Teleocity Silver Supporter

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    If my wife drives we get better MPG but it takes twice as long to get anywhere. I guess there is a trade off.
     
  15. PastorJay

    PastorJay Tele-Afflicted

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    Years ago, I bought a car that didn't run well. I took it back to the dealer and the service dept couldn't find anything wrong with the car. They asked me what kind of gas I bought. When I told them, they said to stop buying that and instead buy only Chevron or 76. Mobil or Shell in an emergency. Not to buy anything else.

    I started following their advice and the car started running better on the second tank.

    Years later I still stop at only those four companies.

    YMMV. Literally.
     
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  16. SacDAve

    SacDAve Poster Extraordinaire

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    I've always thought you should buy the grade your vehicle is designed for otherwise you can damage the engine? My car takes supreme what I found out from personal experience if I go to the cheaper gas stations, I notice deference in how my car runs. Also, all grades of gas are the same all the brands are mixed together before they are pumped to the distribution locations through the pipe lines. The additive for each brand of gas are added at the distribution locations before delivered to gas specific stations.
     
  17. SacDAve

    SacDAve Poster Extraordinaire

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    that's exactly was I was told buy the service department.
     
  18. CK Dexter Haven

    CK Dexter Haven Friend of Leo's

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    Use to "decoke" w/ a can of GM Top Engine Cleaner, take care of that and every mosquito in a 10 mile radius, you only made the mistake of doing it in the bay one time...
     
  19. blowtorch

    blowtorch Telefied Ad Free Member

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    Premium gas = a tax on those who believe that more expensive always means better :)
     
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  20. CK Dexter Haven

    CK Dexter Haven Friend of Leo's

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    When Techron (Chevron) came out it was some what unique, it's introduction coincided w/ fuel injection becoming common, it kept injectors cleaner than other fuels at the time, BMW recommended adding it in bottle form in areas where Chevron was not available. Most fuels now have a comparable additive package. I have used Shell and Sunoco for years in multiple vehicles w/ no problem.
     
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