Car Talk and premium gas

Discussion in 'General Motoring' started by -rick-, Apr 12, 2007.

  1. -rick-

    -rick- Guest

    Did any one happen to catch Car Talk last Saturday where
    they advised (I'm paraphrasing) that it was a waste of money
    to use premium gas. I expected some qualifications to
    follow but they left it as a broad truism that the knock
    sensor would prevent damage and made no mention of reduced
    efficiency or performance.

    Does any one know of any valid data to support or refute
    their claim?
     
    -rick-, Apr 12, 2007
    #1
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  2. -rick-

    houndman Guest

    I heard it and was puzzled, but then I don't know the new electronics
    and the like. Would like to hear what people have to say.

    Maybe asking on their web site would bring clarification.
     
    houndman, Apr 12, 2007
    #2
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  3. -rick-

    B A R R Y Guest

    Read your owner's manual for what you should use in your vehicle.

    Cars that require or "recommend" premium often run more efficiently or
    more powerfully on premium. Cars that recommend regular (most cars)
    usually get zero benefit from higher octane, so premium is simply a
    waste of money. Here in the most highly marketed-to-in-the-world North
    American society, we tend to buy into the "upscale" mentality of more
    expensive = better.

    I have MPG data from every tank of gas for my 2005 Tacoma in Quicken.
    Toyota recommends premium for the 4L V6. If I spend the ~$0.30/gal
    extra for premium, I get enough extra miles to actually make it
    slightly cheaper per mile than regular, and get better performance under
    stress (towing and hot / higher atmosphere) as a freebie!

    My '99 Wrangler and 2001 H4 Subaru got exactly the same mileage and no
    noticeable performance gain on 87 vs. 91+, so premium was a complete
    waste of money.

    Cars that _require_ higher octane in the manual can be damaged by lower
    octanes, and should not be run on regular.
     
    B A R R Y, Apr 12, 2007
    #3
  4. -rick-

    bigjim Guest

    Premium is a waste of money. Yes performance may suffer but not for a
    daily driver. No damage will result. What if premium isnt available.
    Do you really think your car will explode if you use regular? I have
    personal experience with a 2001.5 Passat that "required" premium
    fuel. Never used it and car ;lasted 140k + before tradein. None of
    the numerous mechanical problems car suffered could be attributed to
    gas . You are free to give oil companies more but I wont
     
    bigjim, Apr 12, 2007
    #4
  5. -rick-

    KLS Guest

    Thank you for this excellent post. You said it far better than I
    could, especially with your empirical evidence to back it. I don't
    know why people buy cars that require premium gas and then don't feed
    the cars properly. Why did they buy those cars, then?
     
    KLS, Apr 12, 2007
    #5
  6. -rick-

    bigjim Guest

    I buy a car for the car- style, design, capabilities, utility etc.
    Gas is gas so I dont consider it.
     
    bigjim, Apr 12, 2007
    #6
  7. Hi,

    Barry already said everything that was going thru my head. My old Subie
    says "regular" and only during the very hottest months of summer have I
    been able to see any difference when I've tried "higher" grades (cuz it
    pinged like crazy.)

    OTOH, a slightly newer 3.0l V-6 Camry sitting on the driveway will run
    on anything, but DOES do better, as the book says it will, by going to a
    higher grade just as Barry's Taco does. I assume it's got a lot to do
    with improving fuel and engine management systems as the years go by?

    Rick
     
    Rick Courtright, Apr 12, 2007
    #7
  8. -rick-

    B A R R Y Guest

    A sample of one, in sea level NJ. <G>
     
    B A R R Y, Apr 12, 2007
    #8
  9. -rick-

    Fuzzy Logic Guest

    It's generally considered a waste IF the manufacturer recommends regular fuel. If the owner's manual states
    premium fuel you should be using it. Here is an article on this topic:

    http://www.canadiandriver.com/articles/jk/040728.htm
     
    Fuzzy Logic, Apr 12, 2007
    #9
  10. -rick-

    JD Guest

    I can tell you that an STi can produce audible pinging on 91 on a hot day
    from experience; because the base timing is reached and it can't be retarded
    further. Just about every automotive source indicates that audible pinging
    in a modern engine with a knock sensor usually means damage is occurring.
    Given that, I only use 93 or better in the STi, and drive sedately on 91 in
    the summer. So, you can bet regular would definitely damage the engine if
    driven hard.
     
    JD, Apr 13, 2007
    #10
  11. -rick-

    bigjim Guest

    Yu are free to keep inflateing oil company profits. Pinging is
    normal and indicates maximum efficiency
     
    bigjim, Apr 13, 2007
    #11
  12. Pinging is fuel detonating, not burning smoothly and not normal.
    That is bad.
    If pinging is present in an engine, excessive amounts of heat and stress are
    generated and will cause destruction of engine components such as pistons
    and valves.
    I'd check that out if I were you....try Google....don't take my word for it.
    As a rule (in the UK) the higher octane fuels we have (95 to 102) also have
    detergents and other additives to keep the fuel system clean which is an
    additional benefit.
    My WRX most certainly runs better on 99 (+5% bioethanol) than 95 so better
    all round, a little greener and who cares about a few pennies extra per
    litre for a top quality product?
    -C-
     
    Clive - Selectron, Apr 13, 2007
    #12
  13. Hi,

    Methinks you've got it a bit off: maximum efficiency comes JUST BEFORE
    pinging according to all sources I've ever researched. Pinging is
    uncontrolled, therefore it's hard to believe it's efficient!

    Rick C
     
    Rick Courtright, Apr 13, 2007
    #13
  14. -rick-

    Fuzzy Logic Guest

    wrote in
    Not unlessyou are using a Bourke engine <http://en.wikipedia.org/wiki/Bourke_engine>

    Pinging aka detonation is not good for conventional internal combustion engines:

    It is caused by an instantaneous ignition of the remaining fuel/air mixture in the form of an explosion. The
    cylinder pressure rises dramatically beyond its design limits and if allowed to persist detonation will damage
    or destroy engine parts.
     
    Fuzzy Logic, Apr 13, 2007
    #14
  15. -rick-

    JD Guest

    Pinging is NOT normal and it is not good for the engine. If you think
    otherwise, go read some more.
     
    JD, Apr 14, 2007
    #15
  16. -rick-

    Phil Guest

    Pinging is normal and indicates maximum efficiency

    What the fk ???
     
    Phil, Apr 14, 2007
    #16
  17. -rick-

    bigjim Guest

    A vehicle is at maximum efficiency at the stage right before pinging
     
    bigjim, Apr 14, 2007
    #17
  18. -rick-

    JD Guest

    And is in a danger zone once pinging starts. Pinging is NOT normal and
    extremely distructive.
     
    JD, Apr 14, 2007
    #18
  19. -rick-

    Phil Guest

    Pinging is normal and indicates maximum efficiency
    It may well be, but that's not what you said.
     
    Phil, Apr 14, 2007
    #19
  20. -rick-

    bigjim Guest

    My 94 Trooper manual said something like "occasional light pinging
    upon accelleration indicates vehicle is at optimum efficiency" .
    Truck occasionally pinged and lasted 140+k miles before it was hit and
    totalled. Engine appeared to have much life in it so I cant accept
    there was any "damage".
     
    bigjim, Apr 14, 2007
    #20
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