Regular unleaded vs. super unleaded?

Discussion in 'Planes, Trains & Automobiles' started by justyn93, Jun 15, 2011.

  1. #1 justyn93, Jun 15, 2011
    They both cost the same, so what should i use for the best mpg? I have poor gas millage in my 96 lexus es300, i got new spark plugs, fuel filter, oil, tires are full, and i took my spare tire out. I have a hole in my exhaust somewhere, could that be causing my issue?


    Sorry for getting off topic. lol
     
  2. #2 Footbag, Jun 15, 2011
    They shouldn't cost the same. The higher the octane (super) should cost more. If they are mysteriously the same price in the gas station near you, go with the super.

    Although higher octane is usually more expensive, it takes less for combustion.. thus evening out in price.

    The hole in your exhaust is probably causing you gas mileage issues. Is your check engine light on because of it? Anyways, a problem with your exhaust is most likely causing your car to run 'rich'. Do you ever see liquid dripping from your tailpipe? That's gas. Good luck.
     
  3. #3 justyn93, Jun 15, 2011


    Its only like this at a few gas stations where i live... The check engine light never comes on, but my car does idle pretty low ~500-800rpm
     
  4. #4 Cannibetrue, Jun 15, 2011
    You do understand that higher octane is combusted at a higher temperature right? That means it takes MORE heat to cause it to combust. Here's an article on the matter:

    Mythbusting Octane, The Truth About Gasoline

     
  5. #5 schultzy225, Jun 15, 2011
    As said above, run whatever your car calls for. There isn't an advantage to running a higher octane. But if it calls for premium make sure you use premium, I see too many people put regular in cars that calls for premium :rolleyes:
     
  6. #6 justyn93, Jun 15, 2011
    Does anyone know if exhaust tape works? I've heard mixed reactions on this.
     
  7. #7 Spacepope, Jun 15, 2011
    If you have a hole in your exhaust, get it fixed. Don't half ass it. Half-ass repairs are almost always the cause of super expensive repairs.
     
  8. #8 lizardslap, Jun 15, 2011
    Last edited by a moderator: Jun 15, 2011
    use an old beer can and clamps thats what I did but if your car runs really hot it wont hold just like the tape
     
  9. #9 Feel Good Inc, Jun 15, 2011
    Last edited by a moderator: Jun 15, 2011
    Super/Premium fuels are usually called in for higher performing cars...i.e high compression naturally aspirated, boost-turbo or supercharged. In both cases the air and fuel mixture is further compressed or under increased pressure and heat. Premium fuels are not supseptable to detonation. Detonation kills motors. Info might not be 100% correct but this is just off the top of my head. Btw I am a car nut.
    Also more and more cars are calling for premium fuel these days. Under pressure to keep engine size down and power up more and more mid-entry level cars are coming equipped with turbos and superchargers.
    Using premium fuel in a motor thats made to run on regular will give you ZERO benifit.
    Unless you modify the motor but thats another book.
    Ok thats all I got
     

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