Ok so when you go to the gas station there are three "grades" of gas (there's also diesel but that's not relevant here):

  1. Regular - this is what pretty much most people get.
  2. Plus - Why????
  3. Premium - for luxury/sports cars

So can someone explain what the hell the "plus" is for?

  • Elon_Musk [none/use name]
    ·
    edit-2
    4 years ago

    Higher octane gas burns slower preventing pre detonation and knocking in higher compression engines. Higher compression engines make more power and higher efficiency. https://www.youtube.com/watch?v=4ZysyokEU60

    "Midgrade fuel doesn’t really exist. In most cases, refineries do not produce a midgrade gasoline blend; instead, the middle-octane option is blended at the fuel pump from a given gas station’s supply of regular and premium gas. Midgrade fuel began appearing in 1995, as leaded gasoline was being phased out. At the time, most gas retailers were selling regular (leaded), unleaded (what we now call regular), and premium unleaded gasoline. When leaded gas was phased out, most retailers were left with the infrastructure to dispense three types of fuel, but only two types to sell. Thus was midgrade fuel born."

  • CarlTheRedditor [he/him]
    ·
    4 years ago

    The Volkswagen GTI VR6 that I drove had a minimum octane rating requirement that was met by mid-grade gasoline.

    • Shinji_Ikari [he/him]
      ·
      4 years ago

      A lot of older turbo cars had the same thing, basically minimum to keep the engine working right and in a range the computer can adjust to.

    • FloridaBoi [he/him]
      ·
      edit-2
      4 years ago

      Leaded gasoline was banned in the 70s

      Edit: holy shit it wasn’t actually banned until the 90s

    • red_stapler [he/him]
      ·
      edit-2
      4 years ago

      It’s going to be fascinating to see what the world is like when the most lead poisoned generations die off. I wonder how much of the generational chasm we see between boomers and the younger generations is lead poisoning.

  • fed [none/use name]
    ·
    4 years ago

    I have to buy premium for my motorcycle engine and plus for my moped

  • LangdonAlger [any]
    ·
    edit-2
    4 years ago

    Some cars that operate at a higher compression in the engine needs a higher octane gas; turbo and supercharged cars, mostly

    • BoxedFenders [any, comrade/them]
      ·
      4 years ago

      Yep, and now that most cheap economy cars are turbocharged now they require higher octane fuel to meet their published MPG rating. So it isn't just about cheaper gas for cheaper cars. The manufacturers account for this, and build them so they run on lower octane fuel anyway knowing how careless the average carowner is. But it isn't optimal, and you may even be losing more money this way through loss of efficiency. But using "premium" on a car rated for 87 octane is a complete waste of money as nothing is gained by it. Back in the pre-internet days, people would spread some weird urban myths about gas, like thinking premium fuel would clean your engine or some other such nonsense.

    • FloridaBoi [he/him]
      ·
      4 years ago

      OP is asking about mid grade and I think most new cars don’t specify it, only regular or premium. I think some imports from the early 2000s may have required 89 but I have never seen it irl

      • furryanarchy [comrade/them,they/them]
        ·
        4 years ago

        Even if they don't specify it, they often want it anyways. Most NA BMWs call for premium but will run midgrade, almost every Volvo calls for midgrade, Mazdas get a noticable improvement in performance from midgrade but only call for regular, etc.

  • ElGosso [he/him]
    ·
    4 years ago

    So someone else pointed out that it's about octane - some engines are built around using higher octane gasoline, and some lower. Should say in your owners' manual which kind to use.

  • DirtbagVegan [he/him]
    ·
    4 years ago

    It's what I put in my lawnmower. It recommends 90 octane, but usually the mid-grade is 89, which seems to be close enough to work well.