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Top Tier Gas – Medicine for Your Engine

When you fill up your car with gas, what’s the main deciding factor between one brand and another? If you’re like most people, it’s price. Perhaps you’re even willing to drive out of your way to save a few pennies on the gallon. But could this cheaper fuel be poisoning your car, potentially leading to costly repairs and even damaging its resale value? Many automotive experts recommend using top tier gas to enhance a car’s performance and potentially reduce the risk of engine damage. Why?

What is top tier gas?

Top tier gasoline may help reduce the build-up of ‘gunk’ in the engine which comes from impurities in gas. These are broken down by adding high levels of detergents to the fuel. Top tier is also free of metallic additives, improving its quality. It is usually slightly more expensive than regular fuel, but only by a few cents per gallon. It was developed to protect the engines of cars with fuel injection technology. During the 80s and early 90s car manufacturers were reporting that the engines of cars with direct fuel injection were getting clogged with gunky build-ups, originating from impurities in gasoline. As a result, the Environmental Protection Agency (EPA) started regulating minimum levels of detergent that need to be present in gas to break down impurities, with the idea of improving fuel quality. Unfortunately, some suppliers reduced the amount of detergent in their gasoline to the specified minimum, reducing the overall quality of fuel available instead of increasing it. In the early nineties some of the world’s biggest auto manufacturers including Audi, BMW, General Motors, Mercedes Benz, Volkswagen, Honda and Toyota set higher benchmarks for top tier fuel. In order to brand their fuel as top tier gas, retailers must ensure that is has two to three times more detergent than the EPA minimum, which combats gunk build-up, and is free of metallic impurities which damage vehicle’s emission-control systems.

Is it different to premium fuel?

Yes. Top tier fuel is different from high performance premium fuel, which has higher octane levels. Top tier octane levels are the same as regular fuel.

Why would I use top tier fuel?

What regular gas does inside your engine.
What regular gas does inside your engine.
How top tier gas helps your engine
How top tier gas helps your engine.

There is some controversy within the auto industry about whether top tier gas is worth the extra money, with some critics labelling it as a marketing ploy to make more money for fuel suppliers. However, numerous automotive experts suggest using top tier fuel, even if not for every tank. The main reasons they recommend it is to help avoid:

  • Increased deposits on fuel injectors and intake valves
  • Consequent misfiring spark plugs and reduced performance
  • Reduced emission efficiency
  • Repair bills of up to $1000 for a cylinder-head rebuild

If you have a fuel injection vehicle that needs repairs as a result of excess deposits, this could affect the resale value of your car. Some people prefer to use fuel-system cleaning products as they can be cheaper than buying top tier gas regularly, but high levels of these products have the potential to damage catalytic converters. You don’t need to use top tier gas in every tank to get the benefits either, as its unique formulation means that one tank can remove the residue from several tanks of regular fuel. The detergents bind to injectors and valves, protecting against further build-up too.

Where can I find top tier fuel?

You might already be using it without realizing, as 40% of all the gas sold in the United States is top tier. Top tier is sold at gas stations across the country, including major companies like BP, Chevron, Texaco, Costco and Exxon. You can check the top tier site for details of all retailers. Use our free CARFAX records check to see how many service records a used car has – this could highlight problems created by gunk build up among many others. Or see the service records for free on any CARFAX listed used cars. What do you think? Do you use top tier fuel or not, and why?

17 thoughts on “Top Tier Gas – Medicine for Your Engine”

  1. Great post guys, I have always been wondering whether 93 octane gas has made MUCH of a difference. Now I know.

    Also, I must recommend using fuel injector cleaners regardless of octane level.

  2. The high octane fuels are overall, much better for your vehicle. The other good option is octane boosters which sometimes can raise the octane level over 100. (Great for burning off some carbon).

    Thanks for the “very” detailed article.


    1. Octane is added to eliminate engine knocks. That’s it. If your engine doesn’t knock with 87 octane, then anything higher is a waste of money. Only high performance engines with high compression ratios need higher octane.

      1. False. GM vehicles have two octane tables. One for LOW octane and the other for HIGH octane fuel. When you put premium into the tank, the computer will run the high octane table giving you greater performance and usually better fuel economy.

        1. Studies show using premium in an engine that does not require it is a waste of money. Even in GM cars the increase in mpg using premium comes nowhere close to the additional 30 to 40 cents per gallon. Consumer Reports saw less than a 1 mpg increase using premium fuel.

  3. The article states: During the 80s and early 90s car manufacturers were reporting that the engines of cars with direct fuel injection were getting clogged with gunky build-ups . . .

    This is untrue. We did not have direct fuel injection engines until about 2008 or possibly a bit earlier. Fuel injection started to come on during the late 80’s but that was port fuel injection which is largely different from direct injection and the problem was not that then engine was “clogged with gunky build-ups”. More specifically, the injectors were getting clogged. This is not much of a problem any more but direct injection engines are having severe problems with carbonizing in the intake ports because no fuel passes through them allowing the fuel detergents to keep the port clean.

    This is a problem that Top Tier fuels can only partially address.

    1. Houckster,

      Whilst I appreciate your candour, Gasoline Direct Injection certainly pre-dates 2008 as well as WWI. I would venture to say you are one of those that believe the electric car was founded with the first Prius. Knowledge is power mate!

      Superbly written article!

      Much Thanks.

      1. Obviously, all diesel engines are direct injection. So it has been around for a long time. However, when was direct injection first used in non-diesel, automobile gasoline engines? It’s only been a big marketing point with the auto manufacturers for the past few years. Please give me a source for you comments.

    2. Direct fuel injection has been around since at least the 1920’s. It became more popular and cost effective in the 2000’s as the price of oil increased but it is NOT new.

  4. Fuel additives, and fuel for that matter, don’t touch the valve stems in GDI cars, as the gasoline is injected directly into the combustion chamber. So while a top tier fuel can help keep the injectors themselves clean, it does nothing for the valves. And the valves will gunk up due to the PVC valve that recycles blowby gases back into the intake manifold. Vaporized oil will collect on the valves and the valves will not be cleaned by any additive or fuel detergents. In this case you either have to dismantle the head and manually clean the valves (walnut shell blasting) or pay to have something like a BG fuel cleaning system used. In the case of my 2012 Genesis, I opted to install an oil “catch can” to collect and condense oil vapors before they deposit on the valve stems and backsides.

  5. Retired automotive engineer here….
    Going from my bad memory, BMW was the first manufacturer to diagnose and offer a fuel recommendations to cure a new form of engine deposits showing up in cars during the 80s. I believe top tier did not exist as an organization at the time. Some may recall the Texaco TV ads back then (80s) saying, just give us a try for 5 tanks and you’ll feel the difference. Texaco was meeting the recommendations BMW had written. Today we have a nice published list thanks to top tier and it’s no longer the secret it was in the 80s.

    Let’s not confuse the issue with talk of octane. This has nothing to do with it.

  6. I just bought a car that calls for premium fuel. So is the top tier discussion irrelevant to me? If not now what?

    1. Top tier has nothing to do with octane, they are totally different subjects. Either hi or low octane can be a top tier gas.

  7. So AAA says one thing in an article while the head of AAA says this

    Oil companies spend lots of money explaining why their gas is better than the competition’s. Chevron’s gas, for example, is fortified with “Techron,” and Amoco Ultimate is supposed to save the planet along with your engine. But today more than ever, one gallon of gas is as good as the next.

    True, additives help to clean your engine, but what the companies don’t tell you is that all gas has them. Since 1994 the government has required that detergents be added to all gasoline to help prevent fuel injectors from clogging. State and local regulators keep a close watch to make sure those standards are met; a 2005 study indicated that Florida inspectors checked 45,000 samples to ensure the state’s gas supply was up to snuff, and 99 percent of the time it was. “There’s little difference between brand-name gas and any other,” says AAA spokesperson Geoff Sundstrom.

    What’s more, your local Chevron station may sell gas refined by Shell or Exxon Mobil. Suppliers share pipelines, so they all use the same fuel. And the difference between the most expensive brand-name gas and the lowliest gallon of no-brand fuel? Often just a quart of detergent added to an 8,000-gallon tanker truck.

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