Prius

Make
Toyota
Segment
Hatchback

The automotive industry is full of hyperbole, especially when it comes to gasoline. Each gas station claims to have the best gas for your car, encouraging you to buy its priciest product with fake scientists in real commercials (that'd be you, Shell). Take "Top Tier" gas, for instance. The name alone sounds awesome and the fact that it's backed by eight massive automakers seems to make it worth the premium. But is it really better for your car? AAA decided to find that out by conducting a study.

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Before we get into the methodology of this study and its findings, here's a quick crash course on Top Tier gas. Essentially, this magic fuel just has more detergent additives, with the idea being that the higher-quality fuel is better suited for today's increasingly complex engines. It comes in a variety of octane ratings and is backed by the following automakers: BMW, General Motors, Fiat Chrysler Automobiles, Honda, Toyota, Volkswagen, Mercedes-Benz and Audi. For its study AAA enlisted the help of an independent testing facility. The test consisted of running an engine continuously for 100 hours straight, with the process simulating 4,000 real-world miles.

Six different fuels were randomly selected, three that were Top Tier and three regular petrol products. After the test concluded the engine was disassembled and its parts photographed. What were the results? Carbon deposits on injectors, intake valves and inside the combustion chamber were 19 times higher on engines run using basic gas than on those powered by Top Tier. In addition to leaving behind less carbon Top Tier gas also helped clean out engines, with intake valve deposits dropping by 45% to 72% over a 5,000 mile interval. (The variation is due to the fact that different brands of Top Tier gas, which is just a designation, were used.)

Consumer Reports checked out gas prices over a year and found that Top Tier fuel cost an average of just three cents more than non-Top Tier gas. There's a lot that goes into keeping a car running, and higher-quality gasoline isn't the biggest factor by a long shot. That being said it does make a difference and is something drivers shouldn't overlook, especially when studies like this one prove that the benefits easily outweigh the costs.