For many drivers, when the fuel gauge nears empty they pull into the whatever gas station is most convenient, or has the lowest price. However, there are subtle differences between various brands and the specific formulations they mix into the fuel.
All gasoline sold in the U.S. meets minimum requirements set by the government. The differences between brands come in the additives and detergents added to the blend to help extend the life of the engine.
Some fuel companies — working with major automakers that include BMW, Fiat-Chrysler, General Motors, Honda, Mercedes-Benz, Toyota, Volkswagen/Audi — have taken it a step further, setting a higher standard that has become known as Top Tier fuels. Brands that qualify as Top Tier contain additional detergents beyond the minimum requirements, and help prevent carbon buildup in car engines.
Over time, the furnace that is the modern engine will accumulate carbon residue, a byproduct of the motor's combustion process that happens thousands of times per minute. Like barnacles on a boat, carbon deposits can build up on vital engine parts, like valves, pistons and the combustion chamber. As the carbon accrues, engines will run rougher and less efficiently (ie, less power or decreased fuel economy).
According to one AAA survey, Top Tier fuels left 19 times fewer deposits after simulating driving 4,000 miles in an engine lab. Top Tier fuels also helped clean existing deposits from engines.
To find Top Tier fuel, look for a Top Tier logo on the pump. Any fuel — regardless of octane, and diesel — can qualify for Top Tier status. Thus it is not necessary to get premium fuel if your car only needs regular. However, if your car requires premium, lower octanes could damage the engine.
The following is a list of Top Tier fuel brands available in the U.S. You can also consult the official Top Tier gas website to find the latest updates, as well as Canadian, Mexican, and South American brands that offer it.
Express Mart (Wisconsin)
HFN - Hawaii Fueling Network
Harmons Fuel Stop
Kirkland Signature Gasoline
MFA Oil Petro-Card 24
Simonson Station Stores
Tobacco Outlet Plus Grocery