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How Top Tier Street Fuels Keep Your Engine Cleaner

by Grassroots Motorsports


Posted on 10/17/2024 at 9:00 AM


Gasoline fluid

 

 

When you stop to fuel up your street car, what’s the most important draw? Price? Location? Points? Clean toilets? Artisan sandwiches sporting the perfect amount of lettuce?

Probably not the gasoline itself, right? After all, aren’t all pump fuels the same?

Well, no.

Some gasolines qualify as Top Tier. These fuels meet the performance standards set forth by a group of vehicle makers: BMW, General Motors, Stellantis, Ford, Honda, Toyota, Volkswagen, Mercedes-Benz and Navistar.

“The Top Tier gasoline program was started by auto manufacturers who wanted cleaner fuels to reduce mechanical failures of their vehicles,” explains Zachary J. Santner, senior specialist of quality at Sunoco.

What makes these fuels so special? Detergents.

“Gasolines with higher amounts of detergent can prevent gunk and deposits from building up on valves, pistons, fuel injectors and intake runners,” Santner continues. “A clean engine will perform better, get better mpg and lower emissions.

Top Tier fuels come from the same refineries as all other fuels but are given a higher treat rate of detergent at the terminal level. A Top Tier fuel like Sunoco can help keep your engine cleaner than a fuel that meets the government’s lowest additive concentration of detergent.”

In 2016, AAA set out to test that claim, running both Top Tier and non-Top Tier fuels through a 2.3-liter Ford engine mounted in a dyno cell. Each fuel was run for 100 hours, simulating about 4000 miles of real-world driving. After each fuel sample, the engine was disassembled so that deposits could be measured.

The full report covers 33 pages–you can find it at aaa.com–but here’s its take-home message: “The test engine operated on a Top Tier gasoline averaged 19 times fewer intake valve deposits than when it was operated on non-Top Tier gasoline.”

Not all brands carry the Top Tier designation, but Santner notes that all of Sunoco’s pump products do, no matter the grade, the location, or the time of year.