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I am a vehicle owner who prizes a clean engine. I own a truck, a passenger car and a Harley Davidson motorcycle. All my vehicles are equipped with fuel injection. So, I don’t pinch pennies when it comes to buying gas. To keep my engines operating at peak efficiency, I use only TOP TIER™ fuel at the pump. You may wonder: What is TOP TIER™ fuel? And does it keep engines clean?

What is TOP TIER™ fuel?

All fuel contains some level of cleaning detergents, but the Federal Government only mandates that gasoline contain the Lowest Additive Concentration (LAC) of detergents*. This LAC is a tiny (insufficient) amount. At this level, it isn’t enough to keep normal fuels clean.

Because of this, many OEMs and fuel retailers support the use of TOP TIER™ fuels**. TOP TIER™ fuels contain more detergents than the LAC. So they should be enough to keep your engine clean, right? Well, not exactly.

The investigation begins.

I was talking with a fuel chemist friend (we should all have one) about TOP TIER™ fuels. He said to me, “If you think TOP TIER™ fuel is keeping your engine clean, better think again. What you believe is not actually what is true.”

What did he mean by that?! And why did he have to say it like my college philosophy professor? I had to know! First thing I did was read the TOP TIER™ Performance Standard***. I read it once. I read it twice. And I didn’t find anything too suspicious. I called my friend and asked him where the smoking gun to TOP TIER™ fuel was. He told me to read Section 4.3.2.3 Demonstration of Performance.

The investigation continues.

The Demonstration of Performance is a bit hard to decipher, but, after some study, I couldn’t believe what I saw: 

TOP TIER™ fuel can introduce up to 40% MORE combustion chamber deposits than fuel that doesn’t contain TOP TIER™ detergents.

How can that be?! My fuel chemist friend explained that TOP TIER™ fuel uses lower cost, less stable fuel detergents. And once these detergents are heated in the combustion chamber they basically fall apart. Then they leave carbon deposits inside your engine. Now isn’t that an ironic twist? 

The investigation spirals.

I continued reading and found a further concern with using TOP TIER™ fuel. The detergents in the fuel can keep your intake valves from sticking. Hooray! But only if you use two or three times the amount of detergent than what’s found in the fuel. Boo! Obviously, I can’t control how much detergent is in each gallon of gas.

What’s the solution?

I’m not up here on my soapbox telling you not to use TOP TIER™ fuel. Regardless of whether you use TOP TIER™ fuel, your engine is likely getting dirtier and dirtier with each tank of gas. It’s science. The best solution I can give you is the one I trust. Use a combustion chamber cleaner to derail that carbon relocation program.

As for me, I’ll be saving my money at the pump from now on.

by Michael Belluomo
Technical Service Manager
30 years of experience in fuel and lube technologies

*https://www.federalregister.gov/documents/2014/04/30/2014-09856/proposed-information-collection-request-comment-request-regulation-of-fuels-and-fuel-additives

**https://www.consumerreports.org/car-maintenance/study-shows-top-tier-gasoline-worth-extra-price/

***https://www.toptiergas.com/deposit-control/