A fuel is a TOP TIER™ Approved Gasoline or TOP TIER™ Approved Diesel if it contains an additive package that has been demonstrated to meet the requirements set forth in the TOP TIER™ Performance Standards when used at the minimum approved concentration and has been approved for use in TOP TIER™ Licensed Brands by the sponsoring Automotive or Heavy-Duty Vehicle Manufacturers. The Fuel Retailer has also agreed to other conditions when they become licensed, such as displaying the logo at the site (either on the dispenser or at the fuel point-of-purchase) and allowing random sampling for quality monitoring.
The TOP TIER™ Performance Standards were created to promote better fuel quality, thus maintaining engine performance so that engines run as designed.
Each of the programs, TOP TIER™ Approved Gasoline and TOP TIER™ Approved Diesel, was created to address the unique requirements of modern gasoline and diesel powered engines and to allow for incorporating new requirements as engine technology evolves.
The TOP TIER™ Gasoline Performance Standard requires the use of additives tested and shown to minimize the build-up of carbon deposits that can reduce fuel economy, increase emissions and cause problems such as hard starting, hesitation and stalling. The TOP TIER™ Gasoline Performance Standard also prohibits the use of organometallic additives in gasoline that are known to damage emissions aftertreatment systems.
The TOP TIER™ Diesel Performance Standard requires the use of approved additive packages shown to reduce internal and external injector deposits, and includes specific modern-day engine requirements for:
1) lubricity to decrease wear on pumps and injectors,
2) fuel stability to minimize oxidation degradation that can result in bacterial growth in gas tanks and sludge in engines, fuel injectors and fuel filters, and
3) particulate and water contamination to reduce fuel delivery system plugging and corrosion.
There are many factors that influence fuel quality. For gasoline powered engines, the requirements for TOP TIER™ Approved Gasolines primarily address fuel quality issues related to engine cleanliness and prohibit the use of organometallic components in fuel that could cause harm to emissions aftertreatment systems.
For diesel powered engines, the requirements for TOP TIER™ Approved Diesel address quality issues related to injector deposits, wear on pumps and injectors, fuel stability, and particulate and water contamination.
TOP TIER™ licensed gasoline marketers are required to use TOP TIER™ Approved Fuel for all grades of gasoline sold at their stations.
Because of logistical issues unique to diesel fuel supply, the TOP TIER™ Approved Diesel Program allows fuel marketers to offer TOP TIER™ Approved Diesel at select stations only. In these cases, the TOP TIER licensed diesel marketers are also required to use TOP TIER™ Approved Fuel for all grades of diesel sold at their participating stations.
Your owner’s manual may also make recommendations beyond the use of TOP TIER™ Approved Gasoline or Diesel.
Fuel delivery trucks are typically equipped with separate compartments allowing them to carry different fuels on the same load to various customers.
Retail outlets enrolled in the TOP TIER™ Program are contractually committed to selling fuel that meets the TOP TIER™ Performance Standards. This means they are supplying fuel that contains an approved additive at the right concentration that does not contain other additives known to harm engines. In addition, TOP TIER™ licensed retailers are monitored for quality through unannounced random auditing.
Please note that stations can enroll in the gasoline and diesel program separately, so always look for the TOP TIER™ Approved Gasoline or Diesel logo.
All TOP TIER™ Licensed Brands are formulated to meet the stringent requirements for TOP TIER™ Fuels. We recommend any of the fuel brands enrolled in the program. Please check your vehicle owner’s manual for other important fuels information.
TOP TIER™ Approved Gasoline Brands
TOP TIER™ Approved Diesel Brands
Formulations are proprietary to each fuel brand, however, each TOP TIER™ Approved additive package is screened for compliance to the requirements set forth in the TOP TIER™ Performance Standards.
TOP TIER™ is a higher standard of fuel, which can benefit all internal combustion engines, so you can feel confident using it in any gasoline or diesel fuel powered vehicle.
The TOP TIER™ Program does not have any direct data regarding the fuel sold on military bases. These stations are not enrolled in the TOP TIER™ Program. We encourage you to use their website “Contact Us page” to let them know that TOP TIER™ Fuel is important to you.
Some convenience stores do sell fuel brands that are TOP TIER™ licensed and meet the stringent requirements set forth in the TOP TIER™ Performance Standards. You can find the list of TOP TIER™ Approved Gasoline Brands here, and Diesel Brands here. If the brand of gasoline or diesel on the signage or the dispensing pump is not on our brand list, the fuel is not licensed to be TOP TIER™.
Although the technology and mechanical equipment for direct fuel injection differs from port fuel injection or carbureted fuel systems, the short answer is the “keep- clean” effect in these fuel systems may not differ greatly. The data and information that the sponsoring engine manufacturers have is not available in the public domain, but AAA conducted an independent investigation comparing the minimum EPA detergent levels to TOP TIER™ Approved Gasoline. The full report is available for free download here. AAA did a great job showing where in the engine you can benefit from gasoline meeting the TOP TIER™ Performance Standard and even commented on GDI engines (see section 2 of their report on pages 9 and 10; and the sub-section on emissions found in section 5.3 – page 19).
TOP TIER™ Approved Gasoline is highly recommended for consistent use in your vehicle. If TOP TIER™ Approved Gasoline is not readily available in your area, please refer to your Owner’s Manual for recommendations on the use of a fuel system treatment to keep your engine fuel deposit free and performing optimally.