There is a huge array of options when it comes to filling up your car. Everyone wants to keep their vehicle in top shape and choosing the right fuel seems paramount to a healthy car. One of the most prominent gasoline retailers is Shell, but is Shell gas good?
Shell gas is an excellent option for your vehicle. As a member of “Top Tier Gasoline” Shell gas does offer significant engine health benefits over no-name generic brands. However, all brands of gas must meet at least the same minimum industry standards.
In this post, we’ll look at Shell gasoline in a little more detail. We’ll look at what Top Tier gasoline is, why it’s better for the health of your engine. We’ll look at what makes Shell different, we’ll also look at what octane rating is and why it’s important to your vehicle.
What are Fuel Additives?
It is uncommon for an oil refinery to only provide gasoline to one specific brand. As such, multiple gasoline brands can receive the same gasoline from the same refineries. The fuel that Shell is receiving might be the same fuel that Exxon or Mobile is receiving. The difference between each brand, however, is their mix of fuel additives.
Gasoline on its own can wreak havoc on the precise engineering of modern engines, particularly when it comes to fuel injectors and intake valves. Carbon buildup in these locations can lead to irregular fuel injection into the cylinders, leading to reduced power and fuel economy.
To combat this, gasoline companies mix in their own proprietary blend of additives to make the fuel their own. Broad categories for these additives include both fuel stabilizers as well as detergents to prevent the build-up of carbon deposits throughout the engine.
Is Shell a Top Tier Gasoline?
Top Tier Gasoline is an initiative started between various automakers and fuel retailers to uphold higher gasoline standards, of which Shell is a member.
As fuel injection technology evolved to be more precise through the 80s, issues concerning clogging began to arise. An inadequate amount of fuel additives was found to be the cause and automakers set out suggestions for higher levels of additives.
Full List of Top Tier Gasoline Companies (November 2021)
- 76
- ARCO
- Aloha
- Beacon
- Break Time C Stores
- Breakaway
- CITGO
- Cenex
- Chevron
- Conoco
- Costco Wholesale
- CountryMark
- CountryMark PLUS
- Diamond Shamrock
- Express Mart
- Exxon
- Fast Fuel
- HFN – Hawaii Fueling Network
- Harmons Fuel Stop
- Hele
- Holiday
- Irving Oil
- Kirkland Signature Gasoline
- Kwik Star
- Kwik Trip
- MFA Oil
- Marathon
- Metro Petro
- Meijer
- Mobil
- Ohana Fuels
- Phillips 66
- QT
- QuikTrip
- Ranger
- Ranger Fuel
- Ranger Mustang
- Ranger Stallion
- Ranger Thoroughbred
- Reeder’s
- Road Ranger
- Rutter’s
- Shamrock
- Shell
- Simonson Station Stores
- Sinclair
- Sunoco
- Texaco
- Tobacco Outlet Plus Grocery
- Valero
- Value America
- WOW
- Win Win
This would be followed by some fuel retailers, but not all. It would not be until 1995 where the EPA would set regulations for the minimum amount of fuel additives that need to be included.
The problem with these regulations was that these new standards were in the context of vehicle emissions instead of increased engine life. As such, retailers that previously had higher levels of additives would cut levels down to just meet the minimum requirements imposed by the EPA.
About a decade would go by before a group of automakers would get together to set standards on what good fuel should be and give them the ranking of “Top Tier”. The participating automakers include BMW, GM, Ford, Honda, Toyota, Volkswagen, Mercedes-Benz, and Audi.
To be certified Top Tier, the gasoline must pass a series of performance tests. The tests end with the engines being taken apart and checked in various key locations for carbon deposits. If it is of a satisfactory amount, and the retailer agrees that all their fuel grades meet those standards, then it’s certified as Top Tier.
Is Top Tier Gasoline Actually Better?
As with a lot of things in life, people may be hesitant to believe the benefits of something like Top Tier gasoline and instead may chalk it up to a gimmicky marketing tactic. Thankfully, third-party studies have been done to illustrate that these fuels do indeed help keep an engine healthier.
One such study was done by the American Automobile Association. They picked three fuels randomly from Top Tier gasoline retailers and then three fuels from basic sources. They used each fuel in a different engine that was continuously run for 100 hours to represent 4,000 miles of real-world use. Afterward, these engines would be taken apart and examined to measure the total buildup of carbon deposits.
The results were significantly in favor of Top Tier fuels. On average there were 19 times fewer deposits on the injectors, intake valves, and combustion chamber when compared to regular gasoline. Excess carbon buildup was seen to cause a 2-4% loss in fuel economy and misfires, as well as a rough idle.
In the same study, AAA ran engines on basic fuel for 10,000 miles and then examined them for carbon buildup. These engines would then be reassembled and run another 5,000 miles with Top Tier fuel. After another disassembly, it was found that the detergents found in Top Tier fuel were able to actually reduce the carbon deposits by anywhere from 45 to 72 percent.
Best of all, the Top Tier fuels were observed to be on average only three cents more expensive than the basic fuels over a 12-month period.
What are Octane Ratings?
Taking a trip to a Shell gas pump, you will be presented with three options when choosing your fuel. These are different octane levels and will more often than not be separated into 87 (regular), 88-90 (midgrade), and 91-94 (premium).
While most vehicles will be fine with regular grade fuels, you might have noticed that performance-oriented vehicles will often recommend that their owners use higher grades. This, however, is not due to higher grades containing more energy. Instead, higher grade fuels are more stable and will prematurely combust at a lower rate.
In an internal combustion engine, fuel is compressed in a cylinder and then ignited in a controlled manner by a spark plug. Gasoline, however, is a volatile substance and the heat and pressure of an engine on its own can cause the gasoline to detonate without the use of a spark plug. This can throw the engine off for a split second and cause a knock.
Modern engines lookout for these knocks and try to compensate for them to reduce the chance of engine damage, but it still can result in a penalty for both performance and fuel efficiency.
To achieve the higher power found in performance vehicles, the engines have higher compression ratios than regular vehicles, putting the fuel under further pressure and increasing the chance of premature detonation.
As such, those automakers will recommend that their owners opt for more stable fuel grades to better deal with the higher pressures. Your vehicle won’t instantly break if you use lower than recommended grades of fuel, but you will most likely lose out on performance and long-term engine health.
Sometimes, gasoline retailers such as Shell will add even more additives to their higher grade fuels, but if your vehicle only recommends the bottom grade, then it’s rarely worth the jump to higher-priced grades.
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John Cunningham is an Automotive Technician and writer on Rustyautos.com. He’s been a mechanic for over twenty-five years and has worked for GM, Volvo, Volkswagen, Land Rover, and Jaguar dealerships.
John uses his know-how and experience to write articles that help fellow gearheads with all aspects of vehicle ownership, including maintenance, repair, and troubleshooting.