Gas prices fluctuate more than the weather in Mississippi, so it’s important to know which type of gas to feed a vehicle to get the best value.
According to a study by the American Automobile Association (AAA) in 2016, 63% of drivers believe there is a difference in quality of gas, but only 12% actually purchase gas based on which detergent additives are inside. Each gas company has a different detergent formula that makes up its brand.
The primary motivations for buying a particular gasoline, AAA reported, are location, convenience and price.
There are two broad types of gasoline: Top Tier and non-Top Tier. AAA reported that Top Tier is generally better for an engine over the long term.
In the test it conducted, an engine was operated for 100 hours to simulate 4,000 real miles of use. Six fuels were randomly selected — three from Top Tier companies and three from basic companies. Top Tier gas had 19 times fewer carbon deposits on injectors, intake valves and combustion chamber than regular gas.
Over a 5,000-mile interval, Top Tier gas reduced intake valve deposits by 45% to 72%. The variations depended on the types of detergent used by different brands.
Over the course of 12 months, AAA found an average price difference of only 3 cents between the two types of gas.
Several major gas station companies utilize Top Tier gasoline, including BP, Chevron, CITGO, Costco, Exxon, Marathon, Mobil, Shell and Texaco.
Then there’s the question of regular versus premium gas. The truth is, if a car doesn’t require or recommend premium gas, it’s best to save the extra pennies.
AAA estimates that people waste over $2 billion a year putting what they think is better gas into cars that only require regular.
The numbers on gas pumps, such as 87, 89, 92 and 93, are octane ratings. The lower numbers ignite the gas with the least amount of compression, and the higher take more compression in higher-performing engines.
The fuel is ignited with a spark from the spark plug. If the fuel lights too quickly before the spark plug can work its magic, a rattling or pinging sound will occur in the engine, known as “engine knock.” This isn’t a big deal if it happens only occasionally, but over a long period, it can cause engine damage.
“If it doesn’t say ‘required,’ it’s fine to go with the lower grade,” Jason Kavanagh told the New York Times. Kavanagh is the senior vehicle test engineer at Edmunds.com, a website for car-shopping.
The New York Times also asked AAA engineers to run numbers for whether premium gas makes a difference in miles per gallon. In short, it doesn’t.
They reported that mileage improved 2.7% and horsepower increased 1.4%, but premium prices averaged 20% more than regular. They said the improvements “would not nearly offset the price difference between regular and premium.”
On the subject of ethanol, gasoline with it is a cleaner fuel than gasoline without it, according to Digital Trends. However, the more ethanol in the fuel, the worse the fuel economy will be. Digital Trends reported that gasoline with 10% ethanol yields about 3% less fuel economy than straight gas.
Ethanol-free gas costs much more and may get better mileage, but it doesn’t offset the extra cost.
Ethanol in gas in the United States is mandated by Congress, starting with the 1990 Clean Air Act, followed by the 2005 Renewable Fuel Standard.
In 2007, the renewable fuel standard goals were raised to 36 billion by 2022. In 2014, 13 billion gallons of ethanol were mixed together with U.S. gas every year.
In short, the best course of action is to follow the fuel guidelines listed in a car’s user manual.
•Contact Kerrigan Herret at 581-7233 or kherret@gwcommonwealth.com.
