For many American drivers, choosing premium gas at the pump is a no-brainer. Even when the vehicle manufacturer recommends regular unleaded gas, drivers often splurge on the high-octane option without really knowing what makes the two varieties different. Most drivers vaguely understand that premium gas improves fuel and engine efficiency in high-performance vehicles, and they mistakenly believe the same holds true for any car.
Drivers may think they're getting a performance boost with premium fuel, but research from the American Automobile Association suggests high-octane gas offers no added benefits for cars that don't require it. Unfortunately, this error in judgement has amounted to $2.1 billion in wasted cash over the last 12 months, according to AAA. While only 16 percent of U.S. drivers own vehicles that require premium gas, roughly 16.5 million drivers overpaid for fuel.
Partnering with the Automobile Club of Southern California’s Automotive Research Center, AAA put premium fuel to the test in vehicles with V-8, V-6 and I4 engines designed to run on regular-grade gas. Researchers compared the horsepower, emissions and fuel economy of vehicles containing regular 87-octane gas and 93-octane premium gas. The premium fuel didn't significantly outperform the regular-grade fuel in any test category, suggesting that high-octane gas is a pointless splurge for many drivers.
As premium gas isn't necessary for cars that use regular-grade fuel, drivers may wonder when it does make sense to pay for the more expensive fuel. Octane is a type of hydrocarbon that ignites at a specific compression level, and gas with more octane can withstand more compression. High-octane gas is used to reduce pre-ignition, which occurs when poor compression causes engine fuel to ignite too quickly. This irregularity leads to "engine knock," and hearing this sound often is a sign that the engine isn't performing efficiently.
Using fuel with the right octane level helps to control combustion and protect the engine from damage. High-performance cars typically need premium gas because their engines have a high compression ratio, and they may ignite erratically if paired with regular-grade gas. However, many of these vehicles also have sensors that automatically adjust the combustion cycle to prevent engine knock.
To be safe, the manufacturer guidelines are the best way to find out if the car needs high-octane fuel. John Nielsen, the Managing Director of Automotive Engineering and Repair for AAA, advises drivers to think twice before choosing the costlier option.
"Drivers see the 'premium' name at the pump and may assume the fuel is better for their vehicle. AAA cautions drivers that premium gasoline is higher octane, not higher quality, and urges drivers to follow the owner's manual recommendations for their vehicle's fuel."
In some cases, a car that uses regular-grade fuel may benefit from premium fuel if the engine starts to wear and its compression level increases. However, most drivers who still want premium-quality fuel for their vehicles should consider switching to a high-quality brand instead of needlessly upgrading to high-octane gas, recommends AAA. TOP TIER fuels satisfy industry standards for efficiency and cleanliness, making it easier for drivers to keep their engines running smoothly for years to come.