TAMPA - Gas prices are up more than a dollar from this time last year, according to AAA. One year ago, the nationwide average for regular gasoline was $2.79, but today, the average is $3.83.
While gas prices have dropped in recent weeks, this summer could end up being a costly one compared to last year. The brand of gas you buy could potentially save you money and impact your car’s performance. The I-Team tested the most popular brands of gas to find out how they affect your car.
Two weeks ago, D.R. Musselman got the Porsche he’s always wanted.
“It’s a 2004 Porsche 911 Turbo. It’s great. A lot of fun, a lot of power,” Musselman said.
Musselman wants to take good care of his car. He takes it in for maintenance and he only uses premium gas. But what about the brand of gas? Exxon, BP, Shell, and all the other types of fuel each use their own formula, with unique additives. One major additive of gasoline is detergent.
Gasoline detergent is a lot like your laundry detergent, cleaning your engine and preventing deposits from forming on critical engine parts.
Auto experts say more detergent can mean improved performance, cleaner emissions, even better gas mileage. So, which gasoline has the most detergent?
Working with our partners at the Scripps Howard News Service, we collected one-gallon samples of regular unleaded and premium fuel from 8 national brands across 3 states. We took our samples to Paragon Laboratories, an independent, certified testing facility near Detroit, to find out if all brands are created equal when it comes to detergent.
“The most important thing for consumers to do is to use the same brand of gas. One of the worst things you can do is to go from brand to brand to brand, getting the cheapest stuff you can find. That will accelerate the buildup of deposits because you’re dealing with vast differences in types of detergent,” said Tony Molla of the National Institute for Automotive Service Excellence (ASE).
Molla says if you repeatedly fill up with gas that doesn’t have enough detergent, deposits can build up, causing your engine to burn more gas.
“As the deposits build up, they tend to attract more deposits. So it’s very much like a process that the longer it goes untreated, the worse it becomes,” Molla said.
Paragon performed unwashed gum tests -- the same test automakers use when spot-checking to see if gas meets their standards. Scientists boiled each sample and measured the residue left behind. The more residue, the more detergent, which could equal better gas mileage.
In our test of regular unleaded gas, Exxon had the highest level of additives, with 20 milligrams of residue per 100 milliliters. BP and Shell followed close behind, while Marathon, Citgo, Pilot, and Speedway samples each had less than half the amount of detergent found in the top three brands.
“Obviously the more detergent, the more efficient job it’s going to do of cleaning the valves,” Molla said.
You pay a premium for gas that’s 92 or 93 octane, and in our test, Shell leads the pack with 31 milligrams, followed by BP and Exxon. We found the lowest levels of additives at Speedway, Mobil, Citgo, Marathon, and Pilot. Pilot’s 8.8 milligrams is three times less than Shell. But in a statement, company vice president Alan Wright told us, “Our gas blends meet EPA requirements. We don’t put in extra.”
Not everyone believes detergent in gasoline makes a large difference. Alan Saad of Vortex Motorsports in Tampa has worked on cars for more than 30 years. He says low detergent fuel most likely won’t cause serious problems because engines run cleaner nowadays.
“In the mid-80s, it was a huge problem with intake valves, injectors,” Saad said.
But Saad agrees that if you plan on having a car for a long time, higher detergent gas can be a good idea to help prevent deposit buildup and maintain your car’s performance.
D.R. Musselman wants to keep his Porsche in good shape for years to come, and he’s willing to pay a few extra dollars for his fuel.
“I think I probably would change if I knew that information, because I think it probably does make a difference,” he said.
All of the experts we spoke with say the most important thing for consumers is to choose one brand of gas and stick with it. Changing from brand to brand can lead to those deposit buildups that can cause problems for your car, including reduced gas mileage.
The chemical tests conducted by Paragon Laboratories show widely different levels in gas samples collected on March 10.
BP 87 Octane ... 17.2 milligrams per 100 milliliters
BP 93 Octane ... 26.4 milligrams per 100 milliliters
Citgo 87 Octane ... 6.0 milligrams per 100 milliliters
Citgo 93 Octane ... 9.4 milligrams per 100 milliliters
Exxon 87 Octane ... 20.0 milligrams per 100 milliliters
Exxon 93 Octane ... 21.2 milligrams per 100 milliliters
Pilot 87 Octane ... 5.8 milligrams per 100 milliliters
Pilot 92 Octane ... 8.8 milligrams per 100 milliliters
Shell 87 Octane ... 16.2 milligrams per 100 milliliters
Shell 93 Octane