Gas-Savings Devices: A Road Test Update
As we reported July 4, the preliminary results showed a slight improvement with one device, a decrease in mileage with a second and no change with a third.
We asked Triple A to keep logging mileage so we could check again.
The Three Products
We spent $228 on three products a KOMO 4 News viewer found on the Internet -- a $33 oil additive, an $87 air swirl device and a $108 set of magnets that attach to the fuel line.
Triple A supplied three field trucks that use up to six tanks of gasoline a week, in both city and freeway driving.
Our objective was to test the products as would a typical consumer -- buy, install and compare.
First we had to establish a baseline. That was on June 4.
Results After Two Weeks
After two weeks of driving, the mileage on the three Ford Rangers ranged from a low of 14.8 miles a gallon on the '97 model, which had the air swirl device installed, to a high of more that 20 miles a gallon on the 2001 model, which got the fuel line magnets.
The oil additive went in the '99 Ranger, which started out averaging 18.4 miles a gallon.
Two weeks later, we looked at the preliminary results. The Ranger with the air swirl device had put on the most miles. It traveled 949 miles and averaged 14.96 miles to the gallon.
That's an improvement of nine-hundredths of a mile per gallon.
Worth A $108 Investment?
The Ranger with the fuel magnets went 640 miles and showed an increase in fuel economy of seven-tenths of a mile per gallon.
That's a better improvement than with air swirl, but our experts say not exceptional for our $108 investment.
The truck with the oil additive didn't get driven as much as the others. It went about 220 miles -- and showed a decrease in fuel economy of about two-tenths of a mile per gallon less.
Three More Weeks
For fairness, we continued monitoring for three more weeks.
By July 25 the three Triple A trucks had traveled between 1,100 and 2,000 miles.
AAA master technician Don Beyer says that's sample time to see if the products can produce.
The magnet vehicle, for example, started out getting 20.13 miles a gallon. On July 2, after two weeks of driving, that had risen to 20.18 miles on gallon. On July 25, the number was 20.7 -- almost six-tenths per gallon more. That's about a 3 percent increase.
"Not significant really," said Beyer. "A mile to two miles per gallon might be significant. This is very small."
'No Change Whatsoever'
We were especially curious about the oil additive, since it hadn't had a fair driving time for the preliminary check.
"The vehicle with the oil additive in it started at at 18.45 miles per gallon. It ended up at 18.42 miles per gallon," said Beyer.
"No change whatsoever," Beyer said. "And the vehicle with the air swirl device started out at 14.87 miles per gallon and ended up at 14.25 miles per gallon.
"Actually a decrease, but then, such a small decrease, that that's insignificant as well."
Beyer says a significant improvement would be more like 10 percent -- at the very least more than 1 percent consistently. We didn't get that with any of the three products.
What Really Works
Triple A and other automotive experts say that with today's engineering, modifying your car for better mileage isn't necessary for the typical driver.
They say you'll get the best gas mileage by:
- Keeping your car maintained.
- Using the correct tire pressure.
- Avoiding excess weight in the trunk.
- And avoiding unnecessary braking and acceleration, which wastes gasoline.
For More Information: