Let's start by telling you something you already know: gas prices are at an all-time high. It's also no secret that Jeeps aren't the most fuel efficient vehicles we could drive, yet we do in spite of escalating fuel costs. We constantly see advertisements that promise to increase your fuel economy for only $39.99 or whatever. Well, all this time, we've figured that they were just a bunch of snake oil, but after being inundated with new ads and paying almost $1,000 a month in gas, we decided to get ahold of the various different gas-saving items and test them in our project Jeep, Red.
For comparison sake to your Jeep, Red is our 4.0L '01 TJ with an NV3550, AEM Brute Force air intake, 4 inches of lift, 35-inch tires, 4.56 gears, a rear Detroit Truetrac, front ARB Air Locker, A/C, a Warn 9500i winch, soft top, and rear tire carrier/bumper. We started testing with 115,887 miles on the odometer, and as of press time, have 124,056 miles on it.
For purposes of this story, we rate a "significant" change as anything that gave us a 1 mpg or better average increase. Anything less, we deemed "not statistically significant." After each item was tested, it was then removed and a tank of gas was run through the Jeep before the next test occurred. We present the tests here in the order we performed them.
Claim: Reduces surface tension of fuel droplets, enabling it to burn more completely. As an added benefit, it is supposed to clean carbon buildup from the engine.
In use: Add about 1 ounce of acetone per 10 gallons of gas.
Observed gains: On the first couple of tanks, we saw some decent gains. After two or three tanks of gas, though, we were back to roughly the same mileage we saw before for no statistically significant gain.
We had some really aggressive mud tires on the Jeep and decided to swap them out for a less aggressive all-terrain tire in the same diameter. We didn't expect to see as big of a gain as we did, but we saw about a 1.5-mpg increase.
Claim: "Its airflow dynamics create a swirling, fast-burn effect in the combustion chamber thus creating finer particles (atomized fuel), allowing better flame propagation and more complete combustion."
In use: Put the unit in our air-intake tube, put the intake tube back on the Jeep, and go.
Observed gains: Not only did we see no significant mileage gains, but we felt as if there was a decrease in power; hills along the normal commute to work that we used to be able to pull in Fifth gear, we ended up downshifting into Fourth to maintain speed.
Price: $64.95
Claim: "The strong magnetic charge the EPM [Engine Performance Maximizer] puts into the fuel, air, and coolant gives your fuel a complete and clean burn so that you can take advantage of increased horsepower with reduced operating expenses. Ten-25 percent on average fuel savings, depending on the age of the engine,and an 83 percent average reduction ofhydrocarbons."In use: Apply magnets to the fuel line, coolant hose, and air tube.
Observed gains: Even with magnets on the fuel, coolant, and air intake tubes, we noticed no significant gains with Red.
Price: Not available at press time