Fuel-Saving Products
From SkepticWiki
[edit] Definition
Numerous fuel-saving products have been on the market for twenty-five years or more, no doubt spurred on by the energy crisis of the 1970s. With the high gas prices in wake of the second Gulf War and the Hurricane Katrina disaster, these devices are making a comeback.
There are many such products on the market; many claim to be able to use magnets to improve the combustibility of the gasoline (basically, Magnet Therapy for your car). Others claim to improve airflow. Still others are chemicals added to the gas or oil tank. Gas savings of 20% or more are claimed.
[edit] Testing
Most of the evidence for positive results for these devices are mere anecdotes. Scientific testing has yielded less impressive results. The EPA has tested hundreds of devices, and the few that showed any improvement at all showed such a minuscule improvement that you would have to drive the vehicle for its entire lifespan in order to save enough gas to regain your initial investment. Some were even shown to have a detrimental effect on emissions.
The claims behind most of these devices are pure pseudoscience. There is no known mechanism for magnets to change the molecular structure of gasoline in any way at all, much less a way that causes a cleaner burn. The fuel-to-air mixture is already engineered to run at its optimum level (in fact, some of these airflow devices actually reduce efficiency). Also, modern fuel injectors (not in place when many of these devices were first offered) use computers to control precisely the amount of gasoline injected, so the car will be consuming the correct amount of gasoline for the amount of air and the current operating conditions no matter what.
Of course, with hundreds of these devices on the market, it is possible that one or two of them might be able to increase fuel economy to such a degree that it makes the investment worthwhile, but with so many ineffective devices seeing success in the market, the principle of caveat emptor—let the buyer beware—certainly should apply. Remember, if a device really worked, any automaker would want their cars to have it as a selling point (more horsepower for less fuel).
If you really want to improve your vehicle's fuel economy, the standard suggestions of using overdrive and cruise control, avoiding fast acceleration and unnecessary idling, coasting to stops rather than suddenly stopping, and keeping your tires inflated to the recommended pressure are proven effective while requiring no cash outlay.
