Magnets & Catalysts
These types of devices supposedly "line up the fuel ions" in order to make the fuel burn more completely and efficiently. They wrap a magnet around the fuel line and as the fuel passes by, it changes the burn properties of the fuel. The only problem is, magnets have no effect on fuel or the fuel "ions". I tested one such product that sold for over $300.00!!! The other type is a fuel catalyst. This type fits into the fuel line and as the fuel runs through it, special materials cause the fuel to "improve fuel performance in the areas of decreased fuel consumption reduced exhaust emissions and restored fuel properties."
Southwest Research Institute San Antonio Txtardec Fuels And Lubricants Research Facility (SwRI/TFLRF) tested three such devices and found "Under the conditions tested no fuel economy benefit was observed for the baseline device".
Next time around I will go into some other types of devices. but before I go let me leave you with this: the best way to improve gas mileage is to keep your engine well-tuned and check your tire pressure every time you fill up.
Source: Fuel saving device
