Can magnets improve fuel efficiency or descale pipes?
Both of these questions come around fairly regularly. Some companies sell magnets which clip around pipes. Sometimes they are sold for use in hard water areas, where they are supposed to prevent the buildup of limescale. On other occasions they are sold for cars, where they are supposed to increase fuel efficiency. Neither of these claims has ever been substantiated by careful testing, and there is no theoretical explanation for the supposed effects. The advertisers try to make it sound like there is, but its actually just pseudo-scientific eyewash. Note that in some cases installing the fuel magnets according to the instructions will give increased fuel efficiency. This is because the instructions tell you to adjust the carburettor. The result is that the engine runs leaner than it was designed to, causing increased fuel effeciency (based upon mileage), higher production of nitrous oxides (emissions / smog) and a shorter life. The magnet has nothing to do with it. If this worked then
