The Tornado Fuel Saver is a device marketed on late-night infomercials. It claims to be able to increase both fuel economy and performance, by improving the mixture of fuel and air in your car's engine.

It is a scam.

The device itself is a steel cylinder that one puts in the air intake hose of their fuel-injected vehicle, or inside of the air cleaner housing on a vehicle with a carburetor. This cylinder has little angled blades inside, like those on a fan. According to the folks at LL&C Dealer Services, LLC, the Tornado swirls the air headed towards your engine, thereby allowing it to more readily mix with fuel.

When I saw the infomercial, it seemed quite fishy, so immediately I entered "tornado fuel saver" into Google Groups, and my suspicions were confirmed. Any kind of obstruction in the airflow, swirly or otherwise, will not help fuel economy. It will decrease airflow, which will cause one of two things to happen: your engine will run rich(er than it's supposed to), thereby wasting fuel, or the fuel injection computer (which does not like to be messed with) will reduce fuel flow, thereby reducing performance. This is probably where the fuel saving claim comes in, but the saving is minute if it exists at all, and it comes at the cost of reduced performance.

The fuel saver retails for $70, plus $11 S&H, and some vehicles "require" that you purchase TWO of these things! I believe a fellow on rec.autos.tech put it best when he said that the only possible benefit is that your car might get .0000000000005 more miles per gallon because your wallet is .00004 ounces lighter.

    Sources:
  • TornadoFuelSaver Fuel Saving Device - Increase Gas Mileage and Horsepower! - http://www.tornadofuelsaver.com
  • rec.autos.tech "Tornado Fuel Saver ????" -
    http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&oe=UTF-8&safe=
    off&frame=right&th=bf187b8a0b8afadf&seekm=91ofns%24eq4%241%40nnrp1.deja.com#link1

    Sorry for the long URL. It's result #1 when you type "Tornado Fuel Saver" into Google Groups.