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Fuel Saving Devices – Are They For Real?


(Photo by Scott Barbour/Getty Images)

A few years ago, I was approached by a strange man on the street who started chatting and told me all about some stick sort of device he put in his car engine to save him fuel and it was absolutely amazing, blah, blah, blah, and would I like to come to his house and have a look at it?  Needless to say, being a smart woman, I did not go off to the home of a strange guy who said he had a stick that did amazing things he wanted to show me…  I thought no more about this encounter, especially as I discovered later that this guy was the local loony.

However, I have since discovered that devices that can be attached to car engines to supposedly improve the fuel efficiency aren’t the ravings of a lunatic and aren’t the motoring equivalent of “Would you like to come upstairs and see my butterfly collection?”  They are out there on the market, with several made right here in Australia and with lots of people raving about them.  However, are these people right to rave about them?

The first type of device is indeed a stick sort of thing – guess I owe that guy an apology for doubting him but I still wouldn’t go round to his place to have a look at it.  This claims to be a type of catalyst that cleans up the fuel so there aren’t the little gummy particles and other flaws that don’t burn properly during the brief flash of time that the fuel is in the combustion chamber.  In the ordinary way, these large unburnt particles would simply be coughed out in the exhaust system and wasted.  By dissolving these particles into smaller bits, the manufacturers claim that you’ll save fuel because you’re actually using what you’ve already paid for rather than wasting it. Well, that’s what they say, anyway.

Turns out their claims about catalysts may not be all that good.  The red flags went up for me at one site when they claimed that fuel will get mould and bacteria in it over time.  Considering that petrol and kerosene rip living cells to shreds – which is why you should be careful not to get it on your hands and why petrol used to be used to kill head lice – I didn’t quite swallow this one.  Secondly, a catalyst is something that prods a sluggish, reluctant reaction into happening.  The combustion of fossil fuels isn’t exactly a sluggish reaction for a start – quite the contrary.  Lastly, dissolving chunks of grease isn’t anything to do with catalysis (and petrol dissolves grease anyway).  A number of them have been banned or severely reprimanded for making misleading claims.

The second main type of fuel saving device consists of a sort of fan thingummy that changes the way that air flows into the combustion chamber, meaning that those nasty big gummy particles get broken up into fine droplets so that they burn cleaner.  It supposedly makes the air swirl around in the combustion chamber in a sort of vortex shape, which apparently saves fuel.

There is a third type of fuel saving gadget that involves magnets, which are claimed to line up something in the molecules so they burn better.  However, as we all probably learned back when we were kiddies, magnets only work on metal!  If there’s metal in your fuel, something’s very wrong with your car.  Avoid these things.

A bit of prodding around on the internet suggests that most reputable motoring organisations tend to be very, very sceptical about these gadgets and that most of the claims of great savings come from testimonials and not from properly carried out scientific tests.  OK, the claim that parachutes save lives hasn’t been subjected to a proper scientific test either, so simply going on testimonials and empirical evidence isn’t always bad (Smith and Pell, 2003,   I don’t want to be close-minded but I don’t want to be a gullible idiot either, so we’d all like to hear from people who have tried them.  What has been your experience?  Have you managed to save fuel or have you been sucked in by a scam – and with which products?

For those who are interested in saving fuel and want to do things the more conventional way, the following devices are guaranteed and won’t cost you anywhere as near as much as those gadgets in the long run:

  • a clean air filter, changed when you’re supposed to do it
  • tyres inflated to the right pressure
  • your right foot, applied lightly, rather than heavily

And always be as cautious about the claims of device manufacturers as you would be about strangers on the street trying to get you to come back to their place. Some may just be friendly new neighbours but…