Are those magnetic devices you can attach to a fuel line any good for fuel economy?

Dear Car Talk

Dear Car Talk | Jun 01, 2002

Dear Tom and Ray:

I saw a banner ad on a Web site (not yours) for a product called "FuelMiser." This is a magnetic device that is attached to the fuel line. It supposedly conditions the fuel to make it burn more efficiently. I read on and on about the science of how it works. I'm not an engineer, but the idea of the hydrocarbons being magnetically straightened out moments before they get burned sounded a bit dubious. On the other hand, spending $50 to achieve a 10 percent to 20 percent increase in fuel economy and decrease smog at the same time sounds great to me. But I would certainly like some independent validation of these claims. Your esteemed opinions, please? -- John

RAY: There's a certain trick to selling stuff like this, John. First, you have to have a somewhat believable scientific theory upon which to base your product. And these guys have that.

TOM: They claim that the molecules of gasoline are not ideally organized when they come down the fuel line. And that their magnet organizes the H's and C's so they burn more efficiently.

RAY: And you've never seen molecules of gasoline, right? So what do you know about how they're organized? They might live in group houses, for all you know. So it sounds pretty good, right?

TOM: And then you need to have the proper numbers. The right price used to be $19.95. But with inflation, it's now $49.95. That's the amount a person can spend without consulting a spouse. Or giving up HBO. It's a price at which you say, "Well, even if it doesn't work, it's not the end of the world."

RAY: Then you need the right "performance" numbers. Ten percent to 20 percent improvement is the proper range. If they promised to double your mileage, you'd know it was bull. But 10 percent or 15 percent? Sure, you can buy that.

TOM: It's also a number that you can achieve through the placebo effect. In other words, after you install this thing, you follow the other "gas-saving tips" that come in the box -- like accelerating gently, driving slower, taking the bus and not warming up your car -- and lo and behold, your mileage gets a little better.

RAY: You might have figured out by now, John, that we think this thing is a complete waste of money. I actually tried one in my truck, and I didn't notice any difference in mileage.

TOM: But he did, however, have a new place to store his paper clips -- on the magnet under the hood -- so it wasn't a total loss.

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