In a time of rising gas prices (well, actually falling at present but still more expensive than last year), many consumers are searching for ways to cut fuel costs. One eye-catching options appears to be so-called water for gas, turning the H2O from your tap into an endless fuel source.

But you'd better not put said water directly in your gas tank. That's a quick way to kill combustion in your internal combustion engine and earn a trip to the repair shop.

That's not what these outfits are peddling of course. They're selling kits that allow people to electrically or chemically separate the H2 from the O in water and then use said H2 as a fuel additive. And one man in Norfolk has used such a kit to extend the range of his Chevy Avalanche.

This makes more sense as it is the hydro in hydrocarbons like oil that provides the go in your vehicle (and it is the carbon that combines with oxygen via burning to form CO2, the most ubiquitous greenhouse gas warming the planet). By adding more H2 it is possible to extend the gas mileage of a vehicle.

But only under certain conditions. Most internal combustion engines, which, after all, are highly engineered pieces of machinery, are tuned to specific fuels (which is also why premium gasoline won't deliver benefits to an engine not designed for it). Although BMW and others have designed cars that can switch back and forth from burning hydrogen to burning gasoline, most cars aren't that capable. And any savings on fuel must be carefully weighed against the cost of the kit, which can run to thousands of dollars for an electrolyzer—a machine that splits water with electricity (which is also rising in price, by the way).

So be careful what you put in your gas tank. A penny saved at the gas station could turn into a dollar spent at the garage.

Credit: © Baris Simsek /