As has happened before, with gas prices continuing to climb, the demand for improved fuel economy will increase as well, and all manner of improvements and upgrades that promise to help get better mileage will be touted. Some offer real benefits; others are pure snake oil.

An improvement that offers both improved mileage and increased horsepower seems counterintuitive at first. After all, the tradeoff that hybrids and other economy vehicles offer seem to be one of reduced horsepower and acceleration in exchange for improved fuel economy. So how can you have both?

The Pulse Plug is a replacement spark plug that incorporates a capacitor (an “integrated circuit” according to the manufacturer) to increase the power of the spark that ignites the fuel. The manufacturer claims increases of 6 to 8 percent (which works out to about an extra 3 MPG for a Toyota Prius). While it would be misleading to draw a direct connection between the power of the spark and the power from the engine, after all, it’s not the spark that is propelling the vehicle, any more than the temperature of the match determines how hot the barbecue will be. But could a stronger spark provide increased power through a more complete combustion of the fuel? If so, then, at least theoretically, less fuel would be needed for the same level of power - more complete combustion would be cleaner (less unburned hydrocarbons through the tail pipe as well as less fuel used overall).

I’m not prepared to offer judgment about this one. The test results from several vehicles are varied, and in some vehicles, the improved performance was fairly slight. The testing procedure being reported is the manufacturer’s own method, rather than an independent third-party test, which always adds a degree of skepticism to any results. In general, the results seemed to show greater fuel economy improvement with smaller engines (VW Jetta GLI, 1.8L Turbo; Honda S2000, 2.2L; and 2005 Toyota Prius) while larger engines (Jeep Wranger Umlimited, 3.8L; Pontiac TransAm, 5.7L) had smaller improvement figures.

Improved mileage and fuel economy comes through numerous small improvements. I’d be more suspicious of anything that claimed a double digit improvement or more, unless it was clearly a radical modification. Even with the manufacturer’s limited testing, there are a range of results, and it may be that, for some vehicles, significant improvements such as this could be achieved. But I would want more wide range testing information before I invested $100 (or more) in a new set of spark plugs.

via: o2 Michigan mailing list

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