Choosing the Right Spark Plug -- It Really Does Make a Difference

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Planning to install new spark plugs in your vehicle? There are lots of choices in spark plug design these days -- plugs with one, two, three, or even four ground electrodes. There are also exotic materials like platinum, yttrium, and iridium for center and ground electrodes. So how to choose?

Bosch, one of the largest suppliers of spark plugs as original equipment for auto manufacturers as well as in the aftermarket, offers some cogent thoughts on selecting the best plug for your vehicle and how you use it.

Avoid downgrading from the original plugs

"Engine performance is built on a baseline of design technology, and that includes spark plugs. Today's engines are more sophisticated than you might imagine. Combustion chambers are contoured for optimal flow of gases, and many advanced engine designs incorporate variable valve timing. Part of the equation is a spark of very specific size, duration, and location. Downgrading will almost certainly result in reduced performance, economy, and emission control," said Reid Smith, Product Manager for Spark Plugs at Bosch.

"This is particularly true when considering the material used in the plug, and the number of electrodes the plug is equipped with. If the vehicle was originally equipped with platinum plugs, for instance, make sure you install platinum replacement plugs, if it was equipped with 4-electrode platinum plugs, install 4-electrode platinum plugs."

Take advantage of the latest technology

Engine development does not stop when vehicle production starts. Quite the contrary. Since Bosch, for instance, is a major supplier of spark plugs to domestic and import OEs, their engineers continue to work with the automakers' engine development teams to come up with designs that can work even better than that which existed when the car was first built. "So you can, and often should, upgrade from, say, single-electrode platinum spark plugs to multiple electrode platinum plugs, and maybe even to plugs with iridium or yttrium. These advanced design plugs enhanced with precious metals will provide more efficient and complete combustion, and will also last longer," Smith indicated.

Install plugs that meet your specific needs

Plugs come in a variety of designs and materials. Install one that increases performance, such as the Bosch Platinum Ir Fusion or plugs for long life such as the Platiinum+2 or Platinum+4. For motorists who prefer copper, remember that some copper plugs have been updated. Bosch's yttrium-enhanced Super Plus, for instance, lasts 50 percent longer than other copper core spark plugs, which translates into less time under the hood and more time behind the wheel. There are a lot of situations in which you can benefit from improved spark plug technology, according to Bosch. Examples include:

* Mostly short trips, which don't allow the engine and spark plugs to fully warm up and burn off deposits.

* Heavy-load use like a car-full of kids, sporting goods, or luggage.

* Operation in cold weather where start-ups can be critical.

What's your engine's condition?

If your car has 50-75,000 miles or more on the clock, it almost certainly has some internal wear, with attendant loss of some engine compression and increased oil consumption. "An engine with this kind of mileage is almost sure to develop deposits on pistons, valves and, therefore, on the spark plugs as well. As such, upgrading to a multiple electrode spark plug like Bosch's Platinum+2, Platinum+4 or Platinum Ir Fusion will provide extra ground electrodes so the spark can take the most efficient path to provide optimal spark," Smith said. These plugs utilize 'surface air gap' technology for superior spark efficiency, and are permanently preset at the factory for correct gap. And the multiple electrodes are less likely to foul.

Are you rigorous in having maintenance performed?

If you, like so many of us, are less than scrupulous about having tune-up and other services performed at the precise intervals recommended, it's probably best to upgrade to premium spark plugs. Spark plug replacement in many of today's cars is labor-intensive, and the incremental cost of premium spark plugs is relatively modest. Considering that upgraded spark plugs will deliver better fuel economy and performance for a longer time on the road than standard plugs, it's a good bet that premium spark plugs will pay for themselves long before they reach the end of their service life, according to Smith.

The bottom line?

"If you have any doubts about the way your car is used, the condition of your engine, or the likelihood of your adhering strictly to maintenance schedules, upgrade your spark plugs. It won't take long to recoup the extra parts cost, and you'll enjoy quick starts and thrifty performance for tens of thousands of miles to come," said Smith. For more information, visit www.boschautoparts.com.