Your engine needs at least one spark plug per cylinder to ignite the fuel and air mixture and make the engine run. But not all spark plugs are the same. There are several different types on the market, and you’ll need to ensure that you’re getting the right type. Additionally, your vehicle might have more than one spark plug per cylinder (some high-performance engines have two).
Types of spark plugs
Performance: One of the first types of spark plugs you’ll find is performance – these come in a range of different styles, although the only thing that really varies is the shape, configuration and placement of the metal tab at the bottom. This is what the electrode arcs to. You’ll find single tab, dual tab, and quad tab configurations available, all claiming to offer better performance than the others. However, there is conflicting evidence about whether these types of plugs actually offer much of a benefit over the single tab design.
Heat Rating: Another consideration when buying spark plugs is the heat rating from the manufacturer. Basically, this is a notation on how quickly heat dissipates from the spark plug tip after arcing. If you’re after better performance, you'll want a higher heat rating. For normal driving, it’s not so much of a concern.
Electrode Material: You’ve doubtless seen a number of different electrode materials on the market. They range from copper to iridium and platinum (and double platinum, for that matter). The different materials have no effect on performance. They’re designed to make the plugs last longer. Copper wears out the fastest, but offers the best conductivity. Platinum can last for a long time, as can iridium, but neither offers better performance than basic spark plugs without the high cost for the exotic metals.
The best type of spark plug for your vehicle is most likely the same kind that came from the manufacturer. If you’re not sure what those are, check your owner’s manual or talk with a trusted mechanic. However, if you’re modifying your engine for better performance, you probably want to look for a high performance spark plug that will offer better combustion.