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Spark Plug Wires

By: Ray Frescas03/21/2012 < Back to Blog Home
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The spark plug wires are the arteries of the ignition system. They provide the all-important path that allows the spark to transfer from the distributor cap to the spark plugs. The importance of good quality spark plug wires cannot be stressed enough! Plug wires live in a nasty environment and deal with high heat, abrasion, and getting whipped around at high speeds. They also need to be able to deliver high levels of voltage, while suppressing electromagnetic interference (EMI), which is created when high voltage passes through a wire.


EMI refers to electrical noise or interference. Not only can it be an annoying buzz through the radio, but it can also wreak havoc on other electronics such as the rev limiter, or even the ECU of a car equipped with an EFI system. Original equipment spark plug wires combat EMI by using a carbon core material that has a very high resistance to the flow of the spark energy. The aftermarket offers a variety of wire sets that offer much lower resistance to ensure the most spark possible reaches the plugs.


When you’re shopping for wires, look for lower resistance (measured in ohms), but also look for good EMI suppression. Another area of importance in the spark plug wire is the crimp between the terminal and the wire. Poor crimps can contribute to intermittent performance, a dead cylinder, and other problems. Also pay attention to the spark plug wire boots, as they need to survive parked in close proximity to the exhaust manifolds where heat is at its most extreme.


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