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Old 03-15-2017, 10:47 AM   #317
His Dudeness, El Duderino
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Join Date: Dec 2009
Location: Torrance, CA

Unlike conventional ignition systems, waste spark DIS ignition systems use half the spark to fire the opposite spark plug unconventionally from the side electrode to the center electrode. Copper core standard plugs and copper core single platinum spark plugs are not designed to withstand this reverse polarity firing and will suffer premature gap growth due to center electrode erosion.
There's nothing special about "how" the wasted spark system fires the plug. They fire normally, but twice as often. Not sure how the author of the article above came up with the mumbo-jumbo about "reverse polarity firing" but yeah...that's not true.

Gap growth will stress ignition system components by requiring more voltage to fire, eventually leading to misfire, loss of performance and fuel economy. This degradation can be noticeable as soon as 20,000 miles after the plug is installed.
This part is true, and perhaps what this refers to is plugs wearing out more quickly in a wasted spark application due to being fired once per engine revolution, or twice as many times as a plug in a non-wasted (sequential) ignition firing order.
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