
Ultra-fine wire NGK iridium, 0.7mm

Fine wire NGK platinum, 1.1mm

Traditional center electrode, 2.5mm
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Spark plugs with fine wire center electrodes operate better for two reasons. First, a smaller center electrode requires less voltage to jump the gap. This means fewer misfires, which will be seen in higher mileage and more horsepower. The second reason is smaller center electrodes reduce quenching. The smaller center electrodes have required exotic metals such as platinum or iridium so that they can still maintain (and sometimes surpass) the longevity of a traditional spark plug. NGK makes both platinum fine wire (1.1mm diameter center electrode) plugs and Iridium ultra-fine wire (0.7mm diameter center electrode), a traditional center electrode is typically 2.0 to 2.5mm. |