NGK ZFR5BIX 93274 Spark Plug Iridium IX

The NGK ZFR5BIX 93274 is a 14 mm diameter Iridium IX spark plug, described as an upgrade from a standard plug. Its 0.6 mm fine-wire iridium centre electrode needs less voltage to fire and produces a more concentrated spark, giving quicker starting, crisper throttle response and steadier idle, particularly on high-compression, tuned or high-revving engines.

Iridium is around six times harder than platinum and wears very slowly, so the gap stays accurate far longer than with nickel. The tapered ground electrode reduces quenching of the flame kernel. It replaces the equivalent standard NGK plug of the same heat range; check the gap before installation.