Iridium is a precious metal that is 6 times harder and 8 times stronger than platinum, it has a 1,200°(F) higher melting point than platinum and conducts electricity better. This makes it possible to create the finest wire center electrode ever. Prior till now, NGK has favored platinum for their long life or performance spark plugs due to its high melting point. However platinum alone is no longer enough, ultra long life spark plugs and smaller center electrodes required harder and stronger precious metals. The strength, hardness and high melting point of iridium makes it very well suited for a fine wire plug and for ultra long life spark plugs. Though better, iridium's not perfect, it is very expensive, and at higher temperatures it oxides, thus rendering pure iridium as an expensively poor choice for spark plug construction. However when blended with other precious metals such as Yttria, Rhodium or Platinum, you can enhance those metals advantages with the superior strength and hardness of Iridium. DO NOT BE FOOLED, all iridium plugs are not the same. Iridium content varies, some other brands of iridium plugs are priced lower, (usually due to lower iridium content). They likely will not perform or last as long as a genuine NGK iridium spark plug.
Iridium IX Plug, 14mm Thread Size, 26.5mm (1.04") Reach, 5/8" (16mm) Hex Size, Gasket Seat, Resistor, Solid Terminal Nut, Projected Tip, Fine Wire (0.6mm) Iridium Center Electrode, Tapered Cut Ground Electrode, .031" (0.8mm) Gap, Heat Range 7
Fitment: Confirm before placing your order.
Year Make Model Sub Model
2004 - 2012 SUBARU IMP,LGT, FXT WRX, STi, LGT, FXT
Cylinders Liters Fuel Type Fuel Delivery Aspiration Engine Designation
H4 2.5 GAS FI T EJ257, EJ255
Notes
Gap: 0.31
