Denso Iridium Spark Plugs (Set/4), 2004-2017 STi & 2006-2014 WRX

Denso Iridium Spark Plugs (Set/4), 2004-2017 STi & 2006-2014 WRX



Temperature Range:

Product Description

  • 2006-2007 WRX
  • 2008-2014 WRX
  • 2004-2007 STi
  • 2008-2014 STi
  • 2015-2017 STi
  • 2004-2008 Forester XT
  • 2005-2009 Legacy GT

  • Brand: Denso
  • Manufacturer's Part Number: IKH22
  • Primary Material: Iridium
  • Pack Quantity: 4
  • UPC: 042511534544
  • Condition: New Product

Manufacturer's Description:
Iridium Power Technology -
Fifty million years ago, an asteroid composed almost entirely of the precious metal Iridium (Ir-77) struck the earth creating the Gulf of Mexico. From this catastrophe came a metal with properties ideal for spark plug construction. Using this element, DENSO has evolved spark plug design to a new level.

The U-Groove Design -
In 1972, we received a patent for the popular U-Groove ground electrode design. This electrode was developed to meet the demand for improved ignitability, which is necessary for an increase of efficiency in emission gas purification and fuel consumption. The U-Groove gives the flame a groove to grow in, thereby creating a larger flame front for a more complete combustion even in the case of lean air-fuel mixture. A conventional, flat ground electrode design of regular plugs crushes the flame preventing full spark potential.

Iridium Alloy -
In a never-ending effort to improve upon success, DENSO developed an Iridium alloy that is superior to platinum based on hardness, strength and melting point. The new Iridium alloy is composed primarily of Iridium with rhodium mixed in for oxidation wear. Iridium Alloy Pure Iridium has a melting point of almost 700°C higher than platinum, and had the greatest potential for resistances against wear. Iridium by itself is susceptible to oxidation wear at temperatures over 900°C, however, ordinary driving around town an engine would never reach these temperatures. Further testing proved that Iridium alone would not meet DENSO's demanding standards. After testing other pure metals combined with Iridium, rhodium proved to be the best choice to meet the needs of DENSO's spark plug engineers.

Laser Welding Process -
360 Laser Welding Process DENSO's Iridium Alloy had all of the qualities to produce the world's best spark plug, but conventional tooling prevented DENSO from mass manufacturing. Due to the high melting point there wasn't a welding process hot enough to join the Iridium tip to the nickel base. Necessity to melt the Iridium to the nickel base forced DENSO to pioneer its third patent, the 360° Laser Welding Process, to provide a seal so reliable; the electrode resists wear even in the worst combustion conditions.

Inventory Updated Daily

Customer Ratings & Reviews

Be the first to rate this item!

Write Review