NGK LKAR7ARX-11P (94493) Premium RX Spark Plug

Unlike standard Iridium plugs, the NGK RX series uses a Ruthenium alloy that has a much higher resistance to oxidation and chemical wear. This “High Ignitability” technology ensures the electrode tip remains sharp and efficient for over 100,000 miles, providing more consistent combustion cycles even as the plug ages compared to traditional precious metal alternatives.

Modern high‑pressure environments—like those found in Turbocharged or Gasoline Direct Injection (GDI) engines—can cause “spark blowout” or electrode erosion in softer metals. Ruthenium is structurally tougher than Iridium, allowing it to withstand extreme cylinder pressures and heat without degrading, resulting in smoother idling and better throttle response under heavy load.

Yes. NGK RX plugs are backward compatible. Even if your vehicle originally came with Platinum or Iridium IX plugs, upgrading to Ruthenium provides immediate benefits such as improved fuel economy, more reliable cold starts, and reduced emissions due to a more complete and efficient burn of the air‑fuel mixture.

NGK RX plugs come pre‑gapped for specific applications and should generally not be adjusted, as the fine‑wire tips are delicate and easily damaged by standard gapping tools. Additionally, NGK uses a specialized trivalent plating on the threads; this provides its own lubrication and corrosion protection, so the use of anti‑seize is not recommended as it can lead to over‑torquing.