HKS Super Fire Racing Spark Plug MR40XLZ

HKS Super Fire Racing Spark Plug MR40XLZ

- Type: Ruthenium Spark Plug

- Heat range: NGK #8 equivalent

- Thread length: 26.5mm

- Thread: M12

- Socket size: 16mm

- Sold individually

- Made in Japan by NGK for HKS

- HKS part no. 50003-MR40XLZ

Compatible with a wide range of vehicles, for full compatibility with your engine, please refer to the HKS Super Fire Racing Spark Plug Application Chart.

The HKS Super Fire Racing MR Series spark plug is designed for modern high-performance and lightly tuned turbo engines requiring an M12 long reach plug with protruding electrode. This plug delivers stable ignition under increased boost and higher combustion temperatures.

Featuring a 0.6mm ruthenium alloy center electrode (reduced from the typical 0.8mm), voltage requirement is lowered while ignition performance is significantly improved. The platinum-tipped ground electrode, reinforced with a copper core, enhances durability, combustion quality, and resistance to temperature rise. The shortened and optimized outer electrode design increases vibration resistance and long-term reliability.

The MR Series adopts a shell projecting type design to improve pre-ignition resistance and structural strength compared to traditional bracket projecting styles. With ignition point protrusion increased for improved combustion efficiency, it promotes quicker throttle response, smoother idle, improved cold starts, and cleaner fuel burn.

Suitable for stock replacement (NGK heat range 8 equivalent) as well as tuned applications seeking improved durability and peace of mind under higher output conditions.

For more information visit https://www.hks-power.co.jp/en

HKS Super Fire Racing MR Series Chart