HKS 50003-MR45XLZ Super Fire Racing M12 Spark Plug Ruthenium Heat 9

Vehicle Fitment

• Universal - fits engines using M12 long-reach, protruding-electrode spark plugs
• Commonly used on turbocharged direct-injection engines, including Honda Civic Type R (FK8) and Suzuki Swift Sport (ZC33S)

Fitment Notes

• Not vehicle-specific; compare plug shape and dimensions against your factory plug before installing, as fitment varies by engine

Features

• Ruthenium alloy center electrode for improved durability and reliability
• Fine-wire design supports a stronger, more consistent spark
• Protruding electrode tip suited to direct-injection turbo engines
• NGK-equivalent heat range 9 for light-to-moderate tuning and increased boost
• Built on HKS's proven Super Fire Racing M-series platform

Specifications

• Thread size: M12
• Thread length: 26.5mm
• Hex size: 16mm across flats
• Heat rating: 45 (NGK equivalent heat range 9)
• Electrode material: Ruthenium alloy

Included Components

• 1x Spark plug (sold individually)

Product Description

The HKS 50003-MR45XLZ is a Super Fire Racing MR-series spark plug built for M12 long-reach applications with a protruding electrode tip, a configuration commonly found on modern turbocharged direct-injection engines. Its ruthenium alloy center electrode is designed to hold up under the increased heat and cylinder pressure that come with light tuning or elevated boost.

With an NGK-equivalent heat range of 9, it's suited to drivers pushing past stock output without moving into a fully race-only heat range. Since it's sold as a universal-fit plug rather than tied to one vehicle, buyers should confirm thread size, reach, and electrode shape against their engine's stock plug before ordering.