HKS 50003-M45I Super Fire Racing M-Series Iridium Spark Plug ISO Type HR 45

Vehicle Fitment

• Universal Fit - Multiple Applications (ISO Type, 14mm Thread)

Fitment Notes

• Universal part - no vehicle-specific fitment assignment applies
• Verify thread size (14x19mm) and heat range (HKS #45 / NGK equivalent #9) match your application before installation
• Sold individually (1x per listing) - order quantity based on cylinder count

Features

• 0.6mm iridium alloy center electrode reduces required voltage and improves ignition reliability
• Square platinum chip on outer electrode enhances durability and sustained ignition performance
• Short-type outer electrode with tapered shape minimizes interference and optimizes spark gap exposure
• Anti-vibration thermal edge design prevents electrode tip breakage under high-load conditions
• Nickel-plated housing resists corrosion and prevents premature housing deterioration
• High melting point iridium alloy (2,454°C) withstands extreme compression and minor detonation
• Anti-carbon buildup design keeps electrodes clean under sustained high-RPM or boosted operation
• Compatible with both stock and tuned engine builds requiring a colder heat range

Specifications

• Part Number: 50003-M45I
• Series: Super Fire Racing M-Series
• Type: ISO Type
• Center Electrode: 0.6mm Iridium Alloy
• Outer Electrode: Platinum Chip
• Thread Size: 14mm x 19mm
• Wrench Size: 16mm
• Heat Range (HKS): 45
• Heat Range Equivalent (NGK): #9
• Heat Range Equivalent (Denso): 27

Included Components

• 1x HKS Super Fire Racing M45I Spark Plug

Product Description

The HKS Super Fire Racing M45I is a high-performance iridium spark plug built for engines that demand more than a standard OEM plug can deliver. With a 0.6mm iridium alloy center electrode and a square platinum-tipped outer electrode, the M45I provides reliable ignition, reduced misfires, and improved throttle response - whether the engine is naturally aspirated or running forced induction. The colder HKS heat range of 45 (equivalent to NGK #9) makes it well-suited for modified or high-compression applications where heat dissipation is critical.

Designed to resist carbon fouling and electrode wear, the M45I features a shortened outer electrode with a tapered anti-vibration profile that keeps the plug stable under aggressive driving. The nickel-coated housing adds an extra layer of protection against rust and galvanic corrosion. Each plug is sold individually, so buyers should order the correct quantity to match their engine's cylinder count. Always confirm thread size (14x19mm) and heat range compatibility before installation.