HKS 50003-M45IL Super Fire Racing M-Series Iridium Spark Plug Long Reach HR 45

Vehicle Fitment

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

Fitment Notes

• Universal part - no vehicle-specific fitment assignment applies
• "L" suffix denotes Long Reach thread design - confirm thread reach compatibility before ordering
• Verify heat range (HKS #45 / NGK equivalent #9) suits your engine tune and compression level
• Sold individually (1x per listing) - order quantity to match your engine's cylinder count

Features

• Long Reach thread design suits engines requiring extended thread engagement depth
• 0.6mm iridium alloy center electrode lowers voltage demand and sharpens ignition performance
• Square platinum chip on outer electrode delivers sustained durability under high combustion loads
• Short-type anti-vibration outer electrode resists tip breakage during aggressive or circuit driving
• Thermal edge design and spark support gap actively reduce carbon fouling on electrode surfaces
• Nickel-coated housing protects against corrosion and extends plug service life
• Engineered for both stock and tuned engines requiring a colder-than-OEM heat range
• Performs reliably under lean mixtures, high boost pressure, and sustained high-RPM conditions

Specifications

• Part Number: 50003-M45IL
• Series: Super Fire Racing M-Series
• Type: ISO Type - Long Reach
• Center Electrode: 0.6mm Iridium Alloy
• Outer Electrode: Square Platinum Chip
• Thread Size: 14mm x 19mm (Long Reach)
• Wrench Size: 16mm
• Heat Range (HKS): 45
• Heat Range Equivalent (NGK): #9
• Heat Range Equivalent (Denso): 27

Included Components

• 1x HKS Super Fire Racing M45IL Spark Plug

Product Description

The HKS Super Fire Racing M45IL is the Long Reach variant of HKS's flagship M-Series iridium spark plug, engineered for engines that require deeper thread engagement than a standard-reach plug provides. It shares the same core construction as the M45I - a 0.6mm iridium alloy center electrode paired with a square platinum-tipped outer electrode - delivering stronger ignition, reduced misfires, and improved combustion efficiency across a wide range of engine builds. The HKS heat range of 45 (NGK #9 equivalent) positions this plug firmly in the performance-tuning segment, making it a strong choice for boosted or high-compression applications.

The M45IL's anti-vibration short outer electrode and thermal edge design work together to minimize carbon deposits and resist electrode wear during sustained high-load use. Buyers should confirm that their engine requires the Long Reach thread format before ordering, as this plug is not interchangeable with standard-reach applications. Sold individually - order the correct quantity for your cylinder count.