Maximize your engine's combustion efficiency with the HKS M40 Super Fire Racing Spark Plug. This JIS-type performance plug is a staple for high-output JDM engines, offering an NGK Heat Range 8 equivalent to ensure stability and prevent pre-ignition in tuned or high-boost applications.
Designed as the ultimate "all-rounder" for both street and circuit use, the M-Series focus is on reliability, durability, and anti-carbon buildup.
0.6mm Iridium Alloy Center Electrode: Drastically reduces the voltage required for a spark, resulting in improved ignition performance and a more responsive throttle.
Platinum Ground Electrode: Features a square platinum chip that enhances durability and provides a consistent spark gap even under extreme cylinder pressures.
Short-Type Anti-Vibration Electrode: Specifically engineered to resist the high-frequency vibrations found in high-RPM racing engines, preventing electrode fatigue and failure.
Thermal Edge Technology: The ceramic insulator features a "Thermal Edge" that discharges to help burn off carbon deposits, keeping the plug clean during extended idling or stop-start driving.
Superior Heat Management: The copper core and nickel-plated housing provide excellent heat dissipation and corrosion resistance.
HKS SKU: 50003-M40
Plug Type: JIS Type
Heat Range: NGK #8 Equivalent
Thread Size: $14\\text{mm} \\times 19.0\\text{mm}$
Wrench Size: $16\\text{mm}$
Electrode: Iridium Center / Platinum Ground
The HKS M40 is a popular choice for a variety of performance engines requiring a JIS-spec plug, including:
Nissan: Silvia (S13/S14/S15), Skyline (ER34/R33/R32), Stagea (WC34)
Toyota: Supra (JZA80), Chaser (JZX100), Aristo (JZS161) — Fits many 1JZ/2JZ-GTE VVTi variants.
Mitsubishi: Lancer Evolution (EVO IV through IX)
Subaru: Early Impreza WRX & STI models
Purchasing Note: Spark plugs are sold individually in Australia. For a 4-cylinder engine (Silvia/EVO), please order 4. For a 6-cylinder engine (Skyline/Supra), please order 6.
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