The heart of your performance vehicles power lies in a perfect spark. For those who custom tune their cars for maximum performance, a reliable spark plug is essential. The HKS M40 Super Fire Racing Spark Plugs are engineered to keep your engine firing robustly. Featuring an iridium alloy center electrode, these plugs reduce voltage requirements while boosting ignition performance and durability. The outer electrode, equipped with a platinum chip, enhances ignition performance and is shaped for anti-vibration, ensuring longer life. The ceramic insulator's thermal edge minimizes carbon deposits from long idling. These plugs are better firestarters than Prodigy. During your next tune, experience the difference high-performance spark plugs can make. Our gearhead staff is ready to help you determine if these plugs are the right fit for your engine.

• 0.6mm Iridium Alloy Center Electrode
• Iridium Alloy Center Electrode reduces voltage requirements as well as improves ignition performance and durability.
• Outer Electrode with Platinum Chip
• The Outer Electrode incorporates a square platinum chip, which improves durability and boosts ignition performance when combined with the iridium center electrode.
• Short Type Outer Electrode (Anti-Vibration)
• Discharges will occur in the Spark Support Gap (space between the tip of the insulator and the base of the outer electrode) to help prevent carbon buildup.

Benefits

• The outer electrode has been shortened and engineered with the ideal shape to decrease weight for resistance against vibration. This anti-vibration design improves the longevity of the outer electrode.
• Thermal Edge
• After long idling or various combustion conditions, carbon buildup can occur causing misfires. The Thermal Edge of the ceramic insulator will discharge to help decrease carbon deposits.
• Spark Support Gap
• M Series is recommended for reliable ignition, durability, and anti-carbon buildup under high load.