HKS 5408-S40i Iridium Spark Plugs

ALL PLUGS SOLD INDIVIDUALLY

HKS S-Series Super Fire Racing Spark Plugs

HKS S-Series Super Fire Racing Spark Plugs are high performance Iridium plugs designed to handle advanced levels of tuning and still offer easy start-up and smooth idling.

• 0.4mm diameter Iridium plug electrode core
• U-shaped grooved electrode
• S-Series Super Fire Spark Plugs are recommended for smooth cold starting, response and acceleration.

M-Series Super Fire Spark Plugs

HKS M-Series spark plugs are high performance Iridium plugs designed to provide improved ignition performance, durability and anti-carbon build-up.

• 0.6mm Iridium Alloy Center Electrode
• Outer Electrode with Platinum Chip
• Short Type Outer Electrode (Anti-Vibration)
• Thermal Edge
• Spark Support Gap

*M Series is recommended for reliable ignition, durability and anti-carbon buildup under high load.

The Iridium alloy is used because of its durability and reliability. On an average plug, a narrow core typically shortens life span of plug but with the intense durability of iridium there is no sacrifice in any longevity. With a high melting point of 2454 degrees C, opposed to the 1769 degrees C of white gold, the electrode can tolerate the high levels of compression and minor knocking without any deterioration. A nickel coating on the housing also prevents the spark plug from premature deterioration. The Iridium plugs are available for multiple applications and offered in colder heat ranges of 7 and up and specifically for rotary, heat ranges of 9 and up are offered.