HKS 50003-M40XL Iridium Spark Plugs
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HKS S-Series Super Fire Racing Spark
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.