HKS Spark Plug for GTR 350Z 370Z FA20 #8 (50003-M40HL)




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HKS M-Series Super Fire Racing spark plugs are sold individually. These high performance iridium plugs are designed to handle higher boost with improved ignition performance and anti-carbon build-up. Fits Nissan R35 GTR, 350Z, 370Z and FA20 Subaru WRX, BRZ, FRS and Toyota GT86.

Vehicle Fitment:
Nissan R35 GT-R
Nissan 350Z
Nissan 370Z
Subaru BRZ
Scion FR-S
Toyota GT86
Subaru WRX FA20 2015+
(and more!)

(1) Spark Plug
Spark plugs are sold individually price is for one plug!

Heat Range and Thread

Part Number: Heat Range: Thread:
50003-M40HL NGK #8 12mm x 26.5

HKS Plug Heat Range Conversion Chart

HKS 25 30 35 40 45 50 52.5 55
DENSO 16 20 22 24 27 31 32 34
NGK 5 6 7 8 9 10 10.5 11

0.6mm Iridium Alloy Center Electrode:
Iridium Alloy Center Electrode reduces voltage requirement as well as improving ignition performance and durability.

Outer Electrode with Platinum Chip:
The Outer Electrode incorporates a square platinum chip which improves durability, and when combined with the iridium center electrode boosts ignition performance.

Short Type Outer Electrode (Anti-Vibration):
The outer electrode has been shortened and engineered with the ideal shape to decrease weight for resistance against vibration. This anti-vibration design improves 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:
Discharges will occur in the Spark Support Gap (space between the tip of insulator and the base of the outer electrode) to help prevent carbon buildup.

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°C, opposed to the 1769°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

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