Spark Plug - HKS M40i - Grade 8

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  • translation missing: en.product.regular_price £19.20 (Ex-vat : £16.00)

Stock status: 12 In stock



HKS Mi-Series Super Fire Racing Spark Plug - M40i Grade 8

HKS Mi-Series Super Fire Racing spark plugs are high performance Iridium plugs designed to handle advanced levels of tuning and provide Improved ignition performance, durability and anti-carbon build-up.

HKS Mi Series Spark Plug Features:

  • 0.6mm Iridium Alloy Centre Electrode. Iridium Alloy Centre 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 centre 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.
  • Heat Range: 8


Fensport Tip: How to choose a sparkplug grade. (Guide Only)

For NA Cars:

Usually use a grade 6 for most road applications, a grade 7 can be used in hi compression race type cars, grade 8 in extreme rev/compression cars.

For Turbo Cars:

Grade 6 is usually for standard cars, Grade 7 mild upgrades usually 1.2 bar boost, Grade 8 above 1.2bar, Grade 9 above 1.6

Nitrous Oxide:

Usually a colder grade plug is often used when using nitrous oxide.

If you need help please call for details


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- Price is for 1 single spark plug