HKS Super Fire Racing MR40XLZ Spark Plug (Ruthenium)

HKS Super Fire Racing MR Series Spark Plugs Specifications

Designed for both tuned and stock engines, the HKS Super Fire Racing MR-series ruthenium spark plugs offer superior ignition performance, excellent durability and increased resistance to fouling.

In addition to a longer service life (around 25% longer than iridium alloys), the use of ruthenium alloy improves fuel combustion, resulting in quicker throttle response, smoother idling and better cold starts.

Thanks to a reduced ignition voltage, these spark plugs deliver a more powerful spark, even under demanding conditions such as a lean fuel mixture or high boost pressure.

The design of these spark plugs and their next-generation materials improve their resistance to the high thermal and mechanical stresses encountered during intensive track use or in highly tuned engines.

Thermal Edge technology also limit carbon deposits, ensuring reliable and consistent ignition across a wide range of combustion conditions.

Warning: using these spark plugs in a vehicle that is not compatible with this type of spark plug may cause serious damage to the engine.

Please note: these spark plugs are sold individually; please adjust the quantity in your basket as required.

Application examples:

• BMW M2 F87 incl. Competition - N55B30A, S55B30A
• BMW M3 E90 - S55B30A
• BMW M3 Competition F80 - S55B30A
• BMW M4 F82 incl. Competition - S55B30A
• BMW M5 F10 - S63B44B
• BMW M6 F06 - S63B44B
• Suzuki Swift Sport ZC33S - K14C

Check the official HKS catalogue to find the right spark plug for your vehicle and its specifications.

Heat Range Conversion Chart