HKS 50003-MR45XLB Super Fire Racing Spark Plug #9 - Subaru WRX STI EJ25 - Lancer Evo 7-8-9 / Nissan SR20DET - 1 Piece

HKS 50003-MR45XLB Super Fire Racing Spark Plug #9 – Subaru WRX STI EJ25 / Lancer Evo 7‑8‑9 / Nissan SR20DET

The HKS MR45XLB is an iridium‑tipped racing plug developed for modified turbo engines with high heat and pressure resistance. With a #9 heat range, it provides secure combustion, strong spark and detonation resistance, especially in engines running high boost and aggressive ignition timing.

✅ #9 heat range: ideal for high boost and tuned applications

✅ “XLB” type: extended and protruding tip for improved flame spread

✅ Fine iridium electrode: stable spark even at low voltage

✅ Rapid combustion characteristic reduces turbo lag

✅ Less misfire and cleaner burn at high RPM

Offering much higher temperature tolerance than OEM plugs, the MR45XLB helps control combustion chamber temperatures in high‑boost turbo engines, preventing piston and gasket damage. Highly recommended for track and racing use.

Compatible Engines and Vehicles

- Subaru WRX STI EJ25 (2006–2021)

- Mitsubishi Lancer Evolution 7 / 8 / 9 (4G63T)

- Nissan Silvia / 180SX / Pulsar GTI‑R (SR20DET)

Installation

Same dimensions as the OEM plug and can be swapped directly. Use a torque wrench and tighten to the manufacturer’s specifications. Check your ignition system for compatibility with the heat range.

Note

A #9 plug is recommended only for high‑performance and tuned applications; it may be too cold for stock engines. Consider your engine build before ordering.