HKS SUPER FIRE RACING M40LF - Black Ops Auto Works
HKS SUPER FIRE RACING M40LF - Black Ops Auto Works
Click to zoom in

HKS SUPER FIRE RACING M40LF

HKS
HKS50003-M40LF
4957266720417
Spark Plugs
3 Units In Stock - Ships Next Business Day
$ 300.00
FREE Ground Shipping!
$ 300.00

SKU: 50003-M40LF | UPC: 4957266720417

HKS SUPER FIRE RACING M40LF Spark Plug 2002-2021 Subaru Impreza WRX STI

The HKS Super Fire Racing M40LF delivers reliable ignition for 2002-2021 Subaru Impreza WRX and STI models. This iridium plug ignites fuel mixtures more effectively in turbocharged EJ20 and EJ25 engines for increased horsepower and throttle response. Built for racing it withstands high boost and RPM demands.

Key Features

  • 0.4mm Iridium Center Electrode: Creates focused spark for complete combustion at high engine speeds
  • Platinum Flat Pad Ground Electrode: Reduces electrode wear extends plug life under racing conditions
  • Heat Range 40: Handles extreme heat from turbo setups prevents pre-ignition
  • High-Strength Ceramic Insulator: Resists flashover ensures consistent performance in wet or dirty environments
  • Nickel-Plated Shell: Thread M14x1.25 reach 26.5mm hex 16mm promotes heat dissipation fights corrosion

Product Notes

  • Sold as single plug full set of 4 required for WRX 6 for STI
  • Factory gap 0.8mm adjust to 0.75-0.85mm based on engine tune
  • Packaged in protective plastic case for safe handling

Installation Notes

  • Professional installation recommended.
  • Torque to 18-21 ft-lbs using anti-seize on threads
  • Direct OEM replacement works with factory ignition coils

This Part Fits

Year Make Model Submodel
2002-2007 Subaru Impreza WRX
2004-2007 Subaru Impreza WRX STI
2008-2014 Subaru Impreza WRX
2008-2021 Subaru Impreza WRX STI
2004-2009 Subaru Impreza WRX TR

Why Choose HKS?

  • 45 years leading JDM performance parts for Subaru enthusiasts
  • Japanese manufacturing delivers exact tolerances for EJ engines
  • Tested in Super GT and rally for real-world track results

Frequently Asked Questions

  • Q: Will this plug fit my 2010 STI hatchback?
    A: Yes it matches all 2002-2021 Impreza WRX STI sedan hatch wagon with EJ25 turbo engines
  • Q: What electrode materials improve longevity?
    A: 0.4mm pure iridium center and platinum ground pads resist spark erosion last 2x longer than copper
  • Q: Does HKS provide warranty support?
    A: Limited manufacturer defect warranty contact retailer for claims with proof of purchase

Shipping & Handling

  • Method: UPS Ground or USPS Priority
  • Availability: In stock - ships same or next business day
  • Packaging: Individual plastic case in 4 x 1 x 1 inch box
  • Weight: 1.6 oz shipping weight

Request For Information

Have questions about HKS SUPER FIRE RACING M40LF? Fill out the form below and we'll get back to you by the next business day.
Engine

Engine

Engine parts and engine bay upgrades for Dodge, Jeep, RAM, Chrysler, Chevrolet, Ford, Toyota, Nissan, Subaru, and Honda vehicles are stocked at Black Ops Auto Works. Shop oil catch cans, supercharger pulleys, thermostats, radiators, cooling parts, throttle bodies, intake manifolds, headers, ignition coils, spark plugs, sensors, gaskets, fuel pumps, valve covers, engine covers, billet cap covers, and full engine bay dress-up parts for HEMI, Hellcat, Trackhawk, Redeye, Demon, Scat Pack, RAM TRX, LS, LT, Coyote, EcoBoost, K-Series, and 2JZ builds. Every product is filterable by year, make, model, trim, engine, and drivetrain so the correct part ships the first time. Black Ops Auto Works carries 14,298 engine SKUs across performance, cooling, oil control, ignition, and appearance categories. What This Category Covers The Engine collection combines OEM-replacement engine service parts with performance aftermarket upgrades for supercharged, turbocharged, and naturally aspirated builds...

View Engine Products
HKS

HKS

HKS Japanese performance parts for Toyota Supra, Nissan Skyline GT-R, Nissan Silvia and 240SX, Subaru WRX and STI, and other JDM platforms are stocked at Black Ops Auto Works. Shop turbo kits, cat back exhaust systems, coilovers, blow off valves, and engine management upgrades for RB26DETT, SR20DET, 2JZ-GTE, and EJ series turbocharged engines. Every product is filterable by year, make, model, trim, engine, and drivetrain so the correct part ships the first time. Black Ops Auto Works carries 607 HKS SKUs across forced induction, exhaust, suspension, and engine management categories. What This Collection Covers HKS has built its reputation on Japanese sport compact and sports car performance since the late 1970s, developing turbo kits, exhaust systems, and suspension for platforms including the Toyota Supra 2JZ-GTE, Nissan Skyline GT-R RB26DETT, Nissan Silvia and 240SX SR20DET, and Subaru WRX and STI EJ and FA series engines. This collection brings together fitment verified HKS pa...

View HKS Products
Ignition

Ignition

Ignition parts keep every cylinder firing on time and every start crisp, and Black Ops Auto Works stocks the full system in one collection. Spark plugs, coil packs, plug wires, distributors, starters, sensors, and glow plugs from NGK, Granatelli, MSD, Ford Performance, Moroso, Mishimoto, HKS, and COBB all live here. Whether you are chasing a weak spark on a daily driver, refreshing a tune-up on an LS or Coyote build, or wiring in a full coil-on-plug conversion, this collection has the OEM-grade replacements and the performance upgrades to keep the mixture lighting off cleanly under boost, high RPM, or heavy load. What Belongs in the Ignition System The ignition system is more than just the spark plug. Every part in this collection plays a role in taking 12-volt battery power, stepping it up to tens of thousands of volts, and delivering that spark to the right cylinder at the right instant. Weakness anywhere in the chain shows up as misfires, hard starts, poor mileage, or a chec...

View Ignition Products
Spark Plugs

Spark Plugs

Spark plugs for cars, trucks, SUVs, and import platforms are stocked at Black Ops Auto Works. Shop iridium spark plugs, laser iridium spark plugs, double platinum spark plugs, nickel spark plugs, and racing spark plugs for LS, LT, HEMI, EcoBoost, Subaru EJ and FA, and import turbo engines. Every product is filterable by heat range, thread size, gap, and vehicle year, make, model, and engine so the correct spark plug ships the first time. Black Ops Auto Works carries 480 spark plug SKUs across every major electrode material and heat range. What This Category Covers Spark plugs ignite the compressed air and fuel mixture in each cylinder, and the correct plug for your engine depends on electrode material, heat range, and thread specification. Choosing the wrong heat range or gap can cause misfires, fouling, or in extreme cases pre-ignition damage. Electrode Materials Iridium and laser iridium plugs use a fine center electrode for a stronger, more consistent spark and the longest se...

View Spark Plugs Products
Military & First Responder Discounts

Military & First Responder Discount Program

Black Ops Auto Works proudly honors active duty military, veterans, National Guard, reserves, police officers, firefighters, and EMTs with an exclusive 5% discount on all performance parts and carbon fiber upgrades. Verify instantly and start saving today.

Learn More & Apply

Your cart

×