HKS SUPER FIRE RACING M40LF - Black Ops Auto Works
HKS SUPER FIRE RACING M40LF - Black Ops Auto Works
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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
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