SKU: 50003-M40I | UPC: 4957266720240
HKS SUPER FIRE RACING M40i for Nissan Skyline R33-R34 RB25DET Toyota JZX100 1JZ-GTE Subaru WRX
HKS Super Fire Racing M40i is a high-performance iridium spark plug for turbocharged JDM engines. It fits Nissan Skyline R33-R34 RB25DET, Toyota Mark II Chaser Cresta JZX100 1JZ-GTE, Subaru Impreza WRX GC8 EJ20 and more. This plug provides focused spark energy for quicker combustion, sharper throttle response, and added power in high-rev setups.
Key Features
- 0.4mm Iridium Center Electrode: Pinpoint spark concentration ignites lean mixtures reliably at redline speeds
- Platinum Ground Electrode with Taper Cut: Accelerates flame growth while minimizing quenching for fuller combustion chamber fill
- M40i Heat Range: Resists fouling in boosted applications with elevated cylinder temps and pressures
- OEM Dimensions: 14mm thread, 26.5mm reach, 16mm hex for drop-in replacement without clearance issues
- Racing Durability: Outlasts nickel plugs under extreme track conditions with consistent output
Product Notes
- For modified or racing engines. stock use possible but performance shines in tuned setups
- Factory gapped to 0.8-0.9mm. verify with feeler gauge before install
- Single plug packaging. order sets of 6 for inline-6 or 4 for inline-4 engines
Installation Notes
- Professional installation recommended.
- Torque to 20-25 Nm (15-18 ft-lbs) using anti-seize on threads
- Works with OEM ignition coils and plug wires
This Part Fits
| Year | Make | Model | Submodel |
|---|---|---|---|
| 1993-1998 | Nissan | Skyline | R33 RB25DET |
| 1998-2002 | Nissan | Skyline | R34 RB25DET |
| 1999-2002 | Nissan | Silvia | S15 SR20DET |
| 1996-2000 | Toyota | Mark II | JZX100 1JZ-GTE |
| 1996-2000 | Toyota | Chaser | JZX100 1JZ-GTE |
| 1996-2000 | Toyota | Cresta | JZX100 1JZ-GTE |
| 1991-2000 | Toyota | Aristo | 2JZ-GTE |
| 1996-2000 | Subaru | Impreza WRX | GC8 EJ20 |
Why Choose HKS?
- Motorsport-proven components trusted in JDM racing circuits
- Exact tolerances from Japanese factory production
- Advanced materials extend service intervals in demanding conditions
Frequently Asked Questions
- Q: Will this plug fit my RB25DET swap?
A: Yes, direct OEM replacement for stock plugs in R33-R34 Skyline RB25DET engines with no modifications - Q: What material is the center electrode?
A: Pure iridium alloy, 0.4mm diameter for superior spark focus and anti-fouling resistance - Q: What is the warranty and lifespan?
A: HKS 1-year limited warranty. expect 40,000+ miles in street use, longer with proper maintenance
Shipping & Handling
- Method: UPS or FedEx Ground
- Availability: In stock – ships same or next business day
- Packaging: HKS OEM box, 3.1 x 1 x 1 inches
- Weight: 0.1 lbs
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