NGK ILFR7H 5245 Laser Iridium Spark Plug Mitsubishi Lancer Evo Subaru WRX STI

Vehicle Fitment

• 2006 Mitsubishi Lancer (ES, SE, OZ Rally, Ralliart, 2.0L I4)
• 2006 Mitsubishi Lancer Evolution (Base, RS, SE, MR, 2.0L I4 Turbo 4G63T)
• 2018-2021 Subaru WRX STI (Base, Limited, 2.5L H4 Turbo EJ257)
• 2019 Subaru WRX STI S209 (2.5L H4 Turbo EJ257)

Fitment Notes

• Mitsubishi fitment covers the naturally aspirated 2.0L 4G94 (Lancer ES/SE/OZ Rally/Ralliart) and the turbocharged 2.0L 4G63T (Lancer Evolution) - both use this plug for the 2006 model year only.
• Subaru WRX STI fitment applies to the 2.5L EJ257 turbocharged boxer engine in the 2018-2021 model years only; earlier WRX STI years use different plugs.
• Does not fit the standard Subaru WRX (non-STI) - the WRX uses a different plug specification.
• Pre-gapped at 0.024" (0.6mm) from factory; always verify gap before installation. Do not use plier-style gappers on fine-wire iridium tips.
• Sold individually (1x plug per unit); 4 plugs required per vehicle.

Features

• Laser-welded fine wire iridium center electrode (0.6mm tip) delivers a precise, stable spark with reduced voltage requirements for improved combustion efficiency.
• Taper-cut platinum ground electrode minimizes electrical quenching effect for better flame kernel development and throttle response.
• Heat Range 7 - stock OEM heat range for both confirmed applications - ensures proper electrode temperature management under turbocharged operating conditions.
• Trivalent metal shell plating provides superior anti-corrosion and anti-seizing properties for clean, damage-free removal from aluminum heads.
• High-grade pure alumina ceramic insulator and 98% pure copper core prevent overheating while maintaining reliable cold-start performance.
• Built-in 5K Ohm resistor suppresses EMI/RFI interference to protect sensitive engine management electronics.
• Projected tip design promotes more efficient ignition and improved combustion in the cylinder bore.
• OE-equivalent design tested to meet factory service interval and ignition system specifications for both Mitsubishi and Subaru applications.

Specifications

• NGK Part Number: ILFR7H
• NGK Stock Number: 5245
• Plug Type: Laser Iridium (Single Iridium Tip / Platinum Ground)
• Thread Diameter: 14mm
• Thread Pitch: 1.25mm
• Seat Type: Flat (Gasket)
• Thread Reach: 26.5mm (1.04")
• Hex Size: 5/8" (16mm)
• Terminal Type: Solid
• Pre-Set Gap: 0.024" (0.6mm)
• Center Electrode Material: Iridium Fine Wire - 0.6mm
• Center Electrode Tip: Projected
• Ground Electrode: Platinum Taper Cut
• Resistor: Yes - 5,000 Ohm
• Manufacturer Heat Range: 7
• Torque Spec (Cast Iron): 18-25.3 lb-ft
• Torque Spec (Aluminum): 18-21.6 lb-ft

Included Components

• 1x NGK ILFR7H Laser Iridium Spark Plug (pre-gapped at 0.024" / 0.6mm)

Product Description

The NGK ILFR7H (Stock No. 5245) is a Laser Iridium spark plug engineered as the OEM-equivalent replacement for two high-performance turbocharged applications: the 2006 Mitsubishi Lancer Evolution with the 4G63T engine, and the 2018-2021 Subaru WRX STI with the EJ257 boxer engine including the limited-edition S209. Running at stock Heat Range 7, this plug is designed to manage electrode temperatures correctly under factory boost levels while providing the ignition consistency that turbocharged engines demand. The laser-welded 0.6mm fine-wire iridium center electrode paired with a taper-cut platinum ground electrode delivers a clean, focused spark with significantly less voltage draw than conventional plugs.

The projected tip design and narrow 0.024" pre-set gap are purpose-built for the tight combustion chamber geometries of these high-revving, high-compression engines. Installation is straightforward - plugs come pre-gapped and require no additional adjustment under stock configuration. Four plugs are needed per vehicle, and NGK recommends replacing all plugs as a set to maintain balanced cylinder performance. As the actual OEM or equivalent plug for these platforms, the ILFR7H is the definitive choice for routine maintenance or post-modification re-gapping at the factory service interval.