These are the spark plugs found in the newer 2019+ Subaru STi models with the EJ25 engine.  These are 1-step colder and feature a much tighter spark plug gap which is necessary for modified vehicles.  If you’re making over 300WHP we recommend running these spark plugs over the OEM range plugs.

Why NGK Iridium?
More Durability and a Higher Melting Point compared to Platinum, better center electrode anti-oxidation and anti-erosion, improved ignition, superior anti-fouling, lower required voltage, new metal shell plating process for better anti-corrosion. One Step Colder plugs are recommended for cars with heavy modifications. These Iridium Spark Plugs will get your Turbo Subaru running smoother and free up some power through increased efficiency and increased heat resistance. These are available in stock heat or one step colder for cars running approximately 100 horsepower more than stock.

Please Note:
1. Iridium plugs are able to use a larger gap setting with less voltage. Some customers choose to re-gap these plugs to correct misfiring or tune for optimal spark — do so at your own risk — slide-type plug gapper will damage the fragile iridium tip.

Heat Range:

– Stock Heat Range for Evo 9
– Stock Heat Range for 2019-2020 STi
– One-Step Colder for all other Turbo EJ25 Subaru

• Thread Diameter – 14mm
• Thread Pitch – 1.25mm
• Seat Type – Gasket
• Reach – 26.5mm (1.04″)
• Hex Size – 5/8″ (16mm)
• Terminal Type – Solid
• Overall Height – ISO
• Gap – .024″ (0.6mm)