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2008-2014 Subaru WRX spark plug & gap

The WRX came with more than one engine, and they don't all take the same plug. Find your engine below for the exact part number, gap, and where to buy it.

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2.5L H4 · 2008-2014EJ255

Spark plug part number

  • NGKSILFR6A(heat range 6 — NGK scale)
  • DensoIKH20(heat range 20 — Denso scale)

Confirmed from NGK + Denso · verified Jul 2026.

Gap

0.031 in (0.79 mm)

We don't stock a reviewed plug for this engine yet. Search the confirmed part number on Amazon — it's the safest way to land on the right plug.

Find NGK SILFR6A on Amazon
Where this came from
  • NGK.com NGK 7913 SILFR6A application page — source
  • DensoProducts.com Denso 5344 IKH20 application page — source

2.5L H4 · 2008-2014EJ257

Spark plug part number

  • DensoIKH20(heat range 20 — Denso scale)
  • NGKSILFR6A(heat range 6 — NGK scale)

Cross-verified via part catalogs.

We don't stock a reviewed plug for this engine yet. Search the confirmed part number on Amazon — it's the safest way to land on the right plug.

Find Denso IKH20 on Amazon

Part number and gap confirmed against two independent maker sources — never changed by what an affiliate link pays us. Heat range is shown per brand on purpose: a Denso number and an NGK number don't mean the same thing, so never compare them directly. Your owner's manual is always the final word.