Catalytic Converter for Subaru WRX STI (2015-2018) 2.5L

Direct-Fit Catalytic Converter for 2015-2018 Subaru WRX STI (VA)

What it Does: This direct-fit catalytic converter replaces the turbo-outlet pipe on 2015-2018 Subaru WRX STI (VA) EJ257 2.5L models to restore emissions control and flow.

The Stock Subaru WRX STI Catalytic Converter Failure

On the VA chassis with the turbocharged EJ257 2.5L boxer, the factory converter sits directly behind the turbocharger outlet under extreme exhaust heat. Repeated thermal cycling degrades the precious-metal washcoat and fractures the ceramic honeycomb substrate. Loose substrate pieces restrict exhaust flow and raise backpressure. Downstream oxygen sensors then mirror upstream readings, triggering catalyst efficiency faults and metallic rattles.

Common Symptoms of a Failing OEM Converter

• Check Engine Light: Stored P0420 or P0430 codes from lost catalyst oxygen storage.
• Exhaust Rattle: Metallic rattling from fractured ceramic substrate inside the converter housing.
• Backpressure & Emissions Failure: Plugged honeycomb cells hurt turbo spool and fail smog tests.

The Direct-Fit Stainless Catalytic Converter Solution

Built with corrosion-resistant stainless steel (8 in length, 5 in height), this converter resists rust and heat cracking. Its ceramic honeycomb substrate uses a precious-metal washcoat to convert HC, CO, and NOx gases. Factory-matched turbo outlet, bracket, and 2-bolt rear flanges ensure direct bolt-on fitment without cutting or welding. This unit features no O2 sensor ports.

What's Included

• 1 x Catalytic Converter (SRCZ004/2)
• 1 x Turbo Flange Gasket
• 1 x 2-Bolt Flange Gasket
• 4 x Bolts, Nuts, Washers

Technical Specifications

Compatibility

• 2015-2018 Subaru WRX STI Base (2.5L Turbo)
• 2015-2018 Subaru WRX STI Limited (2.5L Turbo)
• 2015 Subaru WRX STI Launch Edition (2.5L Turbo)
• 2016 Subaru WRX STI Series.HyperBlue (2.5L Turbo)

Frequently Asked Questions & Fitment Warnings

Does this fit the VA WRX STI?

Yes. Fits 2015-2018 Subaru WRX STI EJ257 2.5L models. Excludes 2.0L WRX. Not CARB approved; illegal in CA, NY, CO, and ME.

Will this clear P0420/P0430 codes, and are O2 sensors included?

Yes, if converter-related. Restored catalyst efficiency clears P0420/P0430 codes after checking leaks and sensors. O2 sensors are excluded; reuse or replace yours.

Are gaskets and hardware included for installation?

Yes. Gaskets and four bolts, nuts, and washers are included. Cool the exhaust, soak studs with penetrating oil, and torque evenly.

The Subaru Performance Standard

Engineered for the EJ257 platform, this converter restores clean exhaust flow efficiency and reliable emissions control. Maintain strong spool and crisp throttle response.