How many catalytic converters does a Subaru WRX have?
Two catalytic converters. The WRX’s exhaust system typically includes a close-coupled pre-catalytic converter near the turbo and a downstream main catalytic converter, totaling two. While this two-cat setup is standard for most WRX models, variations can occur by generation and market.
Standard layout and how it works
In the typical WRX exhaust path, exhaust gases flow from the turbo into a pre-catalytic converter (the close-coupled cat) to reduce emissions early and help heat the catalyst. The gases then pass through a second catalytic converter further downstream (the main cat) before continuing to the exhaust system and tailpipe. This arrangement allows for effective emissions control and quicker warm-up of catalysts.
In many generations, the two converters are located in series along the exhaust downpipe or mid-pipe assembly, with the pre-cat often integrated into the exhaust manifold or right after the turbo, and the main cat placed downstream along the pipe.
- Close-coupled pre-catalytic converter near the turbocharger or exhaust manifold, designed to heat up quickly and begin emissions reduction early in the exhaust stream.
- Downstream main catalytic converter located in the downpipe or mid-pipe, providing the primary catalytic activity as exhaust leaves the engine system.
To illustrate the common layout on most WRX models, the following two catalytic converters are typically present:
This two-converter layout is standard for most WRX models, though some regional versions or earlier-generation designs may diverge slightly in placement or integration with the exhaust manifold.
Variations by model year and market
Subaru has used multiple engine designs in the WRX lineup, from earlier EJ-series turbo engines to more recent FA-series 2.4L units. In the vast majority of these, two catalytic converters are present. However, exact placement, integration with the turbo, and the presence of additional small catalysts (for certain region-specific regulations) can vary. If you need a precise count for your exact VIN or model year, check the official service manual or consult a Subaru dealership.
Maintenance and inspection tips
When inspecting or replacing catalytic converters, consider these points:
- Replacement parts: Many WRX owners replace both the pre-cat and main cat together as part of a downpipe or exhaust system upgrade, especially in performance builds.
- Regulatory considerations: Emissions requirements vary by region; some areas require specific configurations or sensor placements (oxygen sensors upstream/downstream).
- Symptoms of failing cats: Reduced power, increased exhaust emissions, check engine light, rattling, or a noticeable drop in fuel economy; if you suspect a cat problem, have a professional diagnose with diagnostic tools and a backpressure test.
Before replacing parts, owners and technicians typically verify the arrangement on the specific model year and market, as variations can exist.
Always verify the exact layout for your vehicle’s year and market, as Subaru has issued changes over time.
Summary
In concise terms, a Subaru WRX commonly houses two catalytic converters in the exhaust system: a close-coupled pre-catalytic converter near the engine and a downstream main catalytic converter. This two-cat setup is standard for the model across many generations, though minor variations can occur by year and region. If you are planning repairs, replacements, or performance mods, confirm the configuration for your specific car with the service manual or a Subaru technician.
