The Subaru WRX exhaust runs from the turbocharger through a downpipe (sometimes called a J-pipe on some generations), a front pipe with catalytic converters, a mid-pipe or resonator section, and a cat-back with the muffler and tips. A cat-back is the most common upgrade for sound and weight, while turbo-side changes affect power and need engine calibration. The famous Subaru rumble comes from unequal-length headers on EJ engines; the FA-engine WRX uses equal-length headers and sounds smoother.
WRX exhaust system layout
| Section | What it does |
|---|---|
| Headers / up-pipe | Collect exhaust from the boxer engine and feed the turbo |
| Downpipe | Carries exhaust away from the turbo; contains or leads to a catalytic converter |
| Front and mid pipe | Catalytic converters and resonators on many models |
| Cat-back | Pipes, muffler and tips after the converters |
WRX exhaust sound: EJ vs FA
EJ-powered WRX and STI models (through 2014 for the WRX and 2021 for the STI) use unequal-length headers, which give the uneven “boxer rumble”. The 2015-and-later WRX with the FA engine uses equal-length headers, so its exhaust note is smoother and a cat-back mostly changes volume and tone rather than adding the rumble. See EJ255 vs EJ257 and FA20 vs FA24.
Choosing a WRX cat-back
- Body style: sedan and hatchback cat-backs differ; check the listing.
- Sound level: touring versions drone less than track versions; see exhaust drone.
- Material: titanium saves weight; see titanium vs stainless exhaust.
- Tips: quad tips are standard on many WRX and STI models.
WRX exhaust leaks and rattles
A ticking that rises with rpm on a WRX is often an exhaust leak at the up-pipe, downpipe or flange gaskets, and a rattle over bumps is usually a loose heat shield. Leaks ahead of the oxygen sensors can also upset fueling; see O2 sensor and engine ticking noise.
Installing a cat-back
Cat-backs bolt to the existing flange behind the catalytic converters and hang from the factory rubber hangers. With the car safely on ramps or jack stands, soak the old bolts with penetrating oil, support the old system as you unbolt it, fit new gaskets, hang the new system loosely, align the tips evenly in the bumper cutouts and then tighten everything. Recheck clamps and hangers after the first drive, because systems settle as they heat up.
Does a WRX exhaust add power?
A cat-back adds little power by itself; turbo-side parts and calibration make the real difference. Keep emissions equipment in place and check your state’s rules; see does exhaust add horsepower?
WRX cat-backs we carry
- MAPerformance cat-back, 2015-2021 WRX/STI: $999.99
- AWE Track Edition, 2011-2021 WRX/STI sedan: $1,195.00
- Tomei Expreme Ti titanium cat-back: $1,161.00
See Subaru WRX and STI parts, and if an engine has failed, our built EJ25 and FA20/FA24 blocks.
More guides: resonator vs muffler · WRX vs STI · AWE Track vs Touring.
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