TurboXS Catalytic Converter Pipe

TurboXS High-Flow Catalytic Converter Pipes: Performance Without Compromise

When Subaru WRX and STI owners want to liberate power from their turbocharged engines while keeping a catalytic converter in place, TurboXS is one of the most respected names they turn to. The brand has been engineering application-specific performance parts since 1999, and their catalytic converter pipe lineup reflects decades of hands-on development for forced-induction platforms. These aren't generic bolt-ons — each pipe is designed around the specific geometry and flow demands of Subaru's turbocharged engines.

Why the Catalytic Converter Pipe Matters So Much

On a turbocharged Subaru, the factory front pipe (J-pipe) and mid-pipe are widely regarded as the single biggest restriction in the entire exhaust system. Backpressure at this point directly opposes the turbine wheel, robbing it of the pressure differential it needs to spool quickly and push exhaust gases efficiently. Swapping the stock unit for a free-flowing, high-cell-count aftermarket piece is one of the highest-return modifications available — and TurboXS has built their catalytic converter pipe products to maximize that return without sacrificing emissions compliance.

What Sets TurboXS Apart in This Category

TurboXS catalytic converter pipes are constructed from 16-gauge 304 stainless steel throughout, with thick flanges for a leak-free seal and a finish that resists corrosion over the long term. Their high-flow converters use a 100 CPI (cells per inch) metal substrate — a low-restriction cell count that allows exhaust gases to flow far more freely than a stock unit while still treating emissions. The piping itself features strategic diameter transitions: for example, the front pipe for the 2015–2021 WRX steps from 3.5 inches at the turbocharger outlet down to 3 inches at the catback junction, promoting smooth laminar flow rather than turbulence.

The WS08-CP-V2, designed for the 2008–2014 WRX and STI, is a dedicated 3-inch high-flow catalytic converter pipe that slots neatly into the mid-pipe position. For earlier platforms, the WS02-CP serves 2002–2007 WRX, STI, and Forester XT owners. Each pipe is engineered as a direct, bolt-on replacement — no cutting, welding, or custom fabrication required — and ships with the necessary gaskets and hardware to complete installation cleanly.

One practical advantage of the TurboXS modular exhaust approach is flexibility: their high-flow cat pipes are also the primary section used in several TurboXS cat-back systems, meaning they integrate seamlessly into a broader TurboXS exhaust build or can stand alone as an upgrade to an otherwise stock system. A pre-welded O2 sensor bung is included on select fitments for those running aftermarket wideband sensors.

The Bottom Line

For turbocharged Subaru enthusiasts who want meaningful power gains — more horsepower, stronger torque, and reduced turbo lag — without going fully catless, TurboXS catalytic converter pipes represent a well-engineered, durable solution backed by a brand with a long track record in the forced-induction performance space. Explore the full TurboXS brand lineup or browse all catalytic converter pipes to find the right fit for your build.