Performance Exhaust Up Pipes | Turbo Up-Pipes

An up-pipe, also written as up pipe, is the exhaust section that connects the exhaust manifold or cylinder head to the turbocharger’s turbine inlet. It directs hot exhaust gases from the engine to spin the turbo. On certain factory turbo vehicles, especially early Subaru WRX models and some diesel trucks, this pipe may contain a pre-turbo catalytic converter or flex joint that can fail over time.

An up-pipe is located before the turbocharger and sends exhaust gases into the turbo. A downpipe is located after the turbocharger and carries exhaust gases away from the turbo toward the rest of the exhaust system. In simple terms, the up-pipe feeds the turbo, while the downpipe exits the turbo.

Some factory up-pipes contain a restrictive pre-turbo catalytic converter or have flex joints that can crack over time. An aftermarket up-pipe can improve exhaust flow to the turbo, reduce the risk of turbo damage from catalyst debris, and replace aging factory components. Benefits vary by vehicle and factory configuration.

Common signs include exhaust leaks, ticking noises near the turbo, slower turbo spool, reduced boost, burning smells, and visible cracks around the flex joint or welds. On vehicles with a pre-turbo catalytic converter, internal catalyst failure can also create a risk of turbocharger damage.

On vehicles with a restrictive factory pre-turbo catalytic converter, replacing the up-pipe can improve exhaust flow and help the turbo spool more efficiently, which may result in modest horsepower gains. Gains depend on the vehicle, engine setup, tuning, and supporting modifications.

You may notice slightly more turbo spool sound as exhaust flows more freely into the turbocharger. On vehicles where a pre-turbo catalytic converter is removed, the exhaust note can also become a little more aggressive. The change is usually subtle compared with a downpipe or cat-back exhaust.

Tuning depends on the vehicle and up-pipe design. If the pipe removes a pre-turbo catalytic converter, some vehicles may trigger a check engine light due to sensor configuration or ECU calibration. For vehicles with catless factory up-pipes, tuning is usually not required, but it may help maximize gains when paired with other modifications.

Legality depends on the part design and your vehicle’s factory emissions setup. Any up-pipe that removes or bypasses a catalytic converter is intended for off-road, racing, or competition use only and may not be legal for street use. Always check federal, state, and local emissions rules before purchase or installation.

This upgrade is most relevant for 2002–2005 Subaru WRX models because the factory pipe contains a pre-turbo catalytic converter that can deteriorate over time. Replacing it reduces the risk of catalyst debris damaging the turbocharger. Later WRX models and most STI models usually came with catless factory pipes, though an aftermarket option may still help replace aging flex joints or match other exhaust upgrades.

Installation difficulty is usually moderate to high. The pipe sits in a tight area between the engine and turbocharger, often requiring removal of heat shields and nearby components. Rusted hardware is common on older vehicles, so penetrating oil and patience are recommended. Professional installation is advised if you are not experienced with turbo system work.

XKV up-pipes are made from T304 or T409 stainless steel with mandrel-bent tubing for smooth exhaust flow. TIG-welded construction improves durability, while laser-cut flanges help provide a secure, leak-resistant seal. Where applicable, high-quality braided flex joints are used, and most kits include the necessary gaskets and Grade 10.9 hardware.

Fitment is highly vehicle-specific because turbo location, flange design, engine layout, and sensor setup can vary. XKV offers options for select Subaru WRX/STI, Mitsubishi Evo, Ford Powerstroke, and RAM Cummins applications. Use the Year/Make/Model selector at the top of the page to confirm the correct fitment before purchase.