B46/B48 Catted Downpipe

The Active Autowerke BMW B46/B48 Catted Downpipe is engineered to overcome the restrictive nature of the factory downpipe in F-Chassis BMW models beginning in 2016. By utilizing a 3-1/2 inch diameter 304 stainless steel piping, this downpipe facilitates quicker exhaust gas evacuation, leading to improved turbo spool, increased horsepower, and enhanced torque. This downpipe incorporates a high-flow, 4-inch GESI catalytic converter, which is EPA registered and compliant in 49 states, making it suitable for OBD2 compliant vehicles (1996 and newer) excluding California. The GESI HO-Series Gen 2 converter is rated for engines between 300-500 horsepower and is designed to minimize emissions, thus preventing most Check Engine Lights (CELs). Installation is straightforward with a bolt-on design requiring no cutting or welding. The downpipe is constructed from TIG welded 304 stainless steel with a 1.5mm wall thickness for robust durability and longevity. It features a cast upper stainless steel V-Band for precise fitment and a stainless flex joint for integration with the OEM exhaust system. Important notes for installation and fitment: Active Autowerke advises that no performance tune is needed for this downpipe. The gasket is pre-installed into the downpipe flange to prevent damage during installation. Fitment is confirmed for US model cars; compatibility with non-US models cannot be guaranteed. Additionally, use of this downpipe is not legal for vehicles registered in California. The product comes with a 5-year/50,000-mile warranty on the shell and tube ends, and a 2-year/25,000-mile warranty on the catalytic core, void if excessive burble causes damage.