GESI Catted Downpipe

The Active Autowerke BMW G2X G4X B58 M340i M440i GESI Catted Downpipe is engineered to unleash the performance potential of the BMW B58 engine by alleviating restrictions found in the OEM downpipe. This component is constructed from durable, full 304 stainless steel with 1.5MM wall thickness and features a 4.5-inch diameter primary pipe that tapers to meet the OEM exhaust system. This design significantly reduces exhaust back-pressure, promoting quicker turbo spool and enhancing overall engine responsiveness. Central to this downpipe is the GESI G-Sport Ultra High Output (UHO) catalytic converter. This EPA-registered and OBD2-compliant unit boasts a 400-cell per square inch density and is designed to efficiently reduce emissions while minimizing performance impact. It is rated for engines producing between 500 to 850 horsepower and can reach operational efficiency within 9 seconds of startup. The catalytic converter's construction includes a 304 stainless steel substrate, furnace-braised for durability and capable of withstanding temperatures up to 1500°F. The downpipe includes a cast upper stainless steel V-band for precise fitment and comes with a turbo flange gasket, with Active Autowerke now installing it to prevent customer installation damage. Notably, this downpipe does not require a performance tune for operation. However, it is explicitly stated that fitment applies to US model cars only, and fitment to non-US model cars cannot be guaranteed. Additionally, these catalytic converters are not legal for use on vehicles registered in California. This downpipe is backed by 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. The warranty is void if the vehicle has excessive burble beyond stock, as this can physically damage the catalytic core. The product is manufactured in Miami, Florida.