Active Autowerke Aflow Catted Downpipes - F90 M5 | F9X M8
For over 30 years, Active Autowerke has set the benchmark for BMW performance. The Aflow High-Flow Downpipes are built on that same principle: remove the single largest restriction in the S63TU exhaust path and let the turbos work. Manufactured in-house in Miami, Florida from premium 304 stainless steel and TIG-welded throughout, each downpipe begins with a factory-matched 3.5” V-band inlet that tapers into a high-flow mandrel-bent body. The lower section other manufacturers sell separately as a mid-pipe is included here. OEM O2 sensor heat shield compatibility keeps the engine bay looking untouched. A pair of 4.5” Active Aflow catalytic converters carries a 400 cell per square inch ultra high-flow substrate that reaches operating efficiency within 9 seconds of startup. No CEL for catalytic efficiency, and no performance tune required to run them. The result is stronger power and torque across the band with noticeably less lag. Key Features No CEL for catalytic efficiency, guaranteed Active Aflow high-flow cats, EPA registered and OBD2 compliant (49 states) 4.5” catalytic converters with 400 cpsi ultra high-flow substrate Factory-matched 3.5” V-band inlet into mandrel-bent body Includes the lower mid-pipe section Faster turbo spool and improved throttle response 304 stainless steel with TIG-welded construction Direct bolt-on fit, no cutting or welding Retains OEM O2 sensor heat shield for a stealth look Rated for up to 800 HP applications Withstands up to 1500°F Reaches operating efficiency within 9 seconds of startup Made in Miami, Florida 5-Year / 50,000-Mile Warranty on shell and tube ends, 2-Year / 25,000-Mile Warranty on catalytic core Vehicle Fitment BMW M5 (F90) and M8 (F91 Convertible, F92 Coupe, F93 Gran Coupe), including Competition Not legal for sale or use on pollution-controlled motor vehicles registered in California per California Vehicle Code sections 27156 and 38391. Warranty on the catalytic core is void if the vehicle produces burble or overrun fueling in excess of stock, which physically destroys the catalyst.