The Active Autowerke B58 downpipe for the 340i and 440i helps unleash some of the potential that is restricted by the OEM downpipe.
Turbochargers are powered by spent exhaust gases created during the combustion process. The quicker these gases are evacuated, the better. Unfortunately, the factory down pipe in the B58 is quite restrictive, which results in slower exhaust gases and slower turbo spool.
The Active Autowerke F-Chassis B58 Signature down pipe utilizes 4.5” diameter stainless steel piping in order to provide more power, quicker spool, and extreme durability. It then tapers down to 3.5″ where we’ve incorporated a stainless flex joint and then down to 80mm to meet the OEM exhaust system. We never drop the diameter less than the stock diameter of 80mm.
The GESi® G-Sport Ultra High Output Catalytic Converter features full 304 stainless steel construction, including the substrate. GESi® UHO-Series Catalytic Converters are EPA certified in 49 states and fully OBD2 compliant, perfect for use on 1996 and newer vehicles. GESi® proprietary precious metal loading technology ensures greatly reduced emissions, eliminating most “Check Engine Lights”. These high flow catalytic converters outperform stock converters and provide a reliable solution to the most common catalytic converter problems.