BMW introduced a new valvetronic, single turbo version of its direct-injection engine for the later F-Chassis models beginning in 2016 and carried over to the G-chassis models. 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.
This variant includes a 4.5" high flow GESI catalytic converter that will NOT produce a CEL!
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 registered and compliant 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.
The GESi UHO-Series Catalytic Converters are rated for engines putting out between 500 and 850 horsepower while maintaining a high flow capacity. The reduced back-pressure from this high flow catalytic converter will allow you to maximize your engines horsepower without the harmful emissions. Say goodbye to Check Engine Lights and failed emissions tests!
 
KEY FEATURES
NO CEL for catalytic efficiency when using this downpipe
GESI EPA registered high flow and fully OBD2 compliant
Casted upper stainless steel V-Band for precise fitment
4.50" diameter piping allows for maximum power output
Quicker turbo spool
Rated for 500 to 850 hp applications
Withstands up to 1500 F
Can reach operational efficiency within 9 seconds of startup
Easily bolts-on - no cutting or welding required
Durable construction from TIG welded 304 stainless steel
Precise fitment
Ultra high flow 400 cell per square inch catalyst
EPA compliant for use on OBD2 vehicles (1996 and newer) except in California
304 stainless steel substrate is furnace braised to the mantle for outstanding durability
GESi proprietary precious metal loading technology ensures greatly reduced emissions
Ideal for Forced Induction Applications with no loss of HP
Both passengers and drivers are safe from harmful emissions and noise
Covered by 5 Year / 50,000 Mile Warranty (on shell and tube ends) and 25,000 Mile Warranty on the Catalytic core
Made in Miami, Florida
APPLICATIONS
2016+ M240i 340i 440i