4 SERIES G22 / G23 / G24

Catback exhausts, downpipes and carbon parts for the BMW 4 Series G22, G23 and G24

On the BMW 4 Series G22, choosing an exhaust starts with the engine. The 420i and 430i use the B48 and the M440i uses the B58; both engines have Valvetronic catback exhausts in stainless steel or titanium. B48 cars also have downpipes to choose from. For the exterior there is a prepreg dry carbon fiber mirror cap set, and for the cabin magnetic carbon fiber paddle shifters. Most of these parts are shared with the 3 Series G20, which is why both chassis appear in the product names. BYC Performance imports all of them from leading manufacturers around the world.

Valvetronic catback exhausts for the B48 and B58

A catback replaces the whole line after the downpipe, all the way to the tips. The B48 and B58 systems are not interchangeable, so check your car's engine first. The 420i and 430i take the B48 stainless steel or B48 titanium catback, and the M440i takes the B58 stainless steel or B58 titanium catback.

Each system comes with its own electronic control box and wireless remote. With the valves closed the exhaust runs quieter, and it gets louder when you open them with the remote. The titanium versions are lighter than stainless steel and come in gold, blue, purple or original titanium color. Whatever the material, you choose the tips: carbon fiber tips come in gloss or matte finish, and gloss black and stainless steel tips are also available.

B48 downpipe options

The downpipe is the pipe that carries exhaust from the turbocharger to the rest of the system. The B48 downpipes are heat-shielded stainless steel: the 200-cell catted downpipe has a catalytic converter and the de-cat downpipe does not. Before buying the de-cat model, check whether an exhaust without a catalyst is allowed where your car is driven. Whether the car needs software after a downpipe depends on the car, so ask on WhatsApp. There is no downpipe option for the M440i's B58 engine.

Convertible, Gran Coupé and the M4

For the 4 Series, the product names list only the G22 Coupé. If you own a G23 Convertible or a Gran Coupé, confirm fitment with your VIN on WhatsApp before ordering. No diesel engine appears in the product names either. The M4 G82 and G83 have the S58 engine and M-specific body parts, so these exhausts, downpipes and mirror caps do not fit the M4; M4 parts are in the M4 G82 / G83 category.

Frequently asked questions

How do I know whether my car has the B48 or the B58?

The 420i and 430i have the B48, and the M440i has the B58. If you are not sure, send your VIN on WhatsApp and the BYC team will check the engine code before you order.

Can I work the valves with the car's own exhaust button?

The wireless remote supplied with the system opens and closes the valves, not the car's original button.

Do these parts fit other BMWs too?

The catbacks, downpipes and mirror cap set also list the 3 Series G20, and the B58 catback also names the 2 Series G42. Other parts for those cars are in the 3 Series G20 / G21 and 2 Series G42 categories.

When does the exhaust ship, and is there a warranty?

Lead time for sourced-to-order parts is confirmed on WhatsApp right after your order. Every part, exhausts included, ships via partner couriers and carries a 24-month BYC warranty against manufacturing defects.