Description
The MAD BMW M340 / M440 Axle Back Exhaust System (G20 & G22) is engineered to deliver a bold and refined exhaust sound upgrade without unnecessary parts or added cost. Compared to a full catback system, this updated axle-back design is more cost-effective, easier to install, and focuses specifically on the section of the exhaust that directly impacts sound and driving feel.
On the BMW M340i and M440i platform, a full catback exhaust is not required. The factory midpipe is already a straight-through, non-restrictive design with no catalytic converters or resonators, meaning there is minimal to no performance or sound gain from replacing it. This makes the axle-back section the most effective area for meaningful improvement.
This system delivers a deeper, more aggressive exhaust tone under acceleration while maintaining OEM-level refinement during normal driving conditions. It enhances driving enjoyment without sacrificing comfort.
A key upgrade is the conversion from the factory single-valve setup to a true dual M-style valve system. It uses the OEM valve motor and includes an additional valve and wiring harness, allowing seamless integration with factory electronics. The exhaust continues to operate fully with OEM drive modes, remaining quiet in Comfort mode and opening fully in Sport mode.
Installation is designed to be straightforward using OEM BMW designated cut points. This allows for a clean installation and also ensures the system can be reverted back to stock if needed using OEM BMW sleeve clamps (Part numbers: 18307560781 & 18307560780).
Constructed from premium 304L stainless steel, this system is built for durability, corrosion resistance, and long-term performance. It is available with multiple exhaust tip finishes to match different styling preferences.
Features
- More cost-effective and easier to install than full catback systems
- Aggressive exhaust tone upgrade with refined daily drivability
- Retains factory midpipe for optimal balance of sound and flow
- True dual M-style valve system with OEM valve motor and included harness
- Fully compatible with OEM drive modes (Comfort and Sport functionality retained)
- Premium 304L stainless steel construction for durability
- Larger 76mm piping vs factory 70mm for improved exhaust flow
- Available tip options: brushed stainless, black, or carbon
- Cut-and-clamp installation using OEM BMW cut points
- Fully reversible installation using OEM sleeve clamps
Fitment Includes
- BMW M340i G20 2018+
- BMW M440i G22 Coupe 2018+
- BMW M440i G26 Gran Coupe 2021+
- BMW M340i / M440i 2025+
- Compatible with RWD and xDrive models
Upgrade your BMW M340i or M440i with the MAD Axle Back Exhaust. Features a deeper aggressive tone, dual M-style valves, 304L stainless steel construction, OEM compatibility, and easy cut-and-clamp installation.
