Description
Upgrade the exhaust flow, sound, and overall character of your G8X BMW M3 or M4 with the MAD 4-Inch FATBOY Single Midpipe, specifically engineered for the S58-powered G80, G82, and G83 platforms.
Designed around the principle that flow is everything, the FATBOY Midpipe features a full-length single 4-inch center section with a minimum 3-inch pipe diameter throughout the system. This high-flow configuration is designed to reduce exhaust flow restrictions and provide a smoother, more efficient path for exhaust gases from the downpipes toward the rear exhaust system.
Beyond its performance-focused design, the MAD FATBOY Midpipe delivers a deeper, more aggressive, and refined exhaust tone while helping reduce the excessive rasp commonly associated with modified G8X exhaust systems. It is an excellent choice for enthusiasts looking to enhance the sound of their S58 without sacrificing everyday drivability.
The FATBOY Midpipe can be paired with either stock or aftermarket downpipes, giving you flexibility when building your exhaust setup. Its single 4-inch center section is designed to maintain strong exhaust flow, while the included reducer couplers allow the midpipe to connect to compatible 3-inch aftermarket axle-back systems or factory axle-back systems.
Installation is designed to be straightforward and reversible. The system utilizes the OEM cut location and factory-style clamp design, minimizing installation complexity and allowing the vehicle to be returned to its original configuration if desired.
The kit also includes the MAD Extended Chassis Brace, along with the necessary reducer couplers for compatible axle-back configurations.
Key Features
- Designed specifically for the BMW G8X M3/M4 S58 platform
- Full-length single 4-inch center section
- Minimum 3-inch pipe diameter throughout
- High-flow design engineered to maximize exhaust flow
- Deeper and more aggressive exhaust tone
- Helps reduce excessive exhaust rasp
- Refined sound suitable for both street and track applications
- Compatible with stock or aftermarket downpipes
- Includes MAD Extended Chassis Brace
- Includes 3-inch and 2.75-inch reducer couplers
- Compatible with 3-inch aftermarket axle-back systems, including MAD systems
- Can connect to compatible factory axle-back systems
- Uses the OEM cut location and clamp design
- Installation is designed to be easy and reversible
Exhaust Sound & Performance
The MAD FATBOY Midpipe is designed to give the S58 engine a more pronounced exhaust character while maintaining efficient exhaust flow. The larger single-pipe configuration helps minimize unnecessary restrictions and provides a deeper, more refined exhaust note.
When combined with aftermarket downpipes, the FATBOY Midpipe can further transform the sound and character of the G8X platform while its design focuses on reducing the harsh rasp often associated with aggressive exhaust modifications.
Installation Note
Downpipe gaskets are not included. Installation requires 2 × BMW OEM downpipe gaskets, part number 18308053348.
Fitment
- 2021+ BMW G80 M3
- 2021+ BMW G82 M4
- 2021+ BMW G83 M4
Engine: BMW S58
Chassis: G80 / G82 / G83
Configuration: Single 4-inch midpipe
