Dinan Valved Axle-Back Exhaust - 2021-2026 BMW M3/M4

Through extensive development and testing nearly every possible permutation of the exhaust was attempted. Unlike the previous generation where cabin sound/drone was largely unchanged between the sedan and the coupe, that was not the case with the G8x chassis'. This caused countless iterations to be attempted in the quest for a common system that not only sounded superb externally but one that also didn't introduce an overbearing internal cabin drone on either body type. The result is a system we are confident will be coveted by all for years to come. To achieve desired sound volume and tone worthy of the G8x M3/M4 the tubing was enlarged to 76mm (vs 70mm stock) to allow freer flow, and reduce backpressure, throughout the entirety of the system. The larger piping gives way to multiple pathways as it nears the rear of the vehicle -- the choice of which is utilized determined by the factory exhaust valves which are retained. When valves are closed, flow is directed into the Dinan muffler, where absorption and reactive technologies are used, and exit out the two inner tips. This limits noise during low-speed driving and produces a more subdued, albeit deeper, and agreeable note. However, when the valves are open during high-load conditions the bulk of the gases bypass the muffler altogether for a near straight pipe design and maximum aural enjoyment to be achieved. It's the perfect marriage for all tastes and allows civility or impassioned aggression depending on what the situation demands. The combination is one Dinan has deemed fitting for the marques signature performance models that cater to the tasteful enthusiast who demand the best for all situations.

Features and Benefits

• Maximum gains of +6 HP and +5 lb-ft of torque
• Enjoyably louder, sportier sound
• Drone abatement technologies used to reduce cabin resonance
• Four, diffuser filling, 4.5-inch (114mm) double-walled, black ceramic coated clamp-on tips with laser engraved Dinan logo
• Larger diameter piping for increased flow (76mm vs. 70mm)
• 6-pounds lighter than the stock axle back (Stock: 44-pounds vs. Dinan: 38-pounds)
• Stock exhaust valve actuators reused, and operation of exhaust valve is unchanged so exhaust tone can be adjusted via the M-drive settings
• Computer controlled exhaust valves are retained and limit noise during low-speed driving and open fully during high-load conditions
• 100% 304 Stainless Steel construction
• Factory-like fitment with included mounting hardware