Dinan Free Flow Axle-Back Exhaust for 2020-2026 BMW M340i/M440i - D660-0085-BLK

Give your BMW M340i or M440i a deeper exhaust note, freer-flowing exhaust path, and distinctive quad-tip appearance with the Dinan D660-0085-BLK Free Flow Axle-Back Exhaust. Designed for select 2020-2026 BMW M340i and 2021-2026 M440i applications across the G20, G22, G23, and G26 chassis, this system is constructed from TIG-welded T304 stainless steel and finished with four 4-inch black ceramic coated, double-wall, straight-cut exhaust tips. Dinan uses larger 76mm piping versus the factory 70mm system and reports gains of up to 6 HP and 5 lb-ft of torque at 6,600 RPM.

Unlike the factory single-valve configuration, the Dinan system incorporates twin 76mm exhaust valves to provide balanced flow across both sides of the exhaust. The factory exhaust valve actuator is reused, while an additional valve and actuator are added to the opposite side. With the valves open, exhaust is directed through the freer-flowing outer outlets for a louder, deeper tone. With the valves closed, exhaust gases are routed through the muffler and exit the inner tips to reduce sound during lower-speed driving. Dinan's internal drone-abatement design helps maintain a more comfortable cabin while delivering a sportier exhaust character under load.

Key Features & Specs:

• Brand: Dinan
• Product Type: Free Flow Axle-Back Exhaust
• Part Number: D660-0085-BLK
• Chassis: G20 / G22 / G23 / G26
• Body Material: T304 Stainless Steel
• Pipe Material: T304 Stainless Steel
• Construction: TIG-Welded
• System Finish: Brushed
• Tip Finish: Black Ceramic Coated
• Exhaust Tip Quantity: 4
• Tip Diameter: 4 in / 102mm
• Tip Style: Straight-Cut, Double-Wall, Clamp-On
• Tip Branding: Laser Engraved
• Exhaust Piping: 76mm vs. 70mm stock
• Exhaust Valves: Dual 76mm computer-controlled valves
• Valve Flow: Dinan states the 76mm valves are 30% less restrictive than the OE valves
• Valve Operation: Retains computer-controlled functionality for quieter low-speed driving and increased sound under high-load conditions
• Factory Actuator: Reused
• Additional Actuator: Second valve / actuator added to opposing side
• Maximum HP Gain: +6 HP at 6,600 RPM
• Maximum Torque Gain: +5 lb-ft at 6,600 RPM
• Weight Reduction: 4 lb lighter than stock
• Sound: Louder, deeper, sportier exhaust tone
• Drone Control: Designed with drone-abatement features for improved cabin comfort
• Installation: Bolt-on
• Mounting Hardware: Included
• Clamps Included: Yes
• Hangers Included: Yes
• Labor Time: 2.5 hours
• Length: 54 in
• Width: 29 in
• Height: 10 in
• Weight: 68 lb
• Grade Type: Performance
• Dinan Point Value: 3
• Emission Code: 5
• UPC: 813725028774
• Alternate Finish: Polished-tip version available as Dinan D660-0085

Fitment:

• 2020-2026 BMW M340i
• 2020-2026 BMW M340i xDrive
• 2021-2026 BMW M440i
• 2022-2024 BMW M440i Gran Coupe
• 2021-2024 BMW M440i xDrive
• 2022-2024 BMW M440i xDrive Gran Coupe