The Dinan D660-0085-BLK Free Flow Axle-Back Exhaust system gives the BMW M340i and M440i a true M-style presence with quad 4 in. ceramic black exhaust tips and twin-valve sound control. Constructed from TIG-welded T304 stainless steel with brushed finish and larger 76mm piping, it delivers both performance and premium acoustics. A second electronic valve is added for even exhaust flow and more aggressive tone under load, while internal muffling and drone-abatement design preserve cabin comfort during low-speed cruising. The result is a deeper, freer-flowing sound that enhances the factory platform without compromising refinement. Clamp-on tips with laser engraving complete the system's aggressive styling.

Dinan D660-0085-BLK Free Flow Axle-Back Exhaust Features:

• +6 HP and +5 lb-ft torque gains at 6600 RPM
• Quad 4 in. clamp-on double-wall ceramic black exhaust tips
• 100% 304 stainless steel TIG-welded construction
• 76mm piping replaces stock 70mm for improved flow
• 4 lb weight reduction vs. factory system
• Dual 76mm electronic exhaust valves for symmetrical flow
• Reuses OEM valve actuator and adds second actuator for enhanced control
• Improved sound during acceleration, quiet operation under low-load conditions
• Drone-abatement muffler tech maintains interior comfort
• Direct bolt-on installation with included mounting hardware

Emissions Note:

This part is legal for sale or uses on Emissions Controlled Vehicles, Uncontrolled (Non-Emissions Controlled) Vehicles, and Racing Use Only Vehicles because it does not affect vehicle emissions and is not covered by emissions regulations.

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