The Dinan Free Flow Axle-Back Exhaust is built entirely from TIG-welded, brushed T304 stainless steel and runs larger 76mm tubing versus the 70mm stock piping for freer flow. A dual-valve design adds a second 76mm computer-controlled valve so gas flows evenly regardless of valve position, with valves roughly 30% less restrictive than the OE units that open under load for an aggressive, near straight-pipe tone and close at low speed for a civil cabin. Quad 4in double-walled, black ceramic-coated, laser-engraved tips finish the system. Dinan rates gains of +6 HP and +5 lb-ft at 6600 RPM, and the system is about 4 lbs lighter than stock. Installation is bolt-on with the included mounting hardware.
| Type | Free Flow axle-back exhaust (dual-valve) |
| Material | T304 stainless steel, TIG welded, brushed |
| Tips | Quad 4in double-walled, laser-engraved |
| Finish | Black ceramic-coated tips |
| Valves | Dual 76mm computer-controlled (30% less restrictive than OE) |
| Piping Diameter | 76mm (vs 70mm stock) |
| Power Gain | +6 HP & +5 lb-ft @ 6600 RPM |
| Part Number | D660-0085-BLK |
Documents: Installation Instructions (PDF)
This part fits:
| Year | Make | Model | Submodel |
|---|---|---|---|
| 2020-2026 | BMW | M340i | Base |
| 2020-2026 | BMW | M340i xDrive | Base |
| 2021-2026 | BMW | M440i | Base |
| 2022-2024 | BMW | M440i Gran Coupe | Base |
| 2021-2024 | BMW | M440i xDrive | Base |
| 2022-2024 | BMW | M440i xDrive Gran Coupe | Base |
Shipping: In-stock orders placed before 3 PM EST ship the same day, and everything else ships within 24 hours. Standard, expedited, and overnight options are available at checkout. Backordered items ship as soon as we get them back in stock. Contact us for lead times. See the full Shipping Policy.
Returns: 30-day returns on new, unused items in original packaging. See the full Refund Policy.
