Dinan Free Flow Axle-Back Exhaust - BMW M340i / M440i (G20/G22) 2020-2026 - Black Tips

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.

Specifications

Documents: Installation Instructions (PDF)

This part fits:

Shipping

• In-stock orders placed before 3 PM EST ship the same day — everything else ships within 24 hours.
• Standard, expedited, and overnight options at checkout.
• Oversized items ship by freight and take longer.
• Backordered items ship as soon as stock lands — contact us for lead times.
• International orders: prices do not include VAT, duties, or import fees. Your country charges these at import and they are the buyer’s responsibility.

Returns

• 30-day returns on new, uninstalled items in original packaging with all hardware.
• Standard returns: 8% restocking fee, buyer pays return shipping. Both waived if the item is defective or we made the error.
• Installed or used parts can’t be returned — confirm fitment before you install.
• Special orders and custom items are final sale.
• Email us for return authorization before shipping anything back.

Full details: Shipping Policy · Refund Policy