BMW 440i Performance Exhaust – Dinan Axle Back Freeflow with Helmholtz Chamber, Black (2016–2020). Tuned for a richer, sportier tone and improved flow without unwanted cabin drone.

Developed for the 440i and based on Dinan’s 340i/440i program, this rear section cuts back pressure for sharper response and a confident soundtrack. A Helmholtz chamber targets low‑RPM resonance to curb drone, keeping it calm on the highway yet assertive under throttle. Built from 100% 16‑gauge 304 stainless steel, it installs with factory brackets and hangers. Twin 89 mm (3.5") ceramic black, laser‑engraved tips complete the system. The factory computer‑controlled valve is removed. Verified gains: +6 hp and +5 lb‑ft at 6600 RPM.

Features

• 100% 16‑gauge 304 stainless steel
• Helmholtz chamber reduces drone
• Twin 89 mm (3.5") ceramic black tips
• Uses factory brackets and hangers
• +6 hp / +5 lb‑ft at 6600 RPM

Questions or ready to schedule? Call 512-982-9393 (TX) or 562-981-6800 (CA). We have locations in Austin, Texas and the Los Angeles, California area offering professional installation and customization services.

Purchasing multiple items? Contact us for shipping discounts. We install on premises at both locations.

CA Residents: WARNING: Cancer and Reproductive Harm - www.P65Warnings.ca.gov