Dinan Free Flow Axle-Back Exhaust - 2016-2020 BMW 340i/440i | D660-0055

The Dinan Free Flow Axle-Back Exhaust (D660-0055) is a precision-engineered upgrade for the 2016-2020 BMW 340i (F30) and 440i (F32), designed to optimize the engine's performance. By reducing back pressure, this system delivers a verified power increase of +6 HP and +5 LB-FT of torque at 6600 RPM. The result is a great sporty sound, enriched with additional burbles and pops, that is pleasantly aggressive under hard acceleration.

Cabin resonance is precisely controlled by an integrated Helmholtz chamber design which specifically reduces resonance or "drone" at low RPM, ensuring civility. The factory computer-controlled exhaust valve is eliminated for maximum, free-flowing sound at all times. The system is built from 100% 16-gauge 304 stainless steel to resist corrosion for years to come.

Features:

• Verifiable Power Gains: Delivers an increase of +6 HP and +5 LB-FT of torque at 6600 RPM.

• Advanced Drone Abatement: Integrates a Helmholtz chamber to reduce cabin resonance, providing an enjoyably louder, sportier sound.

• Superior Material & Construction: Built from 100% 16-gauge 304 stainless steel to resist corrosion and ensure long-term durability.

• Flow Optimized: The factory computer-controlled exhaust valve is eliminated for maximum flow and sound at all times.

• Aesthetic Excellence: Finishes with twin 89mm (3.5") laser engraved, polished stainless exhaust tips (ceramic black tips also available) for a tasteful, high-performance look.

• Fitment Integrity: Built to exacting specifications, using the factory brackets and hangers for a guaranteed, factory-like fitment.

Product Contains:

• (1) Dinan Axle-Back Muffler Assembly

• (2) Twin 89mm Polished Stainless Exhaust Tips

• (1) Complete Installation Hardware Kit

Warranty This product is supported by a Manufacturer's Warranty. Note: Manufacturer warranty terms are subject to change.

Installation Instructions