Dinan Carbon Fiber Turbo Inlet Pipe BMW M340i/M440i Gen 3 B58 2025+ - Direct OE Replacement

Dinan lists this carbon fiber turbo inlet pipe for the 2025 and newer BMW M340i and M440i built with the Gen 3 B58 engine (B58TU2). It is a direct replacement for the factory plastic turbo inlet, which sits on the suction side of the system between the airbox and the turbocharger compressor inlet. Dinan's own install document names the application as the G2x M340i/M440i LCI2, so check that your car is the 2025-onward Gen 3 B58 car before ordering: the earlier Gen 2 B58 cars use a different Dinan inlet.

What the part actually changes is the internal shape of the flow path. The factory inlet carries sound resonator features that add restriction and turbulence; Dinan removes them and enlarges and smooths the passage, which raises intake volume and flow rate over the OEM piece and makes the turbocharger audibly more present. Dinan calls it a quick bolt-on and quotes roughly one hour of labour. Dinan does not publish an inlet diameter, a layup description, or a horsepower figure for this part number, so none are claimed here.

Dinan warrants its performance products for the remainder of the vehicle manufacturer's new-car limited warranty (up to 4 years/50,000 miles) or for 2 years/unlimited miles, whichever is greater. Dinan further states that while the vehicle is still covered by the factory warranty, it covers both a defective Dinan component and any original manufacturer component directly affected by it. Dinan also states plainly that installing performance products may affect the vehicle manufacturer's new-car limited warranty.

• Fits the 2025+ BMW M340i and M440i with the Gen 3 B58 (B58TU2) engine
• Direct replacement for the OE plastic turbo inlet
• Deletes the factory sound resonator features built into the OEM inlet
• Larger internal volume and higher flow rate than the OEM inlet, per Dinan
• Carbon fiber construction in place of the failure-prone plastic original
• Bolt-on installation, approximately 1 hour labour per Dinan

Specifications

Documents: Installation Instructions (PDF)

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