The B58 in your M340i, M440i or M240i is one of the best six cylinders BMW has ever built. The factory intake is not. It is quiet by design, tight on volume, and it hides the turbo sounds you paid for behind a resonator. Pop the hood, drop in a proper intake, and the car finally sounds like the engine inside it.
The Dinan Cold Air Intake for the BMW G20 M340i, G22 M440i and G42 M240i is a semi-open system that flows 58% more air than stock. Dinan reworked the entire lower airbox, not just the lid, and on a completely stock car it measured up to +9 WHP at 6500 RPM and +8 lb-ft at 6000 RPM. It is built from high heat deflection PEX, so it looks factory under the hood while doing a lot more work.
How the Dinan Cold Air Intake Improves Your B58
The stock box is the bottleneck. Dinan enlarged the lower airbox by 60% and fit a custom free-flowing filter with 40% more filter area than the factory element (115 in² vs 82 in²). A secondary inlet brings in extra air, and Dinan tested multiple opening shapes, sizes and locations to make sure that added air source does not raise intake temperatures. Removing the factory intake resonator is what lets you hear the turbo spool and the blow-off. You get sharper throttle response and a sportier sound without any drone-inducing open cone under the hood.
Why PEX and not carbon? Dinan calls this the best dollar-per-horsepower B58 intake in its lineup. It delivers the same performance and sound as the carbon fiber version, with an OEM look instead of a show piece.
Dinan Cold Air Intake Fitment, Tune and Legal Status
No tune is required. Dinan's gains were recorded on a completely stock car, and the intake works with or without the factory strut bracing. It fits every G2x M40i variant listed below. Before you order, know this: it is not legal for sale or use in the State of California. It is sold under the EPA Tampering Policy for other states, CARB testing is pending, and no CARB Executive Order number has been issued. Dinan part number D760-0069. Sold by AutoTecknic, an authorized Dinan dealer.
What's Included
- Dinan enlarged PEX lower airbox
- Custom free-flowing air filter
- Installation hardware
Key Features
- Dinan-tested gains on a stock car: up to +9 WHP and +8 lb-ft
- Flows 58% more air than the factory intake
- Lower airbox 60% larger than stock
- 40% more filter area: 115 in² vs 82 in² stock
- Secondary inlet tested to add air without raising intake temperatures
- High heat deflection PEX construction with an OEM look
- Resonator delete for louder turbo spool and sharper throttle response
- Works with or without factory bracing, about 1 hour to install
Vehicle Fitment
Fits the following B58-powered BMW models:
- BMW M340i / G20 Sedan (2020-2026): M340i, M340i xDrive
- BMW M440i / G22 Coupe (2021-2026): M440i, M440i xDrive
- BMW M440i / G23 Convertible (2021-2026): all M440i Convertible variants
- BMW M440i / G26 Gran Coupe (2022-2026): M440i xDrive Gran Coupe
- BMW M240i / G42 Coupe (2022-2026): all M240i variants
Not for 230i, 330i or 430i models with the four cylinder engine. Those use Dinan part D760-0070.
Installation Notes
This is a bolt-on job. Dinan rates it at about 1 hour of labor, and a DIYer with basic hand tools can handle it on a cool engine. Follow the Dinan instructions included with the kit.
- Let the engine cool and remove the engine cover as directed in the instructions.
- Disconnect the intake duct and remove the factory airbox and resonator.
- Install the Dinan lower airbox and filter in the factory location.
- Reconnect the intake duct and secure all clamps with the supplied hardware.
- Start the engine and confirm all connections are tight with no warning lights.
