BMW E81 E87 E90 E91 E92 Diesel N47 N57 Intake Silencer Air Filter Box 7811904

BMW E81 E87 E90 E91 E92 Diesel N47 N57 Intake Silencer Air Filter Box is an original intake system component designed for Diesel engines, ensuring stable operating conditions for the power unit. The OEM design guarantees proper airflow guidance, which promotes uniform combustion and correct operation of the auxiliary equipment. This used housing is a great choice for servicing or repairing the intake system in BMW cars of this series.

Specifications and technical data

• SKU: 7811904-1
• Mark: BMW (Genuine OE)
• Condition: Used
• OEM Part Number: 7811904
• Substitutable numbers: 13717811904, 7811904, 13717797471, 7797471
• Fuel type: Diesel
• Category: Air Filter Housings

Purpose and function in the intake system

The air filter housing in BMW E81, E87 LCI, E90, and E92 models is responsible for the airtight seating of the filter element and directing the air intake to the diesel engine. A properly selected housing:

• stabilizes airflow in the intake duct,
• limits the ingress of contaminants into the system,
• supports the maintenance of proper diesel engine operating parameters,
• ensures correct mounting of hoses and sensors working with the intake.

Thanks to its fitment for a specific BMW generation, this component allows for maintaining the factory intake geometry, which is essential for both the durability of the power unit and performance stability.

Advantages of using an original BMW housing

Using an original air filter housing in BMW cars with a Diesel engine translates into a number of practical operational benefits:

• Factory fitment – maintaining the correct position relative to the intake manifold, hoses, and body mounts.
• Appropriate structural rigidity – reduction of vibrations and unwanted deformations during engine operation.
• Compatibility with the stock filtration system – no modifications required when replacing the air filter element.
• Consistency with the factory engine bay architecture – easier service access to adjacent components.

Choosing such a component is particularly beneficial for post-collision repairs, replacing a damaged housing, or restoring a vehicle to a configuration close to factory specifications.

Assembly and operational characteristics

The air filter housing from this model group has been designed with diesel engines in mind, which means it is adapted to the specific airflow requirements of diesel units. In practice, this translates into:

• manufacturer-intended mounting points to the body and adjacent components,
• maintaining proper tightness of connections with intake ducts,
• the ability to use stock brackets and clamps,
• easier diagnostics of potential leaks in the intake system.

A used component allows for economical repair while maintaining the original design of the intake system, which is important for the long-term, stable operation of the engine.

Selecting the right housing for a specific vehicle

To properly select an air filter housing for a specific BMW, it is worth paying attention to the manufacturer's markings and available interchangeable numbers – this allows for confirming compatibility with a given body and engine version. In case of doubt, it is helpful to compare the shape and arrangement of the mounts with the component factory-installed in the vehicle. This minimizes the risk of assembly problems and leaks in the intake system.

If you are planning a comprehensive repair or upgrade of the engine area in your BMW and need other components from the same group, such as intake ducts, air hoses, or additional mounting elements, check out the available parts in the BMW Air Filter Housings category.

Additional information and inspiration

For projects related to improving engine performance or intake modifications, it is worth familiarizing yourself with practical tips on using components from dismantling. Sensibly combining OEM parts with appropriately selected modifications allows for achieving a clear improvement in driving characteristics at controlled costs. You can find more on the use of used components in tuning projects in the article Emotions and design – visual and mechanical tuning of a Seat using components from dismantling.