BMW M340d and M440d: Why we developed our own B57R turbo inlet variant
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The B57R family is technically closely related – however, the air ducting and connections are not identical for every application. Therefore, we have developed a dedicated turbo inlet variant for the OEM version 13718596434.
Not all B57R engines are the same
BMW uses the B57 in numerous high-performance diesel models. At first glance, it might seem logical to use an existing turbo inlet design for other B57 applications as well.
However, during the development of the new variant for the M340d, M440d, 440d, and ALPINA D3 S, we conducted a detailed examination of the specific OEM version.
This revealed that the connection and geometry of the corresponding clean air pipe differ from other B57 applications.
For this reason, we have developed a distinct, vehicle-specific optimized geometry for this version.
A dedicated variant for OE 13718596434
The new RevDop turbo inlet is specifically designed for vehicles equipped with the corresponding OEM version 13718596434.
This allows us to tailor the geometry precisely to the actual application, rather than covering various B57 applications with a single geometry.
The corresponding applications include, among others:
BMW M340d xDrive
BMW M440d xDrive
BMW 440d xDrive
BMW ALPINA D3 S
The decisive factor for identification is the OEM part number.
20% more fluid volume
An essential part of our development was optimizing the available interior space.
The stock design features an integrated resonator in the interior. For the RevDop design, the geometry of this area has been completely redesigned.
As a result, the usable fluid volume has been increased by 20%.
This was not just about making the component larger. The key was to utilize the existing installation space in such a way that air is guided as efficiently as possible through the inlet to the turbocharger.
OEM vs. RevDop
The design difference is clearly visible in comparison.
In the OEM inlet, the resonator takes up part of the interior space.
The RevDop inlet utilizes this area differently, thereby creating a significantly more generous flow geometry.
OEM:
Resonator in the interior
RevDop:
Optimized interior geometry without a resonator
Result:
20% more fluid volume
Not just larger – but specifically optimized
At RevDop, we do not develop turbo inlets based on the "bigger = better" principle.
In every development, we consider factors such as:
Fluid volume
Pressure loss
Flow distribution
Airflow into the turbocharger
Installation space and connections
To do this, we combine 3D scanning, CAD design, and CFD flow simulation.
This turns the analysis of the OEM geometry into an independent, technically optimized design.
Why the exact vehicle application is crucial
Especially with modern BMW engines, the designation B57 alone is not always sufficient to uniquely identify a component.
Even if engines belong to the same family, adjacent components and their connections can differ.
That is why we increasingly work with specific OEM part numbers and vehicle-specific geometries in our developments.
This creates a clear basis for identification and prevents different applications from being treated as the same solely based on the engine designation.
Engineering instead of a universal compromise
Our goal is not to cover the largest possible number of vehicles with a single component.
Our goal is:
The right geometry for each specific application.
This is why we continue to develop existing products whenever a specific vehicle application makes a dedicated technical solution sensible.
3D scan → CAD → CFD → Prototype → Test
We don’t develop based on gut feeling. We develop based on data.
The new B57R turbo inlet
The new variant has been developed for the corresponding BMW B57R applications with the OEM part number 13718596434.
View BMW B57R turbo inlet for M340d, M440d, 440d & ALPINA D3 S →