Note: We have a more comprehensive analysis of the BMW B58 engine, click and view it:
The upcoming 2016 BMW 340i will be equipped with a 3.0L turbocharged I6 engine (code name: B58). This is not the same N55 engine which is widely used in many BMW cars at this moment (like 235i/335i/435i/535i/740i etc.), instead the B58 engine is an completely-new design and has many fundamental differences than the N55.
Below are some analysis based on the engine structure images released by BMW.
1. The biggest change in the B58 engine is its block is a closed deck design (while the N54/N55 is an open deck). A little background info: in the open deck design, the cylinder wall of each cylinder are only supported by two places from the block; an the closed deck means the cylinder wall is almost fully connected to the block, with just some engine coolant passages. Closed deck design means the engine can take a much higher turbo pressure.
This image shows the open deck block on the BMW N54 engine:
This is the closed deck design in the BMW S55 engine, which is used on the latest M3 and M4:
2. The N54/N55 engine uses forged steel cylinder sleeve, but the new B58 engine eliminates the need to use cylinder sleeves, instead it is using an alloy coating (either Alusil or twin-wire arc-sprayed coating);
3. The N54/N55 is using an air-to-air intercooler, while the B58 engine is using the air-to-liquid intercooler. Air-to-liquid intercooler is more suitable for high boost/high load applications;
4. The N54/N55 engine installs a throttle body behind the intercooler; however I do not see the throttle body is used on the B58 engine (or it is integrated into the intake manifold);
5. The turbocharger has its own dedicated electric coolant pump;
6. The engine block’s coolant pump is changed to the mechanical type (N54/N55 uses electric type);
7. Single turbocharger;
8. The VANOS chain system (including upper/lower timing chain and oil pump chain) is located in the rear of the engine, this means it will be very difficult to service the VANOS and may even need to completely move the engine out of the engine bay to work on those parts;
9. Fuel injectors are directly connected to the metal fuel rails;
The below gallery shows details of the B58 engine’s different components.