BMW N55 Engine For Sale
This engine was introduced in the autumn of 2009 and is derived from the 3-liter biturbo N54, from which it differs in the presence of a single turbocharger. The new engine, however, is capable of delivering performance equal to that of the unit presented in 2006. In fact, if on the one hand a turbocharger is missing, on the other hand it is possible to mount and exploit the Valvetronic device, absent in the N54, which allows a more complete management of the opening of the valves, both in timing and in lift. In addition, the only turbocharger used uses twin-scroll technology, which consists in dividing the turbine and the exhaust manifold into two zones, each destined for the exhaust flow of three of the 6 cylinders of the engine. The effect obtained is that of obtaining two exhaust waves which, upon their arrival inside the turbine, do not interfere with each other, causing losses of kinetic energy, and also avoids having gas reflux effects. during the subsequent opening of the intake valve of the same cylinder.
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N55B30 (320 hp / 235 kW)
There is a second variant of this engine, characterized by the highest output values: the maximum power reaches 320 HP between 5800 and 6000 rpm, with a maximum torque of 450 Nm almost constant between 1300 and 4500 rpm. This engine was mounted on:
BMW M135i xDrive F20 / F21 (06 / 2012-02 / 2015 );
BMW 640i F12 / F13 (01- 2011 -09/2018);
BMW 640i Gran Coupe F06 (03 / 2012-09 / 2018);
BMW 740i / 740iL F01 / F02 (06 / 2012-07 / 2015).
N55B30o0 (326 hp / 240 kW)
A further third variant delivers 326 hp of maximum power between 5800 and 6000 rpm, with maximum torque unchanged compared to the version with 6 hp less. This variant is mounted on:
BMW M135i / M135i xDrive F20 / F21 (03 / 2015-07 / 2016);
BMW M235i F22 (03- 2014 -06/2016);
BMW M235i Convertible F23 (03 / 2015-06 / 2016).
A fourth variant is that of 340 HP delivered between 5800 rpm and 6500 rpm and 450 Nm developed between 1300 rpm and 5000 rpm (while they are 430 Nm peak for the version with manual gearbox) that equips, starting from September 2013, the 335i and 435i versions equipped with the M Performance Power Kit, which is the official upgrade kit offered by BMW as an aftermarket option of its dedicated M Performance line. This kit, according to BMW, allowed an improvement of 0 “3 in acceleration from 0 to 100 km / h, all with unchanged consumption.
At the hardware level, the kit was distinguished by the replacement of the airbox with one equipped with an additional front hole to ensure a greater volume of air intake, while at the software level, in addition to a specific mapping, it involved greater responsiveness of the gas pedal, as well as a much more pronounced exhaust sound release (the so-called “exhaust bubbling” ).
It is worth describing separately the characteristics of the top variant of the N55 engines. This variant draws some of the technology from the S55 engine fitted to the BMW M4. This is the case, for example, of the pistons and main bearing shells, borrowed, while the lubrication system, of the dry sump type (unlike the other N55 engines which have a wet sump instead ), has an unprecedented system of anti- flapping to prevent the engine oil, subjected to centrifugal force during high speed curves, from triggering empty draft phenomena and compromising the reliability of the engine itself.