BMW
S55
Production period:	since 2014
Manufacturer:	BMW
displacement:	2979 cm 3
Fuel supply:	injection
Engine charging:	turbocharger
Power:	317-368 kW
torque:	550-600 N · m

The S55 is an inline six-cylinder engine with twin-turbo charging from the car manufacturer BMW , which builds on the BMW N55 . The Biturbo was mid-2014 in the new BMW M3 (F80) and BMW M4 (F82) introduced. With the end of the last generation of the BMW M3 (E90) , the chapter on high-performance intake engine at BMW was closed. This predecessor M3 had a 309 kW (420 hp) high-speed V8 engine with four liters displacement ( BMW S65 ).

The new six-cylinder is superior to it in torque and in non-full-load situations in consumption; In normal road traffic two to three liters less fuel to be consumed.

The S55 has the same dimensions of bore and stroke and an aluminum crankcase as the N55; however, the latter is designed in a closed-deck construction in order to achieve a higher rigidity and to be able to work with higher combustion pressures; unlike its basic model he has in addition to the two turbochargers a water intercooler mounted on the motor on top.

In addition to the crankcase made of aluminum, the following three features of the weight saving serve: Instead of inserts, the cylinder liners are sprayed with electric arc ; also the cylinder head is made of aluminum; Magnesium is used for the oil sump .  The crankshaft is made of steel, forged and hardened. The final speed is 7600 min ^-1 .

The two overhead camshafts are controlled by VANOS , which now allows faster adjustments, the valves through the Valvetronic III.As with the N55, the exhaust valves are sodium-filled. 

In the most powerful version with 368 kW (500 hp) in the BMW M4 GTS (2015) water injection is used. 

Since 2016, the BMW M3 (F80) and BMW M4 (F82) with the additional Competition package is available, which raises the performance of the S55 to 331 kW (450 hp).

Also available since September 2018 BMW M2 "Competition" Coupe is equipped with the S55 engine. Here it delivers 302 kW (405 hp) and delivers a maximum torque of 550 Nm (406 lbf · ft). BMW also uses the S55 to be able to comply with stricter emission limits with the M2. 

Technical Data