New 2.0-liter turbocharged four-cylinder offers performance of a six
Woodcliff Lake, NJ – Embargo: April 18, 2011 1:00PM
EDT… Following the announcement in February of the
return of a 4-cylinder engine to the US BMW line-up, BMW today
announced that the new 2.0-liter TwinPower Turbo 4-Cylinder will first
power the Z4 sDrive28i that will arrive in BMW Centers this fall. Like
the company’s latest TwinPower Turbo 3.0-liter turbo inline-6,
the new 2.0-liter engine will combine highpressure direct-injection
and BMW’s VALVETRONIC intake control (hence the name:
TwinPower) with a forced induction system consisting of a single
twin-scroll turbocharger. With 240 horsepower and 260 lb-ft of torque,
it offers more power and torque than BMW’s normally aspirated
3.0-liter inline-6 that it replaces in the Z4 sDrive30i.
The maximum output of 240 horsepower is achieved at 5,000 rpm,
1,500 rpm lower than in the normally-aspirated 3.0-liter inline six.
The peak torque of 260 lb-ft, comes on stream at just 1,250 rpm. Not
only is that 30% more torque than the aforementioned inline-6, it also
peaks 1,500 rpm earlier. The vigorous power comes on early and climbs
steadily all the way to redline.
The 4-cylinder engine with its all-aluminum crankcase is lighter
and more compact than a 6-cylinder engine of equivalent power. The
turbocharger is a twin-scroll system. The exhaust streams leaving the
two pairs of cylinders are kept completely separate as they flow
through the exhaust manifold and the turbocharger, taking a spiral
path to the turbine wheel. This configuration results in very low
exhaust back pressure at low engine rpm, and allows the energy of the
exhaust gas pulses to be optimally managed and translated into
powerful rotation of the turbine blades, without a delay in throttle response.
The patented BMW VALVETRONIC system with seamlessly variable
intake valve lift control dispenses with the throttle valve system
typical of conventional engines. Instead, combustion air mass is
controlled inside the engine, resulting in much faster response.
Pumping losses are kept to a minimum, making the engine more
efficient. The High Precision Injection direct-injection system
also helps to improve efficiency. Centrally positioned between
the valves, solenoid injectors with a maximum injection pressure of
200 bar (2,900 psi) precisely control the supply of fuel. The fuel is
injected very close to the spark plug, resulting in clean and
The cooling effect of the injected fuel also allows for a higher
compression ratio than might otherwise be possible. This results in
further efficiency improvements. In the Z4 sDrive28i, we expect a fuel
efficiency gain of approximately 20% over the naturally aspirated
engine it replaces when combined with the 8 speed automatic transmission.
Detailed performance and efficiency specifications will follow
at a later date, but this is clearly a new chapter in the story of BMW EfficientDynamics.