The last time BMW offered a four-cylinder model in America was more than a decade ago. It wouldn’t make sense for their luxurious US models to be powered by a small engines, so they just offered six and eight cylinder engines. Now though the economy and environmental concerns dictates to bring back the four-bangers.
The good news is, new BMW four-cylinder engine is nothing like the old ones. It’s boosted with two turbochargers and is very similar to the firm’s renowned straight-six twin-scroll system. Only it has a displacement of 2.0 liter which makes it lighter on fuel. It is still pretty powerful at 240 hp and 260 lb-ft of torque.
The four-cylinder engine with its all-aluminum crankcase is lighter and more compact than a six-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.
It also features BMW VALVETRONIC and High Precision Injection direct-injection system, all for the sake of better efficiency. BMW will offer this unit on a wide range of cars. All these efforts have one goal in mind and that’s to arrive at the best compromise between low fuel consumption and decent performance, but as it’s always the case, it’s the performance front that suffers the most! They might promise big figures but an eco-tuned engine never delivers like a normal one.