BMW AG: Mini 1.6L Turbocharged DOHC I-4

Few engines got more raves this year than the not-so-new turbocharged “Prince” engine in the Mini Cooper hardtop.

We tested this engine for the first time in the Mini in 2007, but were not all that impressed, even though it was a huge improvement over the previous Pentagon engine, which actually made our list in 2003. More on this later.

The big difference this year is the addition of BMW AG’s excellent Valvetronic fully variable valve-timing system, which enhances power and fuel efficiency.

Combining Valvetronic with the direct-injection system and twin-scroll turbocharger of the “S” version of the Prince was a deal-clincher for Ward’s judges, combining stunning performance and superb fuel economy into a driving experience that really sells the car.

“Averaged 34 to 35 mpg (6.9 to 6.7 L/100 km) while beating it hard,” says Ward’s AutoWorld Executive Editor Tom Murphy. “Valvetronic makes a huge difference.”

“As high-tech as they come. Only thing missing is a flux capacitor,” says WardsAuto.com Associate Editor James Amend.

The turbocharged I-4 allows the Mini hardtop to sprint to 60 mph (97 km/h) in 6.6 seconds, and overboost on this improved engine pushes torque to 192 lb.-ft. (260 Nm).

The upgraded Prince also performs admirably in Mini’s larger and heavier Clubman and Countryman cross/utility vehicle.

Special Report

Ward’s 10 Best Engines

Back in 2003, the last time a Mini engine made the Ward’s 10 Best Engines list, a supercharged engine displacing just 1.6L was quite unique in the U.S.

We were impressed with the Pentagon I-4’s 102 hp/L – a spec that was outlandish at the time – and were smitten with the lovely turbine-like whine of its supercharger.

But the novelty wore off. The following year we removed the automotive beer goggles and were chagrined to see the engine was quite old-fashioned, with a cast iron block and only one camshaft for four valves per cylinder, severely limiting the flexibility of the valvetrain.

Worst of all, fuel economy averaged 26 mpg (9 L/100 km) in combined city/highway real-world driving.

Few were surprised when Mini owner BMW abandoned the Pentagon, produced in Campo Largo, Brazil, by the Tritec joint venture owned by DaimlerChrysler and BMW.

BMW builds the Prince at its Hams Hall assembly plant in Warwickshire, U.K., and designed the engine with PSA Peugeot Citroen.

It was far more advanced and efficient than the Pentagon from the get-go, but it still took a few years of significant improvements to make the Ward’s 10 Best Engines list.

Now if Mini could just figure out a way to emulate the one outstanding feature that sold us (and many Mini fans) on the old Pentagon: the wonderful whine of that supercharger.

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Ward's 10 Best Engines is a copyright of Penton Media Inc. Commercial references to the program and/or awards are prohibited without prior permission of Ward's Automotive Group.