BMW Z4

BMW Z4 (sDrive30i, sDrive35i)

BMW launched a redesigned version of its Z4 Roadster at the 2009 North American International Auto Show in Detroit. The new model represents the first complete redesign since the Z4 badge was introduced in 2002. The new Z4 is offered in sDrive30i and sDrive35i guise, mirroring the powertrains used in the automaker's 3-Series range. In addition to a new 3.0-liter engine, the new Z4 boasts a number of mechanical improvements, including the option of a seven-speed dual-clutch gearbox.

Featuring a folding two-piece aluminum roof, the car takes some inspiration from the BMW Z8's elongated profile. The new 7-Series' front face is also evident, as are 6-Series-inspired taillights.

Most attention has been paid to the Z4's exterior -- and with good reason. Many of the polarizing features of the previous Z4's design have been toned-down, amounting to a much more elegant look. BMW's radical design revolution hasn't always been aesthetically successful, at least in the eyes of the BMW faithful. But BMW styling now seems to be hitting its stride, recapturing some of its former pleasing proportions. It appears that the steady hand of BMW designer Adrian van Hooydonk is getting the beloved Bimmers back where they need to be.

The new interior is more visually pleasing, and includes a slew of comfort and usability improvements. Notably, the traditional hand brake is gone in favor of an electronic setup. BMW's latest automatic gearshift is present, and iDrive is available for the first time in a Z4. The system is built around an 8.8-inch LCD screen, featuring a 1280 x 480 pixel resolution, and an 80GB hard drive, with up to 15GB of music storage. A 650-watt 14-speaker sound system rounds out the list of high-tech features.

The new BMW Z4 is offered with the choice of two inline-6 engines displacing 3.0 liters. The engine in the sDrive30i develops maximum output of 255 horsepower from 3.0 liters capacity at an engine speed of 6,600 rpm. Maximum torque of 220 pound-feet comes at just 2,600 rpm. The car accelerates from a standstill to 60 mph in 5.6 seconds.

The more powerful twin-turbo sDrive35i has a maximum output of 300 horsepower, arriving at 5,800 rpm. The engine achieves peak torque of 300 pound-feet throughout a broad rev range from 1,400 to 5,000 rpm. The sprint to 60 mph takes just 5.0 seconds.

BMW says the motor is the first inline-six to come with twin turbochargers, High Precision Injection, and an all-aluminum crankcase. Weighing just 355 pounds, the motor owes its light weight to its composite magnesium/aluminum crankcase, cylinder head cover made of a special synthetic material and lightweight camshafts with aluminum VANOS control unit.

Top speed is electronically limited to 130 mph (150 mph when equipped with the optional Sport Package).

While both models are available with a manual six-speed gearbox, the Z4 sDrive35i is also available with a dual-clutch automated transmission featuring seven gears. A six-speed sport automatic is available on the Z4 sDrive30i. Both the automatic and the dual-clutch transmissions feature steering wheel-mounted paddle shifters.

Disappearing in just 20 seconds, the Z4's new roof promises better temperature and noise insulation than its canvas predecessor. It also boasts increased visibility and aesthetics.

Compared with the former model, the side windows are 40 percent larger, the see-through area in the rear window 52 percent larger, and all-round visibility increased 14 percent over the previous generation.