December 17, 2008 BMW's latest addition to its roadster family is set to make its North American debut at the 2009 NAIAS in January packing more power, versatile storage options, and a host of goodies not previously seen in the range including a two-piece, electro-hydraulically operated retractable hard-top roof and adjustable drivetrain and suspension which enable the driver to choose between three different ride heights as well as different throttle and steering response set-ups and gear change times.
The three-liter, in-line 6 cylinder engine puts out 300 hp and 255 hp for the Z4 sDrive35i and isDrive30i respectively with both featuring steering wheel-mounted paddle shifters. Both models are available with a manual six-speed gearbox as standard which boasts much shorter gearshift travel than on all other current BMW models.
The extra grunt in the sDrive35i is courtesy of twin turbochargers which each supplying three cylinders, high precision injection and an all-aluminum crankcase. The 300 hp peak comes at 5,800 rpm and maximum torque is 300 lb-ft, maintained through a broad rev range from 1,400–5,000 rpm. The 35i gets to 60 mph in just 5.1 seconds - five flat with the optional seven-speed double clutch sport automatic transmission - and its top speed is limited electronically to 130 mph (150 mph with the Sport Package).
The naturally-aspirated BMW Z4 sDrive30i hits 255 hp at 6,600 rpm and has a maximum torque of 220 lb-ft which kicks in at 2,600 rpm. Top speed is electronically limited to 130 mph (150 mph when equipped with the optional 6-speed sport automatic) with acceleration slated at 0 - 60 mph in 5.6 seconds (with optional sport automatic in 6.0 seconds).
Drive is from the rear-wheel and the new Z4 rides on “double-jointed” front suspension made largely of aluminum. Adaptive M Suspension with Electronic Damping Control can vary the suspension response so quickly that the back wheels will adjust in time if the front wheel hits a bump and can be used to lower the ride height by up to 0.4 inches (10mm). Dynamic Drive Control (available on sport option) gives the driver three different control settings: NORMAL, SPORT (which provides more-direct steering and tighter gas pedal response) and SPORT+ (allowing slight wheelspin, controlled drifting... and more fun).
Activating Dynamic Traction Control is operated at the touch of a button and the driver's control options are further extended by steering power assistance which is is activated only when required or desired by the driver.
The new two-piece aluminum retractable hardtop can be raised or lowered in 20 seconds with the flick of a switch in the center console or by remote control, and as well as promising outstanding acoustic and aerodynamic qualities, the hardtop also sits higher and offers greater visibility than previous models - 40% larger side-windows and 52% better visibility at the rear. The rear window also gets an electric defroster and the four side windows of the can be lowered individually.
Storage - not usually a selling point in a car of this ilk - is designed to be flexible with a moveable partition separating the roof and luggage compartment. If the roof is closed, the partition can be folded up to increase storage space and there's also an through-loading option that caters for longer items like golf clubs. Add to this a 10-liter glove box, hinged compartments in the doors, additional space behind the seats, plus fastening nets and a storage box in the bulkhead for the "Cold Weather Package" and you' should be able to lug more than just your sunglasses.
In the cockpit there's a little more space for the occupant (headroom +0.20", shoulder room +0.79" and elbow room +1.69") and infotainment and navigation capabilities is delivered via BMW's iDrive control system which includes an 80 GB onboard hard disc (with 15 GB of this available to store music. The leather is treated with "Sun Reflective Technology" which serves to reflect infrared radiation in the sunlight and protect the seats, steering wheel and interior lining.
Other notable features include 17-inch light-alloy rims with runflat tires and a Tire Pressure Monitor, LED lighting, head/thorax airbags integrated on the outside of the seat backrests, the option of a 14 speaker, two subwoofer, 650 watt sound system and a choice of nine color tones.
Europe will see the new Z4 line-up, including a 204 hp SDrive 23i model, on the showroom floor from May 2009.View gallery - 14 images