The BMW Z4 is the first to come with a two-piece, electro-hydraulically operated Retractable Hard-Top roof that can be raised or lowered in 20 seconds. The new roadster is also the first vehicle to be offered with Adaptive M Suspension. Electronically controlled dampers offer three different configurations and lower the ride height by up to 10 mm for a more dynamic drive. By way of comparison, the Sport+ setting of the new car is comparable to the outgoing Z4's standard ride comfort level.
The standard Drive Dynamic Control function is another first and allows the driver to alter, depending on model specification, the throttle and steering response, level of ride comfort, Dynamic Stability Control response and, on automatic or Double Clutch Transmission cars, gear change times.
Powering the new BMW Z4 is a choice of three six-cylinder powerplants. The range flagship is the current International Engine of the Year-winning 3.0-litre twin-turbocharged engine. Producing 306 hp at 5,800 rpm, the BMW Z4 sDrive35i powers its way from zero to 62mph in 5.2 seconds (5.1 seconds for a Double Clutch Transmission-equipped car) and on to an electronically-limited top speed of 155mph. The twin-turbocharged 2,979cc engine with high-precision direct injection technology produces 400 Nm of torque from just 1,300 rpm for effortless in-gear acceleration. The Z4 sDrive35i records a combined consumption figure of 30.1 mpg (31.4 mpg) and CO2 emissions of 219g/km (210g/km).
Joining this model in the launch line-up are the Z4 sDrive 23i and the Z4 sDrive 30i. Both use the same magnesium aluminium alloy engine with Double Vanos and Valvetronic technology, but with varying capacities. The 2,497cc entry-level Z4 sDrive23i produces 204 hp at 6,400 rpm and 250 Nm of torque from 2,750 rpm. This equates to a zero to 62mph time of 6.6 seconds (7.3 seconds for the Sport Automatic) and a top speed of 151mph (149mph). In contrast the Z4 sDrive23i is capable of 33.2 mpg (34.4 mpg) on the combined cycle and CO2 emissions of 199 g/km (192 g/km) respectively. All three six-cylinder powerplants surpass the latest EU5 emissions standards.
The BMW Z4 sDrive 30i comes with a 2,996cc powerplant offering 258 hp at 6,600 rpm and 310 Nm of torque from 2,600 rpm. The six-cylinder engine records a zero to 62mph time of 5.8 seconds (6.1 seconds for the Sports Automatic) and an electronically-limited top speed of 155mph. Like the Z4 sDrive23i, the Z4 sDrive30i posts combined consumption and CO2 emissions figures, recording 33.2 mpg (34.0 mpg) and 199g/km (195 g/km).
Transmitting the power to the road in all three Z4s is a six-speed manual gearbox as standard. Customers of the Z4 sDrive23i and the Z4 sDrive30i who prefer the characteristics of an automatic can specify a six-speed Sport Automatic transmission featuring gear change paddles on the steering wheel. Buyers of the Z4 sDrive35i can choose the more advanced seven-speed Double Clutch Transmission, again with gear shift paddles located on the steering wheel.
All of the latest BMW Z4s come as standard with facets of BMW's award-winning EfficientDynamics programme. Technologies that improve engine performance while enhancing economy and cutting emissions include Brake Energy Regeneration, Electric Power Steering with Servotronic, Reduced Rolling Resistance Tyres, on-demand control of the engine's ancillaries and Optimum Shift Indicator on manual transmission cars. The BMW Z4 also adheres to a philosophy of lightweight construction with the front suspension and subframe being largely made from aluminium.
The new BMW Z4 is larger than its predecessor measuring 148 mm longer at 4,239 mm and 9mm wider at 1,790 mm, and this results in greater interior space and luggage capacity. With the roof up, headroom has been increased by 44 mm while the greater car width and design enhancements have led to 20 mm more shoulder room and 43 mm more elbow room.
For the first time on a BMW Z4 there is a bespoke storage facility located behind the driver and passenger seats. This approximate 15.5-litre single compartment stretches the width of the car's interior and features netting to hold the contents in place. It can be complemented by an optional Storage Package that adds further stowage capacity. BMW's latest generation of iDrive makes its first appearance on a Z4. The BMW Professional Multimedia Navigation system features a hard disc drive capable of 12Gb of audio file storage and BMW ConnectedDrive functionality. The system also comes with eight programmable Favourite buttons as system shortcuts.
The roof construction of the BMW Z4 creates a boot that varies in capacity from 180 to 310 litres – large enough to stow a full set of golf clubs. For the first time on a BMW Z4 customers can specify a through-loading system for additional storage capability. A hatch between the two seats permits a second full set of golf clubs to be carried.
Driver visibility in the BMW Z4 has also been improved. All round visibility is up by 14 per cent while, courtesy of the four electric windows creating a larger glasshouse, side visibility is up 40 per cent. The Retractable Hard-Top roof features a glass rear window and this too improves visibility by 52 per cent.
Prices for the new BMW Z4 will be announced in 2009.