The camouflaged sporty two-seat roadster was shown doing its laps at the BMW test centre in Miramas.
The third-generation G29 Z4 is being jointly developed with the new Toyota Supra to cut costs, so both sports cars will share components. The new Z4 will only be available with a motorised soft-top unlike the second generation which uses a retractable hardtop.
Tests are under way to tweak the Z4 performance in terms of agile handling, spontaneity and precision when changing direction and accelerating out of bends – without compromising comfort.
Trials at the Autodrome de Miramas are focusing on fine-tuning of all drive and suspension systems – the basis for the sporty driving experience offered by the new Z4.
The Z4 will come in 4- and 6-cylinder engine variants, with the sportiest being the Z4 M40i. It will get a new, more powerful in-line 6-cylinder engine, a lowered sports suspension with electronically controlled dampers, a newly developed front axle, M light alloy wheels with mixed tyres, an M sports brake system and an electronically controlled lock in the rear axle differential.
"The vehicle concept of the new Z4 is geared consistently towards agility and driving dynamics," said Jos van As, Head of Application Suspension. "The high level of body stiffness and the very rigid suspension attachment provide the basis for a set-up that guarantees the performance qualities of a genuine sports car in terms of steering precision as well as longitudinal and transverse acceleration."
Like the Nürburgring-Nordschleife, the Miramas test centre offers conditions for the new Z4 to demonstrate its driving dynamics potential. Used by BMW to develop and test new models for more than 30 years, the centre comprises a long asphalt oval and a motorway ring road for high-speed tests as well as slalom, serpentine and circular tracks and a number of handling courses and circuits featuring highly diverse types of surface.
These are currently being used for detailed analysis and optimisation of the roadster's acceleration, steering and brake response. For example, the final form of the adaptive M suspension as it interacts with the rear axle limited-slip differential is developed on the circuit that is also used for testing purposes by BMW Motorsport.
