Munich. Long bonnet, short overhangs, low centre of
gravity, soft top: the sporty two-seater doing its laps at the BMW
test centre in Miramas in the south of France is instantly
recognisable as a purebred roadster. The new BMW Z4 is currently
undergoing another particularly important stage of the process towards
serial production maturity, in this case involving driving dynamics
testing of a heavily disguised prototype. This will provide key
insights into the performance properties of the new model, whose
genuine roadster characteristics, pure driving pleasure and
captivating sporty flair will soon go out on public roads.
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 BMW Z4. The most intense form of new
dynamic roadster performance is embodied by the BMW Z4 M40i. A new,
extremely 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 create an overall package that sees the BMW M Performance
model setting a whole new benchmark for driving pleasure in the
roadster segment.
“The vehicle concept of the new BMW Z4 is geared consistently
towards agility and driving dynamics,” explains Jos van As, Head
of Application Suspension. “The high level of body stiffness and
the very rigid suspension attachment provide the perfect 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
perfect conditions for the new BMW 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 a circuit that is also used
for testing purposes by BMW Motorsport.
This intense testing process already indicates that the new version
of the roadster concept will offer a tangible increase in sporty flair
in the new BMW Z4. The new generation will particularly introduce
effective enhancements in terms of agile handling, spontaneity and
precision when changing direction and accelerating in dynamic style
out of bends – without losing out in the comfort disciplines.