Compared to the last production Z4, the Concept Z4 represents a dramatic design shift. Not only for the compact roadster, but for the BMW brand in general with omnipresent design touches like a vertically-slatted kidney grille and horizontally-oriented headlights binned in favour of newer, fresher design motifs.
Beneath the sleek new exterior the Z4 has been co-engineered with the as-yet unseen revived Toyota Supra, with the two models sharing their chassis architecture, suspension, and driveline, but with different styling and a coupe-only bodystyle expected for the Supra to help separate it from the Z4.
The production Z4 itself is still some way off being unveiled, with a 2018 Geneva Motor Show debut planned for March next year and Australian sales expected to follow in the second half of 2018.
As is so often the case, the more dramatic elements of the concept are expected to be dialled back slightly on the showroom-bound version, meaning practical touches like larger mirrors and door handles will take the place of the slick concept items. Despite this, the concept is claimed to be very close to the production version.
“It expresses the new BMW design language from all perspective and in all details,” BMW Group Senior Vice President of Design, Adrian van Hooydonk,said. “From the dynamic looking front to the striking flanks to the clean cut tail: a few lines and the subtle interplay between surfaces are enough to generate a sense of power.”
Alongside the outgoing Z4 the Concept Z4 features a longer wheelbase and wider tracks, making the new model larger and creating a more imposing stance. Van Hooydonk says the change in proportions was a result of creating a more focussed look for the car.
“A shorter bonnet and crisp overhangs ensure the driver sits closer to the centre of the car than in previous BMW roadsters,” he said. “The outline of the car follows a distinct wedge shape.”
BMW will also seek to push the new-generation Z4 further upmarket inline with its increased size, however despite persistent rumours a change of name to Z5 was not on the cards for the new model with BMW using only even numbers for its so-called lifestyle models.
“We would have had to call it the Z6. And while there has been a move up-market, it’s not quite big enough to warrant that name. In the end, we settled on the retaining the Z4 name,” a BMW source told TMR.
The fresh-faced Z4 takes its design inspiration, in part, from early BMW roadsters including the iconic 328 Mille Miglia (which was itself the subject of a Hommage concept in 2011 at Italy’s Concorso d'Eleganza Villa d'Este), with van Hooydonk referencing that car’s functional use of the material.
Another stand-out element is the use of vertically-stacked headlamps framing the Concept Z4’s face and giving the roadster a more aggressive look than the traditional horizontally-oriented face worn by the rest of BMW’s range. Despite a shorter bonnet, length is accentuated via a pair of longitudinal vents and the Z-hallmark clamshell bonnet design is retained.
Like the larger Concept 8 Series that came before it the Z4 features a deep vent behind each front wheel that creates a rising feature line through the body before wrapping into the top of the tail-lights for a noticeable wedge shape. The same forward leaning grille surface from the 8 Series concept has also been incorporated.
Other concept-special design touches that are likely to change as the Z4 marches towards production include the frameless windscreen and speedster style rear deck, to be replaced with traditional reinforced A-pillars and a pair of conventional roll hoops to boost occupant protection in the event of a rollover.
BMW is yet to reveal official detail of the roadster’s roof, although it is expected that the 2018 Z4 will return to a traditional folding fabric top in place of the hard top used on the current generation car, saving both weight and space as a result.
Inside the roadster concept, BMW has liberally applied brush aluminium and carbon fibre, some of which is expected to make way for more traditional materials in the production car, but the concept’s digital instrument cluster and head up display are expected to stay.
Thanks to the new Z4’s larger footprint, interior accommodation is said to have improved, and boot space should expand beyond the 310 litre top-up maximum of the outgoing second-generation Z4.
Beneath the slick new surface treatment the Z4 will be underpinned by BMW’s CLAR (cluster architecture) platform, already in production beneath the current 5 Series and 7 Series and set to be used under the 8 Series and next-generation 3 Series.
The multi-material structure makes use of a combination of high-strength steel, aluminium and magnesium and although official details are yet to be announced a target weight of just under 1400kg is tipped for the new model.
From launch, the Z4 is expected to come with a pair of 2.0-litre turbocharged four-cylinder petrol engines producing 135kW in the Z4 sDrive20i and 185kW in the Z4 sDrive30i. A more performance-skewed Z4 M40i is also on the cards powered by the latest incarnation of BMW’s B58 turbocharged 3.0-litre inline six-cylinder engine rumoured to develop the same 265kW as it does in the X4 M40i with all three featuring rear wheel drive dynamics.
A flagship Z4 M, powered by the same 317kW twin-turbocharged 3.0-litre inline six-cylinder engine as the M3 and M4 has also been mooted, though it is yet to be officially confirmed by the German car maker.
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