BMW Z4 comes up short on looks but soars with its six-cylinder

BMW’s Z4 was a hit as a concept. The production roadster doesn’t have the same visual impact but one key ingredient makes it an absolute winner.

Style is core to the appeal of a convertible sports car. So the responsibility shouldered by Sydney’s Calvin Luk was enormous when designing the third-generation of BMW’s Z4 roadster.

Originally shown in concept form at the exclusive Pebble Beach classic car show last year, Luk’s first draft won favour with its long wheelbase, cropped windscreen, stretched bonnet and short overhangs, taken from the textbook of how to make a beautiful roadster.

But the production version now on sale lacks the same impact.

There are good reasons. Its shorter wheelbase brings improved agility, taller customers need the wind protection provided by deeper glass and increasingly stringent crash test requirements for pedestrian protection compromise front-end styling.

BMW Z4 M40i: The six-cylinder is the pick, clocking 4.5 secs for the 0-100km/h sprint

Looks apart, those who fall for its charms can choose from three versions of the Z4, a pair of four-cylinders in the sDrive 20i and 30i plus a six-cylinder hero variant in the M40i.

Priced from $84,900, the basic Z4 comes with 18-inch alloys, sports suspension and an eight-speed automatic transmission for its 2.0-litre turbo (145kW/320Nm). You get dual-zone climate control, 10-speaker audio, BMW’s latest digital dashboard with a year’s subscription to Apple CarPlay, wireless smartphone charging and head-up display.

Z4 cockpit: Roomier, with paddle-shifters, clever digital kit and knobs for audio and aircon

The cabin is more liveable than before, with improved seat space, extra storage and a digital dash layout that is genuinely clever yet retains knobs to adjust the audio and climate control.

You can subscribe to digital services that allow some smartphones to serve as keys — even granting temporary access to friends and family. Mid-spec 30i models on sale from $104,900 get 19-inch wheels, adaptive suspension, LED headlights, active cruise control and bigger brakes to rein in the 190kW/400Nm outputs.

At the top of the pile, the main feature of the $124,900 M40i is its 3.0-litre six-cylinder turbo (250kW/500Nm), enhanced by a sports differential, 12-speaker audio, ambient lighting and further fine-tuning.

Z4: Eight-speed auto is sole transmission. M40i at $125K adds aural excitement

As ever, BMW’s inline six is a magnificent creation. Smooth and sonorous, the engine soars throughout its rev range with flexible wallop that makes it a joy to drive.

BMW reckons it’s good for a 0-100km/h sprint in 4.5 seconds, more than two full seconds faster than the base version.

Engineers tuned the machine at Germany’s Nurburgring circuit, where the M40i is quicker than BMW’s M2 performance coupe.

The big six has a fine partner in the eight-speed automatic with driver-adjustable modes and paddle-shifters, along with a carefully programmed “whomp” from the tailpipes as you accelerate through the gears.

Less impressive are the four-cylinders, which bring fake sound effects and the potential to be embarrassed by hot hatches.

The Z4 has weighty if numb steering and rear-drive playfulness but these are compromised by overly stiff suspension that even in its plushest settings never feels settled on broken roads.

Lacking the finessed composure of well-sorted performance cars such as Porsche’s 718 Boxster — or, again, some hot hatches — the Z4 can feel brittle or bouncy on the road. Of the trio, the M40i is the most convincing, whether driven hard or at a cruise. It’s properly quick and more engaging than before.

After all, if a sports car doesn’t look stunning, it should at least be fast and fun to drive.

Verdict 3.5/5

2019 BMW Z4 M40i

Sportier to drive than before and genuinely rapid in M40i trim, the Z4 brings tech appeal that rivals can’t match. It will let enthusiasts down with its ordinary looks and four-cylinder engines — and there is the promise of a sharper drive for less money in Toyota’s Supra coupe.

What’s new

2019 BMW Z4 M40i

Price: Up by $5000 or so for the six-cylinder model aimed at enthusiasts.

Tech: Modern driver aids join a digital dash, widescreen infotainment and the ability to use some Samsung phones as car keys.

Performance: Manual and dual-clutch transmissions replaced by an eight-speed auto. Six-cylinder M40i has the same 250kW as before, bolstered by an extra 50Nm of torque.

Driving: Shorter wheelbase and new front suspension make it sportier, if not as dynamic as Porsche’s benchmark Boxster.

Design: Soft roof replaces folding hardtop of the previous generation. Styling, inspired by the not-for-Australia Z8 of 2000, may be lost on local buyers.

BMW Z4

Price: $85,900-$124,900 plus on-roads

Warranty/servicing: 3 years, $1565 for 5 years

Engines: 2.0-litre 4-cyl turbo, 145kW/320Nm and 190kW/400Nm; 3.0-litre 6-cyl turbo, 250kW/500Nm

Safety: Not rated, 6 airbags, AEB, active cruise, lane keep assist

Thirst: 6.5L-7.4L/100km

Spare: Inflation kit

Supra hero

Normally regarded as a rival for Porsche’s Boxster and Audi’s TT, the Z4 faces a new threat from the Toyota Supra developed in tandem with the roadster. Available only as a coupe and at what should be a much more palatable price, the Supra employs the same core chassis and 250kW/500Nm turbo as the range-topping Z4.