BMW Z4 2019 review: 20i, 30i and M40i driven

Small, light, low-slung roadsters: this is a formula that we hope will never go out of style. With volumes shrinking in the sports car market, though, plenty of innovation is occurring to reacquaint buyers with the unique delights fo the driver-focussed open-top. That is especially true of the 2019 BMW Z4, which launched in Australia this month.

Cognisant of the significant costs of developing an all-new car in a niche segment, for the third generation of the Z4, BMW solicited a collaboration partner and found one in Toyota. The new Z4 was developed as a convertible from the ground up but a fixed-roof coupe will sit on the same platform – and that car is the new Toyota Supra.

While cross-brand collaborations will become more frequent in niche segments in future, BMW aficionados can breathe a sigh of relief: the Z4 is very much a BMW. In this instance, it is the Supra that feels like a BMW, rather than the reverse. Having grounded this review in some recent history, let’s talk about the Z4.

The new shape has some impressive credentials on paper. Though the car is a little longer, the wheelbase is shorter, placing the driver closer to the rear axle. The track is wider. The previous version’s hard top has been ditched in favour of a far lighter cloth roof, lowering the centre of gravity and making the new-gen lighter on its suspension and Michelin Pilot Super Sports tyres.

Under the long bonnet and behind the broad grille that Aussie-born designer Calvin Luk says was inspired by the Z8, the new Z4 offers three turbo petrol engines. All are seriously good, and few will need any more than the most affordable sDrive20i grade, which is entry level in name only.

The $84,900 Z4 20i is not cheap, nor is it equipped cheaply. It isn’t slow, either, with a 2.0-litre four-cylinder that produces 145kW/320Nm and is good for a 6.6sec sprint to 100km/h. There is easily enough torque to steer this rear-driver on the throttle and it sounds properly nice under load, too, with a sizzling engine note and distinct crackle as it shifts cogs in the eight-speed auto box.

Twenty grand more buys you…the same engine, but with a larger twin-scroll turbocharger that sees outputs rise to 190kW/400Nm. This cuts the sprint to 100km/h by 1.2 sec and it feels faster everywhere, though the 30i’s core character is ultimately similar to the 20i, engine-wise.

Finally, at a steep $124,900, the Z4 M40i gets a full-fat inline six making 250kW/500Nm. This is a properly expensive, properly fast little drop-top, running mid-fours to 100km/h and sounding angry in the process. The engine sounds beautiful, with the smoothly balanced tone of an inline six-cylinder mixed with extroverted overrun pops when the throttle is lifted. With the roof down, it’s symphonic.

The six-cylinder engine provides an antidote for those who are otherwise interested in a Porsche 718 Boxster or Cayman but are turned off by those vehicles switching to exclusively four-cylinder power and have been criticised for their rather ordinary engine and exhaust noise.

Though the M40i is admittedly a weapon, and a rather unique car for combination of a large engine, small size, and rear-driven nature with the driver sat atop the rear axle for maximum effect, we were more taken with the four-cylinders.

With less weight over the front axle, the 20i and 30i feel less encumbered when pointed hard into a corner. The truer and more eager front end is important in a car such as this, which needs to encourage drivers to string corners together and flatter them while doing so. Both fours do a better job of this.

We do like the steering weight but we’d love to see a faster, more direct, more aggressive steering ratio. The dartiness of a Porsche Boxster – let alone a Mazda MX-5 – is not quite present in the Z4. Ultimately, while the BMW is adequately sharp and fun to drive near the limit, the steering is too laid-back, not quite providing that mystical level of connection to the machine that the leagues-cheaper MX-5 does out of the box.

So, steering from the front end could be sharper – but thankfully, the torquey Z4 offers such a high degree of throttle steerability that we largely forget about anything else. Even the 20i is hilarious to drive, with the ability to slide the tail out in a lairy manner out of junctions or, on the other end of the sensibility scale, you can make subtle corrections to your line through corners by gently dabbing the throttle.

This effect only gets better in the 30i which increases torque by another twenty per cent – and we love the optional limited slip differential on this mid-specification car which means you can get the power down even quicker. The LSD is standard on the snorting M40i.

No complaints about the ride, either, which achieves an expert balance between firmness and supple compliance. The driver can feel what the road surface is doing through the wheel but big ruts and imperfections do not deliver the blow you automatically expect. The damping is excellent.

This is not a quiet car, even with the soft-top closed. It’s by no means raucous, but the benefits of switching back to a lighter cloth roof were going to require compromises somewhere, and road and wind noise is that compromise. Still, you get to hear the well-tuned exhaust notes, which have plenty of crackle and pops in all three variants – though the ballistic M40i is particularly special.

With the roof down you’ll want the standard seat heating and the warm air pumping, because the Z4 does not get the neck-warming air collar system that is offered with the (far more expensive) 8 Series convertible that we drove in the same week.

The interior is a compact, attractive place to spend time. The dash is very similar to that on the new 2019 3 Series, condensed for the Z4’s small size. We love the standard sports buckets with integrated headrests and classy quilted patterns, and applaud BMW for continuing to offer a range of upholstery colours other than black: you can grab red, white or tan leather, too. Plus, there’s a leather/alcantara mixed option.

While the engine spread offers a good amount of choice, Australia gets a very high standard of equipment from a global perspective – even on the ‘base’ 20i. The M Sport aesthetic package is standard rangewide, bringing with it appropriately-sized 18-inch wheels. All cars sport leather seats with heating, power adjustment and memory for both front pews.

There’s a ten-inch touchscreen with iDrive on all cars and navigation, digital radio and wireless phone charging is included. It’s just a shame BMW cheaps out with Apple CarPlay, which is standard and wireless … for the first year only. After that, you’re asked to cough up for a CarPlay subscription.

There is a more basic safety pack on the 20i that does not have full autonomous emergency braking, though lane departure warning, blind spot monitoring and rear cross-traffic alert are all appreciated. The 30i and M40i both have AEB that doesn’t just slow the car, it can stop it, too.

The $20,000 jumps up to the more powerful engines mainly bring just that: power. Over a 20i, the 30i also brings adaptive dampers to the table, plus beefier brakes, 19-inch wheels, and full keyless entry. From there, the M40i adds in an LSD (optional on the 30i), plus a Harmon-Kardon stereo, lumbar support, and differentiated 19s.

Like other BMWs, the Z4 offers upfront servicing packages and it is covered by a three year, unlimited kilometre warranty which is normal for the luxury segment but a bit short when you consider most of the market has moved to five year arrangements.

Faster, stiffer and better than any of its predecessors to drive – there is a lot to recommend about the 2019 Z4. It’s certainly expensive, which will turn some buyers away, but BMW will happily walk those people into a more affordable 2 Series convertible. As a smaller, more focussed roadster that can seat two and no more, the Z4 manages to blend a whimsical weekender vibe with brutish levels of power, in the M40i at least. That’s a recipe we quite like.