We like
Body rigidity, performance, handling

Room for improvement
Price, steering, polarising styling

BMW Australia says Z4’s higher price positioning, its lack of a four-cylinder variant from launch and, although careful not to stress this point, its greater dynamic potential means it is not a direct replacement for the popular Z3, of which 2464 were sold in Australia since 1997.

The company does, however, concede that the hole left vacant since the original Z3 1.9-litre four-cylinder was replaced by the 2.2-litre six will eventually be filled by a possible convertible version of the 1 Series sedan.

As it stands, Z4 will line up in the premium convertible market against the $80,900 TT Roadster and $92,500 TT Roadster quattro, Honda’s $74,590 S2000, the Mercedes-Benz SLK200K ($83,074 manual, $86,174 auto), SLK230K ($93,174 manual, $96,274 auto) and the more expensive SLK320 ($112,074).

BMW also makes much of Z4’s price shortfall to Porsche’s popular Boxster 2.7 ($108,500 manual, $115,500 auto) and even the $133,100 ($115,500 auto) Boxster S 3.2 and $154,074 SLK32 AMG, but Z4’s more realistic, M-badged rival for these super-roadsters is yet to appear.

While the Sequential Manual Gearbox-equipped versions of both Z4 variants sold in Europe (also available in 3 Series coupe models there) are unlikely to be offered here, BMW admits an M version to follow the potent M Roadster is on the cards for next year. But don’t expect a replacement for the unloved Z3-based M Coupe "bread van".

The biggest restriction to Z4 sales, according to BMW Australia, will be a strictly limited supply line from the Spartanburg, US, factory where Z4 is built (along with X5). Just 400 Z4s will be delivered this year – most of which are said to be accounted for - with a further 500 due here next year.

Along with what BMW describes as a more mature market with more rivals, the worldwide Z4 supply shortfall means Z4 will not emulate the Z3’s stellar initial success, which numbered 1104 sales in its first year.

So numbers will be down, but BMW expects the same sort of customers for Z4, meaning an average age in the mid-40s with a 65 per cent split in favour of males and an initial preference to manuals that’s expected to shift towards autos.

According to BMW HQ, Z4 buyers will include enthusiastic achievers, spirited connoisseurs, self-rewarding empty-nesters and, wait for it, post-modern hedonists.

Whoever buys it, Z4 is said to "take the roadster philosophy to the next step" by building on the strengths of Z3 – the most successful European roadster ever, with 300,000 global sales – while remaining faithful to BMW’s roadster concept that dates back 66 years to drop-tops like the 328, 507 V8 and Z1.

Bigger than before and based on an exclusive new platform featuring 50/50 weight distribution, the longest wheelbase and widest track in its class, Z4 retains its classic, long-bonnet proportions and is second only to Boxster in overall length.

Some 36mm longer at 4091mm, 18mm wider 1781mm and 1299mm high, Z4 now has a 49mm longer wheelbase of 2495mm and wider tracks (now 1473mm front, 1523mm rear). Its aerodynamic drag coefficient is 0.35Cd and Z4 weighs a lightweight 1290kg (1310kg auto).

Interior space – especially head and legroom - has increased substantially thanks in part to 20mm deeper seats, while boot space with the roof open is claimed to be the most voluminous in class at 240 litres (260 litres with it closed).

The fully lined fabric roof with heated rear glass is claimed to be the world’s fastest fully automatic electric roof, opening or closing in less than 10 seconds. The new interior also features an automatic-locking, 10-litre storage compartment when satellite navigation is not optioned.

Z4 is the first BMW to employ electric power steering (similar to Mini’s, with basically unchanged rack-and-pinion hardware), and the new chassis also features different MacPherson strut front suspension and an all-new, 3 Series-based multi-link IRS to replace Z3’s dated semi-trailing arm rear system.

The inline six-cylinder 24-valve DOHC engines come to Z4 unchanged from the likes of 3 and 5 Series, meaning 141kW at 6000rpm and 245Nm of torque at 3500rpm for the 2.5i, and 170kW at 5900rpm and 300Nm at 3500rpm for the 3.0i.

That brings entry level BMW roadster power from 124 to 141kW, which translates to a 0-100km/h acceleration figure for the 2.5i of 7.0 seconds (7.5 auto, while Z3 2.2 was 8.2).

More telling, Z4 3.0 claims a 0-100 acceleration of 5.9 seconds (6.2 auto), compared to the similar-engined Z3 3.0’s 6.3. This compares with Boxster’s claimed 0-100 figure of 6.4 seconds and SLK320’s 6.9. Top speed for the 2.5i and 3.0i is 220km/h and 250km/h respectively.

Standard on all models is ABS, twin front and side airbags, Dynamic Stability Control III, Dynamic Stability Control + Traction, Corner Braking Control, Dynamic Traction Control. Significantly, there’s also Driving Dynamics Control from M5 and M3, which at the push of a button changes to more aggressive engine mapping, lower steering assistance and, in auto models, a more spirited shift pattern.

The T-shaped dash features real brushed alloy fascias, climate control air-conditioning, two cupholders and classic instruments, while all interiors also get full leather trim (including steering wheel, gearknob and handbrake) power-adjustable sports seats with driver’s memory, trip computer and CD audio. Also standard is rain sensing wipers, auto headlight control, front fog lights, twin fixed rollover hoops and run-flat tyres.

The 3.0i adds double-spoke 17-inch alloys wheels to the 2.5i package (which includes 16-inch cross-spoke alloys), plus a 10-speaker/CD stacker sound system, six-speed manual transmission, larger brakes, different grille and headlight cluster, larger exhaust and an interior light package.

Besides the choice of black, grey or beige hood fabric, options include a number of metallic paints in addition to the four standard colours ($1175), satellite-navigation ($5700), Carver Hi-Fi audio, Bluetooth mobile phone package ($1800), in-dash Mini Disc player ($350), Xenon headlights with washers ($1820), Park Distance Control ($920), 18-inch alloys and 15mm-lower M Sport suspension. A wind deflector and hard-top will also become available.

On the road, one quick drive is enough to understand, in no uncertain terms, that Z4 is different to Z3.

However, a 350km road loop over some of Queensland’s more testing back-roads – used by BMW to demonstrate to motoring journalists just how good Z4 is – is enough to convince most that Z4 is the roadster that Z3 should have been some six years ago.

The new bodyshell - which does a commendable job of modernising the classic Z3 shape without ruining its timeless roadster proportions - combines soft curves, two hard waistlines and convex and concave surfaces to produce an unmistakable on-road presence.

Just a little Boxster-esque from behind, the Z4 carries plenty of BMW roadster styling cues, combined in one of the most aggressively modern open-top shapes on the road.

In contrast, the unique new interior is minimalist, yet strikingly individual with its generous swathes of real brushed aluminium and its steering wheel and instruments echoing the complex exterior styling.

Equally apparent, however, is the extra space inside the Z4’s voluminous new cabin. With more leg, head, shoulder and elbow room – plus one of the biggest roadster boots going – Z4 makes the outgoing Z3 and rivals like the S2000 seem positively cramped.

Indeed, this is one roadster that can accommodate 180cm-plus frames, and their overnight luggage, with ease. There is a handy 10-litre storage bin between the seats (when sat-nav is not fitted) that locks automatically when the roof is down and, for the first time, there’s a single cupholder at either end of the new dash.

Other quality hallmarks are there too, like a super-quick and fully lined and insulated fabric roof that sets new benchmarks for opening efficiency. While its electric motor is noisy, Z4’s roof does a commendable job of keeping wind noise at bay and there’s a general feeling of solidity some other roadsters, including Z3, fail to match.

In fact, with an exclusive new platform boasting double the torsional rigidity of Z3 – thanks to stronger sills, widespread use of high-strength steel and a strut tower brace – Z4 exhibits a distinct lack of squeaks, rattles and scuttle shake, the windscreen-wobbling bane of many convertibles. If it doesn’t match the solid-as-rock feel of drop-tops like Boxster and SLK, then it comes pretty damn close.

Z4’s more substantial chassis feeling is backed up by the 3 Series sedan’s impressive multi-link rear suspension, which replaces Z3’s antiquated trailing arm IRS. With greater travel, better compliance, more grip – on either the 2.5’s 16-inch or the 3.0’s 17-inch Bridgestone rubber - and no more axle tramping, the Z4 rear-end compliments the stiff new chassis rather than detracting from it.

Similarly, the revised MacPherson strut front suspension is a careful development of one of Z3’s few strong points, and while it’s still biased towards well-telegraphed understeer at the limit of adhesion, the front-end geometry is unquestionably quick.

Ride quality is firm without being harsh, and there’s no getting away from the jiggly composure firm that’s inherent with all short wheelbases, but the fact both Z4s bottomed out over a number of particularly vicious road depressions did cause concern.

The other point of contention at the launch was Z4’s particularly direct steering. The first BMW model (aside from Mini) to incorporate electric steering, the Mini-derived Electric Power Steering system eschews hydraulic power assistance for an electric motor adapted to same basic rack that now.

The upshot is extremely responsive steering (and a turning circle of just 9.8 metres) that feels a little like a super-nimble 156 GTA Alfa, but with a slightly vague on-centre feel until the steering weights up either side of straight-ahead.

It proved somewhat unsuited to some of the heavily-crowned, randomly-cambered Queensland B-roads we traversed, requiring a tight grip on the steering wheel over broken surfaces and plenty of concentration at high speed. Perfectly at home on smooth roads, the new steering becomes nervous only when roads deteriorate. But it also requires adjustment even in constant-radius turns, and does lack the communication or feedback of, say, Boxster. BMW says the new EPS system saves one litre of fuel every 400km. We say this is irrelevant for most sports car owners.

But there’s very little else to fault with Z4. Except, perhaps, its abandonment of a full-size spare wheel, space saver or even the previous car’s compressor-equipped repair kit.

Instead, Z4 employs run-flat technology, with a sensor advising when a puncture occurs and the special, thick-walled tyres and high-humped rims able to proceed at 80km/h for a maximum of 150km (similar to a space-saver) before being repaired. BMW says the run-flat wheels and tyres are around the same price as conventional items, but their availability in remote areas is questionable.

Performance is another area Z4 is poles apart from Z3. While the original 1.9-litre four-cylinder Z3 (later replaced by the 2.2 six) could only be described as an under-powered hairdresser’s car, no such accusations can be levelled at the entry-level Z4 2.5i. Delivering strong urge from few revs with a fantastically raspy, metallic exhaust note (that deliberately enters the cabin via special sound chambers), the 2.5 is happy to trickle around town or be thrown against its redline.

Similarly, the 3.0i works equally well in either drive mode or by using the Steptronic auto’s sequential shift function, but it’s much more rewarding as a six-speed manual, which is tighter-gated and shorter-throw than the 2.5’s five-speed manual. Though it’s geared shorter overall, the 2.5 could use an extra ratio.

A new dimension for both cars is the addition of M3/M5’s Sport button, which noticeably increases steering weight and engine mapping aggressiveness, and gives both cars another personality altogether.

There’s no doubt both Z4’s make a far more compelling sports car argument than any Z3, including the slow selling M Roadster that was considered the weak link in BMW’s M range. Steering aside, the 3.0i in particular stacks up well against the much more expensive Boxster 2.7 and its highly involving chassis is likely to leave most other rivals in its wake.

Z4 has raised BMW’s roadster benchmark considerably by matching or bettering the best open-tops in terms of structural rigidity, handling and performance.

A lot more roadster for a little more money, this is undoubtedly the roadster Z3 should have been. With a chassis that begs for even more urge, we can’t wait for the M version.