BMW Z4 sDrive 20i 2012 Review

Price Guide (MLRP): $76,900
Options fitted to test car (not included in above price): Automatic transmission $3500; Music interface for Smartphone $220; Navigation system Professional $4500
Crash rating: N/A
Fuel: 95 RON PULP
Claimed fuel economy (L/100km): 6.8
CO2 emissions (g/km): 159
Also consider: Audi TT 2.0 TFSI Quattro Roadster (from $81,100); Mazda MX-5 Coupe Sports (from $51,930); Mercedes-Benz SLK 200 BE ( from $82,900); Nissan 370Z Roadster (from $75,790)

How BMW must curse La Nina, the meteorological she-witch that has drowned the Australian east coast in torrential rain for the last three years. Among many other impacts (not all of them negative assuredly), all that water has done serious damage to our already poor roads. Small holes have become large, large holes have become potholes and potholes have become quarries.

That’s bad news for any car but it’s a particular problem for Germany’s most sporting luxury brand, with its penchant for run-flat tyres and limited travel, firmly-set, suspension.

You ponder such things driving the new Z4 sDrive 20i, wincing from one impact to another (you simply can’t avoid them all), fearing for the integrity of tyre, wheel, bump stops and coccyx. It’s an issue that almost sneaks up on you, as the Z4 actually rides pretty well, up to a point – that point being wheel-swallowing holes. But nor is it entirely unexpected, as other new generation BMWs, such as the latest 3 and 6 Series, have also displayed this trait.

But in the Z4 it’s even more noticeable, maybe because you are sitting so low down, slung between the axles of this shark-nosed two-seat, hard-top coupe-cabrio, staring out over a long bonnet, feeling almost like you are driving from the boot.

We are driving the Z4 because it has traded in its predecessor’s naturally-aspirated 2.5-litre inline six-cylinder engine for a 2.0-litre turbocharged four-cylinder.

The old engine made 150kW/250Nm, officially averaged 8.5L/100km and drove the rear wheels via six-speed manual or automatic transmissions. Dubbed N20, the new engine drops to 135kW (-15kW), climbs to 270Nm (+20Nm), claims 6.8L/100km (-1.7L/100km) and employs either a standard six-speed manual or the optional ($3500) eight-speed ZF auto we’re testing here. Slipping under the fuel efficient luxury car tax threshold (7.0L/100km), pricing drops just under $10,000 to $76,900, meaning the base Z4 is now cheaper than its logical Audi (TT) and Benz (SLK) opposition.

Traditionalists will lament the departure of the turbine-smooth six-cylinder; modernists will appreciate the fuel economy (we averaged a still excellent 7.5L/100km on test) and broad torque range of the turbo four-cylinder, the peak arriving at only 1250rpm.

Employing twin-scroll turbocharging, variable valve and camshaft control, and direct injection, the N20 is certainly an efficient and impressively competent unit. There’s only a slight suggestion of hesitation at very early, initial throttle inputs, otherwise it pulls very cleanly towards its 7000rpm redline.

Like the 'old' six, it’s in the upper reaches where the engine really does gain character. BMW claims a 0-100km/h time of 7.2 secs (6.9 for the manual) and that actually seems a bit conservative. Peak power kicks in at a relatively high 5000rpm, and there’s no doubt this is where the car feels at its most vital; especially if you have shifted the Dynamic Driving Control from Comfort to Sport, sharpening up throttle response and lifting the gearbox change threshold, or even Sport+, where stability control’s noose is loosened.

So give it a rev, change gears via the lickety-split paddle shifters, point it at a (smooth) winding road and away you go. The Z4 has transformed from ambling and almost forgettable to interesting and involved. The electronic power steering isn’t the most communicative or millimetre accurate, but it is quick, and there is throttle adjustability as well. It’s not blindingly fast, but is one of those cars that allow you to extract most of its potential without being in danger of calamity or prison.

Transfer to the rougher stuff and there’s bump steer from the rear and a lessening sense of control. Commendably though, even as Z4 dances a bit of a jig across the rough stuff, there’s very little obvious looseness.

Retract the aluminium roof, a process that takes 20 seconds, and your hair will be tussled at 100km/h. But it remains mostly calm within the cockpit -- even without a wind deflector.

In some ways it’s a relief to let the world in, because with the roof in-place the Z4 is a noisy little cocoon. It’s mostly tyre noise on coarse surfaces from the 17-inch 225/45 Bridgestone rubber that is the problem. The radio has to be cranked up and conversations are loud or abandoned.

Alas, the cabin isn’t something to shout about. Controls are logical enough, except for the proximity of the cruise control and high beam stalks, but here is a lot of dark, hard plastic, some brushed aluminium dressing, plenty of joins and an overall lack of occasion. The tombstone seats (with sun-resistant leather trim) are all encompassing but lacking in substantial support.

The pedal box is large but the brake pedal crowds in too much on the accelerator for my clodhopper feet.

The boot, unsurprisingly, is limited on space too. With the roof in-place there’s 310 litres available in a somewhat irregular shape while that cuts to 180 litres when the roof is folded. A ski-hatch adds some versatility. Storage in-cabin is limited.

And so is the equipment list, befitting this model’s position in the range if not necessarily its price. In addition to the gear we’ve already mentioned the Z4 gets Star-spoke alloys, Bi-Xenon headlights, dual-zone climate control, cruise control, Bluetooth, seat heating, CD, USB and aux-in, four airbags, a roll-over safety system and front and rear parking sensors. There’s no power seating, or standards at-nav.

Add it all up and the Z4 sDrive 20i is a worthy improvement from its predecessor; both cheaper and more efficient and just as much fun to drive when you give it a rip. However, the interior noise, the blandness of the cabin and the painful impact of its limited ability to cope with rugged surfaces work against it.

So for BMW and the Z4’s sake, let’s just hope La Nina lets up, the sun emerges and the potholes are patched!

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