BMW Z4 sDrive 18i

The Z4 sDrive18i uses a detuned version of the engine found in the sDrive20i model and it also gets a slightly detuned equipment list when compared to that car. In fact, if you specified it back up to the level of its bigger brother, you'd end up saving only around £500 rather than the £2,100 you appear to save. Still, you might not miss the leather upholstery, automatic lights and wipers and automatic climate control of the sDrive20i and if that's the case, the price of the sDrive18i might well seem entirely reasonable. There's a 'Driving Experience Control' switch which selects between Comfort, Sport and Sport+ modes. As well as adjusting the responses of the engine and DSC stability system, the different modes also alter the shift characteristics of the automatic gearbox (if specified), and the responses of the Servotronic steering function. You also get xenon headlights, air conditioning, a heated glass rear window, a Soft Close Automatic function for the boot lid and runflat tyres with a run-flat indicator. A BMW Business radio with CD player, AUX-IN socket and six loudspeakers is also standard. Trim levels start with the entry-level car and there's also an M Sport trim, with both versions available as manual or automatic.


The BMW Z4 sDrive18i is a worthy addition to the range and one which is, in effect, an sDrive20i with the power output capped at 156bhp and which does without a few bits of interior trim in order to generate an eye-catching sticker price.

Buyers save over £2,000 in the process and the fact that the insurance grouping is a little lower will also help those who are feeling the pinch when they go to renew their annual cover. Don't let the relatively modest power output put you off.

We've had some terrible underpowered BMW entry level models down the years but this is a car that really entertains, offering a brilliant chassis balance and just enough straight line speed to acquit itself against key rivals.

If you're the type that enjoys stringing a set of corners together with finesse rather than brute force, this could well be the smartest buy in the Z4 range.


Buying the least powerful engine in a BMW range has so often been the cue for a rather miserable experience.

You'd develop tunnel vision at traffic lights when the bigger-engined version pulls up next to you, wondering quite what went wrong with your career.

You'll remember duffers from the past like the BMW 518i and the Z3 1.9, cars which articulately expressed the fact you were buying a badge rather than any pretence of the ultimate driving machine. That was then.

The BMW Z4 sDrive18i might be the model which props up BMW's roadster range and at first glance paying the best part of £30,000 for a car with a 156bhp four-cylinder engine seems a bit questionable, but this is a car that actually hangs together really well as a sensible but desirable driver's car on today's roads.

Yes, it is fun to have over 300bhp under your right boot, but all too often that becomes a liability rather than an asset.

Here's a car that makes you drive smarter rather than harder.

Driving Experience

Of course, bar room wiseacres will be only too quick to let you know that a sprint to 60mph in 7.5 seconds isn't especially fast.

While it's true that you could buy any number of sporting hatchbacks that could show this Z4 a clean pair of tailpipes for ten grand less than BMW asks for this car, this is a vehicle that is nevertheless a delight to drive.

It's rear wheel drive for a start, with impeccable chassis balance and you get a folding hard top roof so that on the rare days when our Atlantic weather systems are feeling charitable, you can drop the roof and feel agreeably epic.

This model comes as standard with a firmly-weighted, six-speed manual gearbox which you'll put to some use when you're pressing on but there's also an eight-speed auto available as an option. Unlike the 3 Series Convertible, the first car BMW made with a metal folding roof, this Z4 has managed to retain the German brand's famed 50:50 weight distribution with the roof up but ironically, it's with the roof down and the extra weight over the rear wheels that it feels most responsive.

There's virtually no body roll and in the dry at least, you rarely run out of grip.

Most owners will want to pay around a thousand extra for the Adaptive M Sport Suspension which enables you to adjust the dampers depending on the driving conditions.

Most of the time, you'll only use two settings - 'Normal' and the stiffer 'Sport' - but there is also a 'Sport+' setting which lowers the car by 10mm, firming things up still further and offering 10% more driver leeway before the stability control cuts in.

Design and Build

Most cars with metal folding roofs look a bit ungainly in their proportions, but the Z4 has a classic roadster profile with long bonnet and a pert glasshouse.

The headlights now include white LED corona rings and a white 'eyebrow' with additional chrome detailing, while in profile the side gill features chrome detailing and LED side repeater lights.

The detailing might be neat but so is the packaging.

The solid roof made the second generation Z4 185kg heavier than its fabric-topped predecessor and meant a reduction in boot space (to just 180-litres with the roof down).

Still, it's no worse than its arch-rival, Mercedes' SLK in this respect and the Z4 has the advantage of being able to boost its 310-litre roof-up capacity via an optional ski-flap in the boot.

Thus equipped, you could carry either a couple of sets of shortish skis or, more ambitiously, a couple of sets of golf clubs. Annoyingly, you have to pay over £500 extra for the 'Comfort Access' option which enables you to raise this folded roof sandwich slightly to get hold of bulky stuff you put in the boot when the roof was up but which otherwise becomes trapped there when the roof is down.

Many owners will want to avoid this problem by using the 15.5-litre interior storage area behind the seats.

Otherwise, irritations are notable by their absence, unless you count the fact that the folding roof, which electro-hydraulically raises or lowers in just 20 seconds, can only be used when stationary.

Cost of Ownership

The Z4sDrive18i scores really well on efficiency measures, as you'd expect from a modern BMW.

The combined cycle fuel economy figure stands at 41.5mpg and emissions at 159g/km.

It's only when you peruse BMW's specification sheets that you realise that these are exactly the same figures as the more powerful Drive20i model and, indeed, of the 245bhp sDrive28i, at which point suddenly a little of the shine is taken off them.

Still, it's worth considering that a broadly similarly powerful Mazda MX-5 Roadster Coupe manages just 36.2mpg and 181g/km.

Advantage Munich. All of the latest BMW Z4s come as standard with facets of BMW's award-winning EfficientDynamics programme.

Technologies that improve engine performance while enhancing economy and cutting emissions include Brake Energy Regeneration, Electric Power Steering with Servotronic, Reduced Rolling Resistance Tyres, on-demand control of the engine's ancillaries and Optimum Shift Indicator on manual transmission cars.

The BMW Z4 also adheres to a philosophy of lightweight construction with the front suspension and subframe being largely made from aluminium.

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