The current BMW Z4, introduced for the 2009 model year, is the second generation of the Z4 name and is as much a completely new car from its predecessor as it is reasonably possible to be. It continues into 2010 with essentially no changes.
The Z4 sports a retractable hardtop, a departure from any previous two-seat BMW. The retractable hardtop replaces the roadster and coupe versions of previous-generation (pre-2009) Z4 models with one car. The hardtop retracts for the same open-air driving of a convertible, but closes with the press of a button to provide the advantages of better security, rigidity, rearward visibility, interior quiet and the weather control of a coupe.
The Z4 offers the driving character you expect from BMW and it will be familiar to any fan of the brand. As with other cars getting bigger and laden with more luxury and features, the higher-optioned Z4s tend to feel more like grand touring machines than sports cars. In terms of a pure sports car, we liked the base Z4 sDrive30i with the optional Sport Package. The performance and feel of balanced precision is there in every Z4. The higher-performance Z4 sDrive35i with the dual-clutch gearbox gets close to the previous M Roadster as a track-day tool.
While some will choose a Z4 based solely on the badge and others solely on style, over time they will learn the real reasons, both objective and emotional, behind the car and why they want to keep it. Others will appreciate the performance and technology without regard to style, and yet others will shop merely because they've been waiting for a folding hardtop roadster from Munich.
BMW accurately points out that the Z4 sDrive35i is about the same size and offers performance close to the earlier Z8, and it does so for about half the price. The Z4 is also far more practical.
For 2010 the Z4 is offered in two models, the sDrive30i and sDrive35i. In current BMW nomenclature, sDrive refers to rear-wheel drive. However, there are no xDrive (all-wheel-drive) Z4s and no M model has been announced. Yet.
Due later in the spring of 2010, as a 2011 model, is the Z4 sDrive35is, which will deliver even more performance than the already-quick sDrive35i. It will also have enhanced aerodynamic and handling features, unique wheels, distinctive exterior appearance trim and details, and interior comfort and feature upgrades.
Classic roadster proportions give the Z4 a long hood and short decklid, shoulders over the wheel arches and tapers in three axes. The creases begun at the inner edge of the headlight housings, roll over the front fenders and lead back to bisect the door handles, while opposite lower sweeps started at the front bumper curve upward to the rear wheels.
In side view it looks like a French curve over each wheel, the forward one twice the length of the rear, and from the driver's perch the hood seems to rise from the windshield base before falling off forward. We think it looks better with the top down but it's still relatively sleek top-up and has a similar closed profile to the big Mercedes SLR. Gills behind the front wheels carry the substantial badges and the side signal repeaters are now behind opaque panels in the gills; the BMW propeller logo is still here, but no longer serves to disguise the signal.
A variety of wheel sizes and finishes are offered, and while the Z4 is light and well-suspended enough that even 19-inch wheels can deliver decent ride quality, they might not work well with poor infrastructure (rough roads), and some wheel styles will require more cleaning effort.
From dead-on at either end the top-dropped Z4 has strong resemblance to a scaled-down version of the 6 Series and its roadster precursor, the Z8. Sections of the taillights look like horizontal light tubes and appear to ramp up like theater lights when the lights are switched on. Adaptive brake lights deliver more red light when you hit the brake pedal hard than when merely slowing mildly. The center brake light is midway between the rear window and the tail on the trunk lid where it will not interfere with rear vision but will be covered up by an inch of snow. A single side twin-exhaust outlet signals a 30i, while the 35i uses a single outlet on each side, a la Z8.
Although front-end shaping is the same, with BMW's trademark corona (programmable) daytime running lights for instant identification, trim varies by model. The 30i has black vanes in its grille and a silver slash across the outer lower grilles, while the 35i has matte silver grille vanes and perimeter frames for the outer grilles. While the Z4 is close to the ground the front overhang is shorter than many other sports cars and not prone to scraping at every speed bump or mild driveway entrance.
The Z4 is longer than the Audi TT and Mercedes-Benz SLK, shorter than the Porsche Boxster, but the difference is a few inches. In height and width, they are much closer, so exterior dimensions should not factor into purchase decisions.
The Z4 is now built in Regensburg, Germany. In BMW fashion, many systems on the Z4 have been proven in other recent BMW models, including the higher-output engine, transmissions, and suspension design.
The Z4 cabin is immediately familiar to any BMW owner, with many of the Munich builder's hallmarks: Simple white-on-black analog instrumentation, sweeping driver-centric lines, functional controls, and a high level of fit and finish (apart from the molding seams on the map pockets). In a generally evolutionary upgrade you notice first that, yes, it's definitely a BMW roadster, second, that iDrive has been revamped and the parking brake lever is gone, and lastly, it feels just like the old coupe with the top up.
The Z4 30i comes with leatherette upholstery, but that is available only in black, which might not be best in sunny areas where you're likely to park the car open. Order leather (designed for a convertible climate), or get the 35i, and the palette increases to four colors and only one of them is dark; on 35i versions you can even extend the leather coverage for the ultimate in premium feel. The low-gloss brushed aluminum or ash wood trim (which does reflect a bit of glare with the top down) of the 35i may be added to the 30i.
There is plenty of space for two people in the Z4, the head and legroom being about what you find in a full-size SUV. Standard manual seats and tilt/telescoping steering column provide enough adjustment to suit many driver sizes; slender types will appreciate the side bolsters on the seats and larger bodies will be framed as much by the door and console. While they may not look like thick armchairs the seats offer excellent support over multi-hour drives; the sport seats are a bit more confining for those of wider girths yet superb for a spirited drive. The driver's footwell is large enough for size-13 shoes to comfortably operate three well-positioned pedals and there's a good dead pedal to rest or brace your left foot on.
Inside storage has long been the bane of roadsters so particular attention was paid to that. The door pocket walls tilt out for access, and in doing so make excellent coin catchers for the change flying out your pants pocket at the first hard bend. A bin ahead of the shifter has good containment properties and there's a cubby atop the dash on cars without navigation. Other storage areas are behind the seats, and there is a pass-through door available for carrying skis or golf clubs. The armrest lid conceals two cupholders, the lid stays up on its own and clears even lanky elbows, and a third cupholder clips in to the right side of the console right about where the passenger's left knee rests. Cupholders are not the priority here, driving is.
The multifunction steering wheel is thick enough to feel good and thin enough to receive all the feedback the suspension delivers. Ahead of it are a large speedometer and tach, with smaller fuel and oil temperature gauges (more useful than coolant temperature) in the bottom. Digital displays in the center handle outside temperature, mileage, trip data, and, on automatics, gear indication.
Outward visibility is good, and a major improvement with the top up. The windshield curves across the top and the pillars are no impediment, but taller drivers will have to look around the inside mirror on up-and-down winding mountain roads. The three-quarter view right behind the seats is much better because the folding top design includes two small windows. Even the 8.8-inch stowable navigation display (1280x480p) was easy to read in direct sunlight, polarized sunglasses or not.
Climate control is manual on the 30i and automatic dual-zone on the 35i with an automatic recirculation mode that senses air contaminants. With the heated seats and steering wheel option the close-the-top temperature goes down 10 degrees or more. Slide the control wheel at the center dash vents from warm to cool and the response is immediate. This happens with most of the controls. There is no need to hold the trip odo button to reset it, and some controls are designed as multifunctional with one result from a quick tap and another from depressing and holding.
Audio options include HD radio, satellite radio, glovebox-mounted six-disc DVD changer, iPod and USB ports and a hi-fi system with 14 speakers driven by an amplifier capable of delivering 650 watts. On navigation-equipped cars much of the audio control is done through the iDrive but common requests can be handled by steering wheel buttons as well. On cars with iDrive there is an 80GB hard-drive that has 15GB allotted to music storage, and it will contain CD contents for you.
The Z4 gets the next generation of iDrive (with navigation) and it is improved as much as anything on the car. Buttons have been added to the controller to speed access and operation is much more intuitive while maintaining the myriad functions. It might not be the best such system in modern automobiles but it should put an end to the criticism of earlier iDrive versions. Our only complaint is that the controller is located between the shift lever and the armrest and on gear changes we frequently bumped the controller, often executing a command or changing the radio station in the process. Automatics with paddle shifters won't have this problem, or manual-transmission non-navigation cars.
The parking brake is electrically operated by a switch behind the shifter, and it does get hot in sunshine, even underway. Concerns about starting on a hill without a lever to work are addressed by the start-off assistant that keeps the brakes applied momentarily while you engage the clutch and throttle. Switching for the suspension and transmission, where applicable, is to the left of the shifter so your hands never have to travel far.
On the 35i the optional dual-clutch transmission has a shift lever shared by some other new BMW products that's a bit unconventional and looks like a cross between a video-game controller and a beer tap. Neutral is the default position and park a pushbutton; push the lever forward to go backward and vice-versa, and, in manual mode, it shifts like a racecar with downshifts forward and upshifts back, allowing g-forces to assist the driver with shifting.
The top opens and closes in 20 seconds without any fear it will bump you on the head and once up felt just like a coupe in terms of noise; the headliner is off-white to enhance spaciousness. Raising all four windows (use the master switch on the driver's door) allows conversation at 75 mph with the top down, and most window-down wind noise comes from the area around the seatbelts. There is no wind-blocker panel for between the headrests, as specified in early option sheets, though we have seen photos and it may become available through your dealer.
Cargo room is about average for the class, but better with the top up (10.9 cubic feet). On cars with Comfort Access you can, through the key fob, lift the stowed roof out of the way for easier loading and unloading.
The interior of the sDrive35is includes a thick-rimmed M leather steering wheel with gearshift paddles, an M driver's footrest, and sport seats. Gray-faced instrument dials have an sDrive35is designation. Additional interior features include the Anthracite BMW roof lining, M door sill strips, floor mats with colored piping and the sDrive35is designation, and M trim in Aluminum Carbon.
BMW labels this Z4 an expression of joy. We usually just smile, and the Z4 may well bring a smile to your face, so we'll go along for now. While the retractable top and added features have nudged it a bit closer to grand touring car than sports car it is still clearly aimed at those who enjoy driving.
Both inline sixes are smooth as an America's Cup boat hull right to redline, deliver a sonorous note, are 3.0 liters in capacity and there ends most similarity. The 30i engine is a very light, modern, rev-happy unit that brings 255 horsepower at 6600 rpm and 220 pound-feet of torque at 2600 rpm; it has more than enough power for any road and delivers it in linear fashion, its output rising commensurate with revs. This package is EPA-rated at 18/28 mpg with both the manual and the automatics, numbers we easily met or exceeded.
Although also displacing 3.0 liters, the 35i's is a different engine altogether. It uses two very small turbochargers to boost maximum horsepower to 300 at just 5800 rpm and more noticeably, increase torque by 80 pound-feet to 300 from just 1400 rpm through 5000. The extra muscle gets the 210-pound-heavier 35i to 60 mph a half-second quicker than the 30i and delivers plenty of power for street and track alike. It will wind to 7000 rpm but there's really no point with that abundance of torque, and while it's a superb engine it doesn't offer the emotional happiness the 30i does.
EPA numbers are 18/25 mpg with the manual transmission and 17/24 mpg with the dual-clutch seven-speed. With decent aerodynamic drag numbers, a relatively small frontal area, and an efficient driveline we managed almost 24 mpg in a manual-transmission model over some amusing roads and 38 mpg/72 mph on an 80-mile leg from 4,000 feet elevation down to 700.
The six-speed manuals, both of them, offer soft, progressive clutch take-up for smooth starts whether crawling in traffic or weekend autocrossing. Shift action is light, short and semi-notchy, rather like there's a rubber-edged metal gate hiding under the shift boot. Shifts are quick, clean, and error-free.
The 30i automatic is a conventional six-speed unit and goes about its business exactly as intended; it's not as quick as the manual but costs only in purchase price and not fuel economy.
However, the stronger engine in the 35i gets an optional seven-speed dual-clutch automatic from the M3. Don't let the name confuse you: It does have clutches but they are all controlled by the car, the only coordination required is engaging D and pressing the gas. Around town you will feel like it has a momentary delay between when you press the accelerator from a stop and when the car starts moving; the actions behind this are also why it doesn't creep in gear as much as a conventional automatic.
Pushbutton mode changes allow you to ratchet up the speed and intensity with which it shifts to the point where it is faster than the manual and makes a milliseconds-long burp from the exhaust pipes as it rips through the gears. It's also smart, doing things like dropping gears automatically (rev-matching the downshifts) if you hit the brakes hard to go into a corner, but it will shy away from gear changes mid-corner so it doesn't upset the balance of the car. There is also a launch control mode for ultimate acceleration but read the owner's manual cautions on this before you take the steps and disappear in a wisp of tire haze.
Since it has more power and weight, the 35i gets substantially larger brakes. Brake performance and feel is good across the range, and we had no brake issues at all charging downhill in 100-degree weather in a 30i; those who consider themselves racers may opt for the 35i's bigger parts. The 35i also has wider rear wheels and tires to cope with the added weight and power.
A 35i with Sport Package, dual-clutch gearbox and 19-inch wheels arguably makes the better track car in terms of outright performance, but we found the 30i with Sport Package the sweeter ride on a winding road where the lighter weight is felt, reactions and response seem more linear, and the whole effect is more pure sports car than race car.
Expect the sDrive35is, with its 335 horsepower and 332 pound-feet of torque, and the overboost function that provides temporary doses of 369 pound-feet, to be even more exhilarating when you step into the throttle. This promises to be a very quick roadster, indeed, and will deliver performance levels exceeded by only the most powerful, and expensive, supercars. For those who want the ultimate Z4, the sDrive35is will surely fill the bill.
Even on the standard run-flat tires (no spare) and optional Sport Package the Z4 rides commendably well. Part of this is good suspension tuning, part from the rigid structure it's mounted to, and part from the adaptive damping included in the Sport Package that allows for Normal, Sport, and Sport-plus settings.
Steering is electromechanical but you'd never tell by how well it communicates what the front tires are doing. Unlike many sports cars, in which it seems that heavy steering was a design requirement, the Z4 is light around town, weights up nicely with cornering force and reminds us somewhat of the Honda S2000. It can't really match the surgical detail of the Porsche Boxster, but nothing at this price, short of a Lotus, does.
With a low center of gravity and near-perfect weight distribution with occupants, the Z4's handling is exemplary. You'd need something considerably lighter, more stiffly sprung, and equipped with fatter or stickier tires to make notably faster progress. Like the Mazda RX-8 (a light two-door, four-seat, front-engine, rear-drive coupe), the Z4 is not only nicely balanced and goes where you point it, it does so with little drama and it's relatively easy to find where its limits are.
Putting the top down doesn't change the behavior at all because it's the lightest such assembly in the industry (aluminum panels), changes front/rear balance by only 0.3 percent, and puts the weight of the top closer to the ground. You could argue lowering the top costs some rigidity as the triangulation between windshield, floor, and trunk is gone, but there is no cowl shake and only the inside mirror vibrated a bit on poor road surfaces so characteristics don't change.
The one thing you do have to get used to, depending on whether you're looking at the road or the hood, is what your brain might interpret as a momentary delay between when you turn the wheel and when the car rotates and changes direction. Since you sit so far from the front axle and very near the rear axle, steering input tends to send the hood off to one side before you feel the rear tires join the party. It's a sensation the more driver-forward Boxster and TT don't offer, and it's much more muted in the softer SLK.
Among the competitors, the SLK also offers a folding hardtop, while the Audi TT and Porsche Boxster use folding cloth tops; they're perhaps not as quiet and sealed as a hardtop, and not as easy to see out of, but trunk space doesn't suffer as much when motoring top-down. The TTS has the foul-weather bonus of all-wheel drive and a nicely finished cabin, but not the same balance and precision finesse as the Z4. The Mercedes offers many similar amenities but is less a driver's car and more a small version of the SL luxury convertible. The Porsche Boxster has an even better driving precision and the power of the 35i with the driver's engagement of the 30i, but its tariff can rise even faster than that of the Z4.
The BMW Z4 picks up right where the last generation left off, or as a more intimate, involving 6 Series cabrio. That it is a bit bigger and more luxurious doesn't indicate any loss of soul or enjoyment, and the folding hardtop offers the best of coupe and roadster forms with few of the drawbacks of either. We think it's the best sports car in this class, excepting, perhaps, the Porsche Boxster.
G.R. Whale filed this NewCarTestDrive report from Los Angeles.