The BMW Z4 is a two-seat roadster with a retractable hardtop. With the top up, the Z4 is like a coupe, offering the benefits of a hardtop: better security, superior chassis rigidity, less obstructed rearward visibility, better interior isolation and better protection from the weather. Drop the top, and it's a roadster.
For 2011, the BMW Z4 sDrive35is joins the lineup. The Z4 sDrive35is delivers even more performance than the already-quick Z4 sDrive35i. It comes with enhanced aerodynamic and handling features, unique wheels, distinctive exterior trim and details, and interior comfort and feature upgrades. It is as close as to a high-performance M model as BMW will offer because there no plans for a Z4 M (that we know of, that is).
A new M Sport package is available for the 2011 Z4 sDrive30i model. Otherwise, the Z4 lineup stays mostly pat, adding smartphone integration for 2011. The current BMW Z4, introduced for the 2009 model year, is the second generation of the Z4 name (first launched in 2003).
The Z4 offers the driving character you expect from BMW and it will be familiar to any fan of the brand. The performance and feel of balanced precision is there in every Z4. We like the base Z4 sDrive30i with its free-revving engine, equipped with the manual gearbox and no iDrive, no navigation system. We feel the highly optioned Z4s weigh more and tend to feel more like grand touring machines than sports cars. The high-performance sDrive35is with the dual-clutch gearbox gets close to 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.
Classic roadster proportions give the Z4 a long hood and short decklid, shoulders over the wheel arches and tapers in three axes. Creases begin 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 someone traced 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 its closed profile is similar to that of the Mercedes SLR. Gills behind the front wheels carry the substantial badges, and the side signal repeaters are located behind opaque panels in the gills; the BMW propeller logo is still here, but no longer serves to disguise the turn signal repeaters.
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 on rough roads, and some wheel styles will require more cleaning effort.
From dead-on at either end with the top down, the 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 and 35is have a single outlet on each side, a la Z8.
Exterior trim varies among the three models. The shape of the front of the car is the same for all models, illuminated with BMW's trademark corona daytime running lights (programmable). The sDrive30i 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, and the 35is has wider spacing of its grille vanes. While the Z4 is close to the ground, it is not prone to scraping at every speed bump or mild driveway entrance because the front overhang is shorter than that of many other sports cars. Short overhangs are better for handling.
The Z4 sDrive35is gets some other exterior changes. The M Sport package is standard, so it has a 10 mm lower ride height and different front and rear styling. The 35is modifies that styling with horizontal bars in the front outer air intakes and a body-color rear apron with a black lower diffuser. It also has oxide silver mirror caps, and a unique design for both the standard 18- and optional 19-inch wheels.
The Z4 is longer than the Audi TT and Mercedes-Benz SLK, and it's shorter than the Porsche Boxster, though the difference among them is only a few inches. In height and width, they are much closer, so exterior dimensions should not factor into purchase decisions.
The Z4 is built in Regensburg, Germany. In BMW fashion, many systems on the Z4 have been proven in other recent BMW models, including the higher-output engines, 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).
The sDrive35is has dark gray-faced gauges with lettering on the tachometer face identifying the model. The 35is also has a thick-rimmed M leather steering wheel with shifter paddles, driver's footrest (dead pedal), and sport seats. Additional interior features include the Anthracite BMW roof lining, M doorsill strips, floor mats with colored piping and model designation, and M trim in Aluminum Carbon.
The sDrive30i comes with leatherette upholstery (vinyl), but that is available only in black. Black may not be the best in sunny areas where you're likely to park the car with the top down. Order leather and the palette increases to five colors with only one of them dark. The leather was selected with a convertible in mind. You can also opt for the 35i or 35is models and choose from nine colors of leather; you can even extend the leather coverage for the ultimate in premium feel. The low-gloss brushed aluminum or ash wood trim (which we found 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. Unlike an SUV, where you sit upright, though, you sit much lower and with your legs stretched out in front of you in the Z4. 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 on which to rest or brace your left foot.
Cubby 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. Cars ordered without the navigation system get a cubby atop the dash (and that's how we would order ours). 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 into 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. The M Sport wheel is thicker, but it feels great in the driver's hands. Ahead of the wheel are a large speedometer and tachometer, 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 mostly unobstructed because the folding top design includes two small windows. Even the 8.8-inch stowable navigation display (1280x480p) is easy to read in direct sunlight, polarized sunglasses or not.
Climate control is manual in the 30i and automatic dual-zone in the others 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. Turn the control wheel from warm to cool and the response is immediate, as is the case 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 by depressing and holding.
Audio options include HD radio, satellite radio, a glovebox-mounted six-disc DVD changer, iPod and USB ports, and 14 speakers driven by an amplifier capable of delivering 650 watts. iDrive is standard in navigation-equipped cars, and it absorbs much of the audio control, but common requests can be handled by steering wheel buttons as well. Cars with iDrive have an 80GB hard-drive with 15GB allotted to music storage.
The Z4 was the first BMW with the newest generation of iDrive, and it is much improved. Buttons have been added around the controller to speed access, making operation much more intuitive while maintaining the myriad functions. 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. Cars without navigation or with the automatic or DCT transmissions and paddle shifters won't have this problem. While the iDrive system is improved, we are not fans.
On manual shift cars, 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. The buttons for the Driving Dynamics Control are located to the left of the shifter, so your hands never have to travel far. The parking brake is electrically operated by a switch behind the manual shifter, and it does get hot in sunshine, even when on the road.
Z4 sDrive35i and sDrive35is models with the DCT have 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 is a pushbutton; push the lever forward for Reverse and backward for Drive. In manual mode, it shifts like a racecar with downshifts forward and upshifts back, allowing g-forces to assist the driver with shifting. The same goes for the steering wheel buttons. While this setup would seem to make sense, we much prefer the steering wheel paddles in other BMWs. They are larger and the left paddle is for downshifts and the right for upshifts. easier to use.
The top opens and closes in 20 seconds without any fear it will bump you on the head. Once up, the Z4 feels just like a coupe in terms of noise abatement. 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 (8.0 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 BMW Z4 is clearly aimed at those who enjoy driving. The retractable hardtop and added features have nudged it a bit closer to grand touring car than sports car. The inline six-cylinder engines rev smoothly to redline.
The sDrive30i 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 automatic, numbers we easily met or exceeded when we drove one. This is a delightful engine, particularly with the manual.
The sDrive35i engine is a different animal altogether. It uses two very small turbochargers to boost maximum horsepower to 300 hp at just 5800 rpm. Even more noticeably, the turbos increase torque to 300 foot-pounds, on tap from just 1400 rpm through 5000. The extra muscle gets the sDrive35i (210 pounds heavier) to 60 mph a half-second quicker than the sDrive30i. That's 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 delightful rev-happy feel the sDrive30i does. EPA numbers for the sDrive35i are 18/25 mpg with the manual transmission and 17/24 mpg with the DCT. 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 at 72 mph on an 80-mile leg from 4,000 feet elevation down to 700.
The sDrive35is model has a more powerful version of the twin-turbo engine. Turbo boost increases from the sDrive35i's 8.7 psi to 11.6 psi in the sDrive35is, plus an overboost mode allows for 14.6 pounds of boost for up to seven seconds. Those changes increase horsepower to 335 and up torque to 332 pound-feet. The overboost feature adds another 37 pound-feet of torque for a total of 369. Aggressive exhaust tuning gives the sDrive35is a great burble. The extra boost cuts 0.3 off the 0-60 mph time, which is an impressive 4.7 seconds. It comes only with the DCT. Fuel economy is the same as in the sDrive35i at 17/24 mpg.
The 6-speed manual transmissions for the sDrive30i and sDrive35i 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 sDrive30i automatic is a conventional 6-speed unit and goes about its business exactly as intended; it's not quite as quick as the manual, but it's easy to operate and more practical for commuting in heavy traffic.
BMW's 7-speed DCT dual-clutch automated manual transmission comes standard in the sDrive35is and is optional for the sDrive35i. Also used in the M3, this transmission has clutches, but there is no clutch pedal. Put it in Drive and step on 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 DCT can shift faster than a manual transmission, emitting brief burps from the exhaust pipes as it rips through the gears. It's also smart, dropping gears automatically (rev-matching the downshifts) when you brake hard for a corner, but it will shy away from gear changes mid-corner so it doesn't upset the balance of the car. There is a launch control mode for ultimate acceleration, but make sure to read the owner's manual cautions before you take the steps and disappear in a wisp of tire haze.
Brake performance and feel is good across the range. We had no brake issues during a day at the track in the sDrive35is. Nor did we experience fade when charging downhill in 100-degree weather in an sDrive30i. Since they have more power and weight, the turbocharged sDrive35i and sDrive35is get substantially larger brakes, and that may be a deciding factor for drivers intending to take their Z4 to track events. These models also have wider rear wheels and tires to cope with the added weight and power.
Every Z4 is fun to drive, however. We found the sDrive30i with the Sport Package to be a sweet ride on a winding road where the lighter weight is felt. Compared to the sDrive35i, reactions and response seem more linear, and the whole effect is more pure sports car than racecar.
The sDrive35i, however, has considerably more power that keeps coming on strong. Speed merchants will prefer it.
For the ultimate performance, though, the sDrive35is is the clear choice. It delivers performance levels exceeded by only the most powerful, and expensive supercars. We had the opportunity to drive it on a racetrack and there it felt right at home, hunkering down through corners, accelerating willingly, braking with power, and staying flat and balanced. For those hoping for a Z4 M, this is as close as it gets.
We found the Z4 rides commendably well, even on the standard run-flat tires (no spare) and optional Sport Package. Credit the rigid structure, BMW's magical suspension tuning, and the technology involved in the standard Driving Dynamics Control. Driving Dynamics Control adjusts steering feel, throttle response, and the limits of the stability control system, and when paired with a sport package it adds electronic control of the shocks. It has Normal, Sport, and Sport-Plus settings. The Normal mode is the most relaxed, and it's the choice for the highway or around-town cruising. Sport and Sport-Plus sharpen the responses and firm up the ride. These modes are meant for more spirited driving. Choose the mode that fits your preferences, mood and situation.
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 steering is light around town, weights up nicely with cornering force and reminds us somewhat of the Honda S2000. The sDrive35is model is a bit quicker and sportier. Still, 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. 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 thanks to aluminum panels. It 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 little-to-no cowl shake. We found that the inside mirror and only the inside mirror vibrated a bit on poor road surfaces, a sign that body rigidity characteristics don't change much top up or top down.
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 inputs tend to send the hood off to one side before you feel the rear tires joining the party. It's a sensation the more driver-forward Audi TT doesn't exhibit, and it's much more muted in the softer Mercedes-Benz SLK. Nor does the mid-engine Porsche Boxster exhibit it.
Among the competitors, the SLK also offers a folding hardtop, while the TT and Boxster use folding cloth tops. Cloth tops are 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 Audi 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 Boxster has even better driving precision, with power comparable to the sDrive35i and the driver's engagement of the sDrive30i, but the Boxster tends to cost more.
The BMW Z4 reminds us of a more intimate and engaging version of the 6 Series cabrio. The folding hardtop offers the best of coupe and roadster forms with few of the drawbacks of either. The sDrive35is model carries a hefty premium, but it is the most powerful and the best performer. We recommend the base Z4 sDrive30i with its lively engine, especially with the manual gearbox; order ours without the distracting iDrive. We think the Z4 is the best sports car in this class, excepting the Porsche Boxster.
G.R. Whale contributed to this NewCarTestDrive.com report from Los Angeles, with Kirk Bell reporting from New Jersey.