- Refined and free-revving six-cylinder engines
- Short-throw manual transmission has precise action
- Impressive dynamics
- Steering is direct…
- … but becomes light at higher speeds and lacks feel on-centre
- Firm ride
- On uneven surfaces, front wheels follow undulations (‘tram lining’)
- Lacks agility and poise of Porsche 987 Boxster
Review: BMW E85.I Z4 Roadster (2003-06)
Overview
Released in July 2003, the BMW E85 Mk.I (E85.I) Z4 Roadster was a two-seat convertible with a soft-top roof. Manufactured in South Carolina, USA, the rear-wheel drive Z4 Roadster was available with BMW’s 2.5-litre M54 B25 and 3.0-litre M54 B30 inline six cylinder petrol engines, for the 2.5i and 3.0i variants respectively. These engines featured double overhead camshafts, four valves per cylinder, variable valve timing for intake and exhaust valves and electronic throttle control.
Compared to its E36/7 Z3 Roadster predecessor, the E85 Z4 Roadster was 66 mm longer (at 4091 mm), 89 mm wider (1781 mm), 11 mm taller (1299 mm) and had a 49 mm longer wheelbase (2495 mm). Furthermore, the Z4 Roadster had MacPherson strut front suspension and multi-link rear suspension.
| Variant | Engine | Trans. | Peak power | Peak torque |
|---|---|---|---|---|
| 2.5i | 2.5-litre petrol I6 (M54 B25) | 5sp man., 5sp auto |
141 kW at 6000 rpm | 245 Nm at 3500 rpm |
| 3.0i | 3.0-litre petrol I6 (M54 B30) | 6sp man., 5sp auto |
170 kW at 5900 rpm | 300 Nm at 3500 rpm |
Safety equipment
Standard safety equipment included dual front airbags, front side (thorax) airbags, ABS, electronic stability control, cornering brake control, traction control, twin fixed rollover hoops and front seatbelts with pretensioners and load limiters.
Euro NCAP crash testing
In Euro NCAP crash testing , the 2.5i variant received a five star adult occupant protection rating with a score of 31.35 out of 37. In the offset crash test, protection from serious leg injury was marginal for the driver, though head and chest protection were good. In the side impact test, there was a slight risk of serious chest injury for the driver.
Features
Standard features for the 2.5i included 16-inch alloy wheels with runflat tyres, an eight speaker stereo with CD player, climate control air conditioning, leather seats, power adjustable and heated seats with driver’s seat memory settings, cruise control, front fog lamps, automatic headlights, rain-sensing wipers, a leather-wrapped steering wheel, remote central locking, power windows and mirrors, a tilt and reach adjustable steering wheel, heated rear window, trip computer and an immobiliser. Furthermore, the Z4 Roadster’s power operated roof could be lowered in approximately ten seconds.
The 3.0i was further equipped with 17-inch alloy wheels and an upgraded braking package, a ten speaker HiFi stereo with a six-disc CD player and interior lighting package.
Review: BMW E85.II Z4 Roadster (2006-09)
Overview
Released in April 2006, the E85 Mk.II Z4 Roadster introduced new engines, transmissions, safety equipment and features. Visually, the E85.II Z4 Roadster could be identified by its new bumpers with rectangular fog lights for the 2.5si and 3.0si, wider front air dam with more pronounced edges, reshaped grille, modified tail-lights and new interior trims.
The 2.5i and 3.0i variants were replaced by the 2.5si and 3.0si which were powered by BMW’s N52 B25 and N52 B30 engines, respectively. Compared to their M54 predecessors, the N52 engines introduced variable valve (BMW’s valvetronic) and had crankcase made entirely of magnesium and aluminium. A high-performance M variant – powered by BMW’s S54 B32 engine – was also introduced. Other changes included the introduction of a six-speed ‘Steptronic’ automatic transmission (with steering wheel gearshift paddles) and ‘Dynamic Drive Control’ with selectable modes.
| Variant | Engine | Trans. | Peak power | Peak torque |
|---|---|---|---|---|
| 2.5si | 2.5-litre petrol I6 (N52 B25) | 6sp man., 6sp auto |
160 kW at 6500 rpm | 250 Nm at 2750-4250 rpm |
| 3.0si | 3.0-litre petrol I6 (N52 B30) | 6sp man., 6sp auto |
195 kW at 6600 rpm | 315 Nm at 2750 rpm |
| M | 3.2-litre petrol I6 (S54 B32) | 6sp man. | 252 kW at 7900 rpm | 365 Nm at 4900 rpm |
Safety equipment
Compared to its E85.I predecessor, standard safety equipment for the E85.II Z4 Roadster was extended to include brake assist and electronic brake force distribution. The stability control system was also upgraded to include brake standby, brake drying and brake fade compensation functions.
Features
Compared to its 2.5i predecessor, standard features for the 2.5si included 17-inch alloy wheels, Bluetooth connectivity, rear fog lamps, an electrochromatic rear view mirror and tyre pressure monitoring. Compared to the 3.0i, the 3.0is added 18-inch alloy wheels and heated mirrors.
Z4 M Roadster
The Z4 M Roadster was distinguished by its 18-inch double-spoke light alloy wheels, lowered and firmer ‘M Sport’ suspension, conventional tyres (i.e. not run-flat), upgraded braking package, electronic differential lock and hydraulic steering system. Visually, the M Roadster could be identified by its more aggressive front air dam with three air intakes and rear diffuser.
Furthermore, the M Roadster featured a ‘BMW Professional’ HiFi system, Nappa leather ‘M Sport’ seats, satellite navigation with colour display, bi-xenon headlights with washers, voice recognition, rear parking sensors, an ‘M’ leather-wrapped steering wheel and gearshift knob, TV tuner and tyre pressure monitoring.
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