The BMW Z4 Design Chassis

The BMW Z4 Design Chassis

The BMW Z4 is a model roadster of automaker BMW . This article looks at the 2009 version of the Z4, known internally as BMW E89 , replacing the BMW E85 . For the first time in its history, to compete with the competition Mercedes-Benz and its roadster SLK , the Z4 is equipped with a retractable hardtop. This new Z4 will also be split into two separate vehicles, coupe and roadster, but will only be available in a convertible version.

This second generation of BMW Z4 is first presented via the Internet in early 2009 , then physically during the 2009 edition of the Salon de Detroit . Now manufactured in the Regensburg factory in Germany, and no longer in South Carolina in the United States, the BMW Z4 is launched on May 9, 2009 at a base price of around € 35,900 .

Major disruption in the design office of the German brand BMW: the iconic American designer Christopher Edward Bangle , present for 17 years at the head of this office, leaves the mark and leaves its place to Adrian van Hooydonk 1 . The designer begins a real evolution of which the Z4 is the first to benefit.

Since 1934 , BMW has been offering its customers “elegant and powerful roadsters” , so that this new generation had to respect the established stylistic codes, namely a long bonnet, marked wheel arches, a short rear and a protective cover. inclined breeze . So it was the project of two women, Juliane Blasi for the exterior design and Nadia Amaout for the interior design, which prevailed 2 . Juliane Blasi is actually the winner of a competition to BMW between studios in Munich and California bringing together forty projects 3 .

The lines are less aggressive, more sober, in fact, the opposite of the previous generation 5 . The BMW Z4 is the only two – seater roadster to combine the classic proportions of the cabriolet with a low, reclining seat on the rear axle 6 , 7 . The sides, boosted by a pronounced line stretching from the grille to the rear wheel arches, say the sporty character ( ” athletic look ” ) of the Z4 6 , 8 . The famous BMW grille, forming two whiskers, is slanted overhanging, pronouncing more the features of the “nose squale” of the automobile 9. The shield is scratched with a blade, on either side of the air vent, while the trunk receives new original lamps 5 . According to the Automobile Monitor , the BMW Z4 now has “the slender elegance of a large coupé” 10 .

Inspired by the BMW Z8 , the interior benefits from an “irreproachable” finish 11 . Some may nevertheless be disappointed by the perceived quality due to perfectible adjustments 12 . The controls feature chrome while the dashboard is embellished with leather and precious wood. The seats are, as standard, completely covered with leather 9 . They are also treated to prevent the sun from heating the seats and burning the occupants 13 . For this, the SunReflective technology used by BMW consists of incorporating specific pigments into the leather that ensure the reflection ofinfrared rays of sunlight 14 .


The Z4 of the BMW advertising campaign ” An Expression of Joy ” , exhibited at the New York Motor Show .
The major novelty of the BMW Z4 is the abandonment of the retractable canvas in favor of a two-part aluminum hardtop , the electro-hydraulic opening takes place in 20 seconds. Manufactured by the equipment manufacturer Edscha, the operation can no longer be performed by traveling up to 30 km / h as on the previous version but only at stop 15 . The reasons for this change are diverse: Peripheral visibility – 14% increase on average 8 – and increased rear 3/4, improved acoustics , security against vandalism 16 , 3 .

Moreover on the Z4e89 23i and 30i the weight remains almost identical to the version E85 2.5si and 3.0si.

On the other hand, the Z4 35i / 35is weighs 1,590 kg empty , 120 kg more than the atmospheric engines.

Aluminum is also the double-hinged front axle of the rocket pivots, resulting in a 30% reduction in weight to an equivalent steel construction . The balance of the load on the axles is thus improved, “guaranteeing increased agility and precise road behavior” 17 . The front axle is a MacPherson axle while the rear uses a center bar. A dynamic control system – a system that modifies the progressivity of the accelerator, the response of the engine, the ESP and the law of the steering assistance – is proposed as standard in order to create a high-performance adaptive chassis. performance 18 .

The canvas hood of the BMW E85 is abandoned in favor of a retractable roof.
Taking advantage of an 11 cm long chassis , bringing its total length to 4.23 m instead of 4.09 m for its predecessor, the BMW Z4 announces a trunk volume rising, reaching 310 dm 3 with the roof. instead of 260 dm 3 for the BMW E85. Due to the German roof option, this volume decreases to 180 dm 3 in a convertible version 19 , 20. Black point on the board of the Z4, the total access to the trunk proves impossible when the roof is retracted, it is however possible to access it for small items stored at the edge; it will therefore, in most cases, load his luggage before decapoter and do the reverse manipulation to extract them