A new SL is a rare event on the Mercedes-Benz launch calendar: the R230 model revealed in Hamburg on July 31st is only the fifth generation of the company's flagship sports car family since 1954, writes Angus MacKenzie.

Mercedes-Benz passenger car chief Jurgen Hubbert spoke at length of the passion and emotion surrounding the SL name, and drove one of the legendary 1950s 300SL 'Gullwing' coupes onto the stage during the glitzy launch presentation to emphasise the point. But first impressions of the R230 are of a car that is coolly predictable and ruthlessly competent. In other words, it's a typical flagship Mercedes.

Assembled at Mercedes-Benz's Bremen plant, which has been given a 200 million euro ($US177 million) upgrade to handle the new car, the R230 is built on an all-new platform. Compared with the outgoing R129 model, which entered production at Bremen in 1989, it is 36mm longer and 6mm wider overall. The wheelbase has grown by 45mm to 2650mm, subtly altering the proportions, and allowing for a 50mm increase in seat travel.

The new R230 - another coolly predictable and ruthlessly competent flagship Mercedes
The new body-in-white is 20% stiffer and boasts better crash performance thanks in part to a 73% increase in the use of high strength steel. But extensive use of lightweight materials - aluminium for the bonnet, front wings, doors and boot lid; magnesium for the door inners; thermoplastic for the entire fuel tank well - have kept weight to 405kg, identical to the R129.

In design terms, the new SL brings together what are now familiar Mercedes-Benz design cues - blended quad headlights and strikingly sculpted surfaces - in a tautly constructed package. The side and cowl vents, with their faux guard bars, pay obvious homage to the 300SL, although Mercedes-Benz head of design Peter Pfieffer insists it is still a forward-looking design. He does admit, however, that with an average age of 48, and a 75% loyalty rate, the company doesn't want to alienate existing SL buyers.

The car was designed under the direction of 36 year old British designer Stephen Mattin, who used the packaging of the all-metal folding roof as his starting point. The roof is similar in concept to that which debuted on the smaller SLK. But articulation is different - the backlight rotates in the opposite direction to that of the SLK, so it fits more snugly against the roof centre - increases available luggage space. The roof takes just 16 seconds to complete a cycle, two-thirds the time of the SLK version, and can be actuated remotely using the electronic 'key'.

The interior is dominated by the heavily cowled instrument cluster and substantial centre console
Despite its longer wheelbase, the R230 is strictly a two seater. The interior features elegantly curved forms and is dominated by the heavily cowled instrument cluster and substantial centre console. The instrument faces feature retro-style graphics, and a brushed aluminium finish is used to highlight switches and latches. The seats, with their integrated seat belts, are related to those used in the CL.

Buyers can choose from two types of leather and five colour schemes, with the choice of chestnut, burr walnut, black ash or aluminium trim available on the centre console. An optional bag can be strapped to the rear firewall behind the passengers to increase luggage capacity. However, the quality ambience of the interior is let down a little by the plasticky appearance of the minor switchgear and the wobbly feel of the cleverly integrated heat/air-con controls as they move on their armatures.

Under the skin, the new SL follows familiar Mercedes-Benz practice, albeit updated and uprated where necessary. The damper strut suspension arrangement of the previous model has been replaced by a four link layout, and the old recirculating ball steering system was pensioned off in favour or rack and pinion. At the rear is Mercedes-Benz's formidable multi-link suspension, but for the first time it's fashioned entirely from aluminium, reducing the weight of the assembly by about one-third. Standard wheels are 17 inch diameter, with 255/45 tyres. Larger 18 inch wheels with 285/35 tyres for the rear, are available as an option.

Just one engine, the 5.0 litre V8 shared with the CL, S-class and previous SL, will be available at launch. With 306 bhp at 5600rpm and 460Nm at 2700 rpm it will propel the new SL500 to 62mph in 6.3 seconds, according to DaimlerChrysler figures, two tenths of a second quicker than in its predecessor. Claimed NEDC combined fuel consumption is unchanged, however, at 12.7 litres/100km.

The SL55 AMG version, powered by a 430bhp, 5.5 litre supercharged V8,
will be revealed at the Frankfurt
motor show
A more potent SL55 AMG version, which is expected to be powered by a 430bhp, 5.5 litre supercharged V8, will be revealed at the Frankfurt motor show next month and the range will eventually be broadened with the addition of an entry level SL320 model, powered by the 3.2 litre V6, and a top of the range SL600, powered by the 6.0 litre V12 used in the CL and S-class. Prices in Germany are expected to start at just under 75,000 euros ($US66,000) for the SL320, rising to just over 94,000 euros for the SL500 and stretching to more than 124,000 and 127,000 euros respectively for the SL55 and SL600.

As expected in a flagship Mercedes, the new SL bristles with high technology. Active Body Control, which debuted on the CL, is standard, along with two stage airbags and automatic headlights. Options include the Distronic active cruise control system, a tyre pressure monitoring system, and the card-activated keyless entry and start system.

The SL's headline technology, however, is the world's first production brake-by-wire system, called Sensotronic Brake Control (SBC). The system is controlled by a central processor that analyses data from sensors monitoring the brake pedal, and the anti-lock braking and stability control systems. The SBC computer regulates the pressure in a high-pressure brake fluid reservoir, and the braking force required for each individual wheel via four wheel pressure modulators.

The SL's headline technology is the world's first production brake-by-wire system, called Sensotronic Brake Control (SBC)

DaimlerChrysler claims the system allows faster, more secure braking in all conditions. In an emergency, the SBC system will recognise the fact the driver has lifted his foot rapidly from the accelerator and will automatically move the brake pads onto the discs, ready for application, reducing the distance needed for an emergency stop from 120km/h by 3%. The system not only works in tandem with the ESP stability control system, but also automatically adjusts the brake force pressure on each wheel during cornering. In wet weather, the system will automatically pulse the pads against the discs at regular intervals to remove any film of water.

The previous two SL models stayed in production for 18 and 12 years each, reaching a total of 237,000 and 204,000 units respectively. Significantly, this new SL is destined for a much shorter model cycle - it will be replaced in 2009. Jurgen Hubbert admits the company is banking on higher annual sales and lower production costs for the car to make a positive contribution to the bottom line.

"We have learned that with the competition we have these days there is no chance of 18 year or 12 year model cycles anymore," Hubbert says, "so we have to find solutions to make such a project feasible under different conditions." Hubbert won't say how much cheaper the R230 is to build than its predecessor, but will admit to a percentage improvement that's in "double figures".

Company sources admit total planned production is about 175,000 units, which represents a 28% uplift in the annual sales rate over the outgoing model. That's a tall order, especially as the high end roadster and coupe sector of the market is expected to remain more or less static. That means DaimlerChrysler is looking at substantial conquest sales - at least 30% - to meet its target.

To view related research reports, please follow the links below:-

DaimlerChrysler Strategic Review (download)

The world's car manufacturers: A financial and operating review