Monday, November 11, 2013

Mercedes SLS AMG replacement to rival Porsche 911 Turbo


SLS AMG due for retirement next year, new £100,000 Mercedes SLS replacement due to go on sale in 2015

The latest spy shots show that Mercedes-Benz’s AMG performance car division is putting the finishing touches to its new 493bhp twin-turbocharged 4.0-litre V8 flagship sports car, which will replace the Mercedes SLS, nine months before it is scheduled to be revealed at next year’s German grand prix.

Developed under the codename C190, the new two-seater has been conceived to replace the four-year-old SLS at the head of the German manufacturer’s line-up when that car is retired in July next year.



The new model aims to challenge the heady performance, lofty dynamics and everyday driving appeal of the latest Porsche 911 Turbo at a price, insiders suggest, that will be close to £100,000 when UK sales begin in early 2015.

Originally tipped to receive the SLC name first used by the SL coupé in 1971, the new front-engined sports car is now expected to be called GT, according to highly placed sources at Mercedes-Benz. The sources confirm the new car will be assembled on the same production line used for the soon-to-be-discontinued SLS at AMG’s headquarters in Affalterbach, Germany.

The basis for the Mercedes-Benz GT AMG is a predominantly aluminium spaceframe chassis, elements of which are shared with that employed by the SLS. It is allied to suspension consisting of double wishbones up front and multi-links at the rear, featuring variable damping along with a raft of electronic driver aids. The body uses a combination of aluminium and composite panels.

The GT follows the SLS’s lead in boasting a distinctive cab-back profile with a long probing bonnet and short rear deck, proportions dictated by the original SL. But in a bid to improve usability and appeal to a broader group of prospective customers, the new Mercedes-Benz adopts conventional front-hinged doors in place of the SLS’s gullwings.

Another key change in design is the adoption of a liftback-style rear hatch, enabling easier access to the luggage compartment than a conventional boot. As with the SLS, an electronically controlled spoiler deploys from the rear of the boot lid to provide added downforce at speeds above 75mph.

Preliminary figures put length at 4500mm, which suggest that the new GT will be 140mm shorter than the SLS. Width and height are close to those of the SLS at 1939mm and 1287mm respectively. It rolls on standard-issue 19-inch wheels shod with 265/35 front and 295/30 rear tyres

The GT eschews both the naturally aspirated 6.2-litre V8 engine found in the SLS and twin-turbocharged 5.5-litre V8 mill that powers other AMG models to become the first Mercedes-Benz to host a new twin-turbocharged 4.0-litre modular V8.

The new engine, also set to appear in a successor to the C63 AMG, shares its architecture with the turbocharged 2.0-litre in-line four-cylinder engine used in the recently introduced A45 and CLA45. Endowed with a 90deg cylinder bank angle, the V8 is mounted low and 
well back in the engine bay, almost entirely behind the front axle line for the best possible weight distribution.

Official output figures are yet to be disclosed, but AMG insiders have indicated that the new engine has been tuned to deliver somewhere in the region of 493bhp, yielding a specific output of 123bhp per litre. This pitches the GT’s output into the same territory as the Porsche 911 Turbo, which generates 514bhp.

Despite giving away over two litres in engine capacity to the SLS, the application of forced induction sees the GT’s torque reserves swell to a similar level at 480lb ft. But while peak torque for the SLS arrives at a relatively high 4750rpm, the GT will deliver maximum twist below the 2000rpm mark.

These heady reserves are channeled via a lightweight carbonfibre propeller shaft to a seven-speed dual-clutch automatic gearbox mounted within the rear axle assembly, a layout that helps to provide the GT with a 48 per cent front, 52 per cent rear weight distribution. A mechanical locking differential is then used to apportion drive between the rear wheels.

The gearbox is described as being a development of the Getrag-produced unit used in the SLS. It has been upgraded to include an automatic stop-start function for added fuel savings in city driving. Brake energy recuperation is used to boost driveline efficiency, while new software mapping is claimed to improve the quality of gear changes.

With a predominantly aluminium structure and other lightweight construction measures helping to suppress kerb weight to around 1550kg (which is 145kg less than the SLS) the GT is claimed to yield a power-to-weight ratio of close to 320bhp per tonne.

Straight-line performance is yet to be officially certified, but Mercedes-Benz sources hint at a 0-62mph time of “well under 4.0sec” and a top speed “above 190mph”. At the same time, they claim the new two-seater will return combined-cycle fuel consumption of “close to 30mpg”.

Mercedes-Benz’s AMG division has left no stone unturned in its bid to provide the C190 with class-leading dynamics. The chassis, while sharing components with the SLS, boasts unique geometry. The new Mercedes-Benz 
sports car also adopts an electro-mechanical steering system that’s sourced from the new C-class and replaces the hydraulic set-up used by 
its predecessor.

In a move that has infuriated rival Porsche, AMG has secured the services of Markus Hofbauer, the man credited with much of the chassis development carried out on the latest 911. He has been charged with the task of fine-tuning the handling of the GT, which is already said to lap the Nürburgring circuit faster than the standard SLS.

source: autocar