Mercedes AMG-GT reviewed

  • Autocar India
  • Updated: Dec 08, 2014 12:30 IST

It may not have the iconic gullwing doors or the raw power of its predecessor, but the AMG GT feels more refined and better engineered than the SLS.

What is it?

The all-new Mercedes-AMG GT is the second production model to be conceived, engineered and developed at Mercedes-Benz’s performance car division at Affalterbach on the outskirts of Stuttgart in Germany. The indirect successor to the mighty SLS comes in two distinct guises: the standard GT has been launched internationally and the more powerful GT S driven in this review[N1] . It is expected to come to India at the end of 2015. As well as promising sharpened performance properties, the GT also aims to provide added levels of practicality over the significantly more expensive SLS, with which it shares various elements of its floorpan and driveline. Gone are the heavy gullwing doors and the traditional coupé layout, though. They are replaced by frameless front-hinged openings and a fastback body design with a large tailgate that opens up to reveal a 350-litre boot.

What remains of the first bespoke production model from Mercedes-AMG are the exaggerated proportions and vaguely retro aesthetic appeal, albeit in a more compact package. At 4546mm in length, 1939mm in width and 1289mm in height, the GT is 92mm shorter, the same width and some 27mm taller than the SLS, with which it shares key elements of its aluminium body structure. It also rides on a platform with a 50mm shorter wheelbase, at 2630mm, as well as tracks that are reduced by 2mm at the front at 1682mm and by 1mm at the rear at 1652mm. Eschewing the naturally aspirated 6.2-litre V8 multi-point injected petrol engine of the SLS, the GT is the first Merc-AMG model to adopt an advanced new twin-turbocharged 4.0-litre V8 direct injection petrol powerplant mounted well back in the engine bay for optimal weight distribution and low polar inertia – both crucial to top-notch handling properties. Loosely related to the 2.0-litre in-line four-cylinder direct injection petrol engine used in the more powerful version of the CLA and GLA. The 90-degree unit features turbochargers mounted inside the cylinder banks – a layout the performance wing claims boosts thermal efficiency, provides optimal throttle response and reduces emissions whilst providing for compact packaging.

Further highlights of the new engine, which was developed in-house and goes under the internal codename M178, include dry sump lubrication to better withstand cornering forces, and an exhaust system with fully variable exhaust flaps that allows the driver to vary the intensity of the engine's sound via a button on the centre console. The results look compelling on paper. The new V8 provides the standard GT with 456bhp at 6000rpm and 61.10kgm of torque between 1600rpm and 5000rpm. With added turbocharger boost pressure, output rises to 503bhp at 6250rpm and 66.22kgm from 1750-4750rpm in the GT S. By comparison, the standard SLS offered up 563bhp at 6800rpm and 66.22kgm of torque at 4700rpm. The car the GT S is really aiming at in pure performance terms, though, is the Porsche 911 Turbo. In its latest incarnation, the Porsche's twin-turbocharged 3.8-litre horizontally-opposed six-cylinder engine serves up 513bhp at 6000rpm and 67.33kgm at 1950rpm.

Channeling the heady reserves to the rear wheels is a revised version of the dual-clutch gearbox originally engineered by German specialist Getrag for the SLS. Mounted at the rear in a classic transaxle layout, the compact unit helps to provide the new model with a claimed 47 percent front and 53 percent rear weight distribution. The seven-speed transaxle gearbox has been heavily upgraded with a new electronic package that sees it offer up to five different operational modes: Controlled Efficiency, Sport, Sport Plus, Individual and, on the GT S only, Race. Further functions include automatic stop/start, brake energy recuperation and a coasting function that idles the engine on a trailing throttle in Controlled Efficiency mode.

Both GT models receive a standard locking differential, but whereas the standard GT gets a traditional mechanical unit, the GT S is fitted with an electronic function that is claimed to provide greater levels of traction by constantly varying the locking effect in acceleration and overrun. The GT is based around a magnesium and aluminium body structure produced by German construction specialist Thyssen Krupp – the same company that turns out body structure components for McLaren and Lamborghini. In standard GT guise, the new performance flagship tips the scales at 1540kg, while the GT S comes in at 1570kg.

What is it like?

The draw of the new model begins the moment you reach for the door handle, step over its broad sill and slide into the fabulous two-seat cabin. There is an appealing individualism and contemporary look to the design of the interior, which is terrifically well organised and imparts a feeling of real quality. You sit very low on seats with loads of lateral support and generous electronic adjustment. The heavily structured dashboard features an 8.4-inch monitor and no less than six round ventilation units, while the beautiful multi-function flat-bottomed leather steering wheel adjusts for both rake and reach and is ideally placed in a near-vertical position.

A pair of dials and a colour display reside in a heavily hooded binnacle ahead of the driver. All of the major controls are grouped in a panel atop the high-mounted centre tunnel between the driver and passenger. Much of the switchgear is unique to the GT; the main buttons and dials are superbly crafted and nicely weighted in their operation. Other less impressive switches are housed out of view within the roof liner. They may share a common silhouette, various structural elements and driveline components, but on the road, the differences between the SLS and the new GT S are immediately apparent.

From the very first mile, the new car feels a more rounded car than its predecessor, offering sharper step off qualities, terrific low-end tractability and superior gear shift quality along with added accuracy to the steering, and excellent low-speed manoeuvrability. All of this makes it a more gratifying car in everyday urban driving conditions. However, the ride, even in the softest of settings, is on the firm side. Up the pace on the motorway and you discover the core strength of the GT S: the sheer urge delivered by its engine.

Despite giving away 2226cc in swept volume to the naturally aspirated unit it replaces, the new twin-turbocharged engine is quite fantastic, with a wonderfully linear nature and no discernible lag. It's terrifically smooth and flexible across the entire rev range, and comes with a willingness to pull hard all the way to the 7000rpm redline, as well as a tremendous NASCAR-like soundtrack when you’ve got it operating in anything but Controlled Efficiency mode, in which the exhaust flap is closed off to muffle its aural traits. This inherent potency of the engine is backed up by much improved qualities from the reworked double clutch transaxle gearbox. It now shifts with added determination, especially in Sport Plus and Race modes, where ratios are engaged with great purpose.

According to the new car's performance figures, the GT S can crack 100kph in just 3.8sec – or 0.1sec faster than the original SLS. Aided by an active rear spoiler that deploys from the rear of the tailgate at 70kph to enhance longitudinal stability, it is also claimed to reach an electronically limited top speed of 310kph.

In a development first brought to the earlier SLS AMG Black Series, the GT S employs a damper between the engine block and floorpan. It is also the first Merc-AMG model to use active hydraulic engine mounts that continuously vary their firmness depending on the revs and yaw properties. Together, they are claimed to dramatically reduce the movement of the engine under load for added handling precision. Underpinning the new car is a bespoke aluminium suspension that employs traditional double wishbones up front and a complex double wishbone arrangement at the rear – in which the lower wishbones are connected directly to the wheel carrier for added wheel control and adjustment precision. Added to this are sturdy anti-roll bars and a set of standard 19-inch wheels shod with 255/35 front and 295/35 profile tyres. Allied to well-judged electro-mechanical steering, the assistance of which alters with speed, the new suspension endows the GT S with satisfyingly sharp responses and outstanding body control.

This, together with greater levels of compliance, offer a more refined feel and generally more determined nature than the SLS in just about every driving situation. There is terrific fluidity and pleasant directness to the handling, making the new car reassuring all the way up to and, when your mood permits, beyond its high limits of adhesion. The inherent accuracy and feel of the steering makes the GT S easy to place in corners.

The underpinnings also telegraph its actions with fabulous clarity, allowing you to push hard up to the apex and then get on the power earlier than you would have with the SLS. The sheer traction generated out of corners is exceptional and a clear nod to the deftness of the chassis tuning and expert calibration of the electronic stability control, which only ever springs into action when it is really required.

Provoke the GT S into a drift by turning off the electronic safety net, and it’s wonderfully progressive and fabulously engaging. The most impressive aspect, though, is the overall cohesion evident throughout the new car. The SLS was already a terrifically well balanced car with sufficient performance to unlock its potential. The GT S ups the ante by several steps. Subjectively, it feels quicker point-to-point yet more civilised over any road, its dynamic properties are sharper while the ride is more refined, and it is also better to listen to at full chat in Sport Plus or Race modes but less intrusive ambling along on part throttle loads in Controlled Efficiency mode. Coupled with the compelling ride quality, it all makes for a formidable grand tourer.

Hauling the GT S down the road proves no great drama, at least not with the optional carbon-ceramic discs fitted to our test car. An impressive 402mm in diameter at the front and 360mm at the rear, they initially lack for bite when driven away cold. But once you’ve worked some heat into them, they provide truly impressive retardation with nary a hint of fade, even after a decent stint on the track.

Should I buy one?

No doubt about it: its a sharper yet more refined prospect than the old SLS. It is a more rewarding car all round, whatever the driving conditions. Be it urban running, motorway cruising, back road running or race track work, it always feels able to operate beyond the already lofty levels of its predecessor. And at a much lower price, too. The only fly in the ointment on Indian roads could be its stiff ride. However, it’s not as stiff as the SLS was.

However, the new model (in GT S form especially) is up against some stiff supercar competition. It’s priced to rival the sublime Porsche 911 Turbo, and it’ll also likely feel the heat from the upcoming second-generation Audi R8, which is due to arrive after the GT S hits Indian showrooms.

What distinguishes the new flagship is the brilliant blend of performance and practicality. It’s a user-friendly sports car that would feel equally happy having a blast on the Buddh circuit or rumbling down Rajpath.

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