Mercedes-AMG GT S 2014 Review

Mercedes-AMG GT S

A model unique to Mercedes-AMG, the GT S is a pure two-seat sportscar that makes few if any compromises in terms of performance. Powered by a new twin-turbo V8, it’s supercar fast and racetrack ready, yet it spoils its occupants with a luxurious cabin, decent space, excellent levels of refinement and the sort of safety and amenity systems you’d expect from a top-line Mercedes. AMG insists it's not targeting 911, but we think it’s got very close to the bullseye.

Benz has gone from the name – replaced by AMG. And with the change comes serious intent. Intent to concentrate on performance, with an even more single-minded focus. Intent, whether spoken or otherwise, to take on the world’s favourite sportscar, Porsche’s 911.

That the new Mercedes-AMG GT S is fast is a given. That it has the ability to rival, let alone displace, what’s acknowledged as the world’s most accomplished mass-market sportscar takes a little more imagination.

We knew the AMG team was zeroing in on the target after just a few laps of Willow Springs circuit in the SLS Black. Although the hardware changes weren’t massive, the Black was a very different car from the cooking model SLS that went before it.

And in the GT S, AMG has taken another step along the performance road. It might not have the raw power or speed (or iconic gullwing doors) of its predecessor, but make no mistake this is already a wickedly capable and rapid sportscar that is (forebodingly for others) just at the very start of its development lifecycle.

The heart of the GT S is a new direct-injection 4.0-litre twin turbo petrol V8 that has familial links with the 265kW 2.0-litre turbo four that powers the A 45 AMG. The GT S is the first application for the new engine that is characterised by turbos located within the vee — a concept used by others including BMW but dubbed “Hot inside V” by the Affalterbach crew.

AMG claims this set-up benefits packaging but it also reduces the length of inlet tract and minimises turbocharger lag and hence helps deliver engine characteristics more akin to an atmo engine.

In its current top GT S spec, the engine pumps out 375kW and 650Nm but even the usually circumspect AMG boss Tobias Moers admits it’s capable of producing substantially more. As it is, the new AMG sportscar can sprint 0-100km in just 3.8sec.

The ‘standard’ GT, which will go on sale after the GT S (and a GT3 racing version of the car is now confirmed), is no slouch either. Its numbers are 340kW and 600Nm from the same 3982cc V8. It’s just two tenths of a second slower to 100km/h. If the GT’s 300km/h top-speed isn’t enough, the GT S is 10km/h faster.

The new 4.0-litre biturbo will also power the W205 version of the C 63, due for release early in 2015. In keeping with its race-ready persona, however, in the GT the hand-built engine is dry-sumped, allowing AMG to push it way back into the long nose. In conjunction with the engine-torque-tube-transaxle design the car also shares with the SLS, the GT S front-mid-engined layout delivers the same 47:53 front-to-rear static weight distribution.

The chassis of the two cars share DNA. Developed in-house by AMG, the SLS’s aluminium structure has been leveraged in the new car but it would be incorrect to say it’s a carry over. In creating the new shorter body-in-white for the GT S (its had 50mm trimmed from the wheelbase between the front axle and cabin firewall), AMG used existing raw castings and extruded sections from the SLS but they are reconfigured and uniquely machined.

Also all-new is the rear suspension design — a multi-link double-wishbone arrangement that plays a significant part in delivering the GT S better manners. The key change to the design is a more direct connection between the rear-wheel carrier hub and the damper itself. AMG says the redesign reduces wheel load fluctuations and delivers better camber control and rigidity.

Rear track is essentially the same as the SLS but the front of the GT S's footprint is 30mm narrower. This was in the main a product of the new car's styling rather than any significant engineering requirement.

Weight reduction was a focus in all of the re-engineering, however. With the gullwing doors also banished, the base GT is 100kg lighter than the SLS at 1540kg. Extra equipment in the GT S reduces the savings to 70kg.

On the GT S, damping is electronically controlled and adjustable on the fly — individually or as part of AMG’s Dynamic Select system which also tunes the hydraulic variable-ratio steering, throttle mapping, gearbox characteristics and stability and traction control functions across four preset modes (Comfort through Sport and Sport+ to Race).

The GT S also features a dynamic engine and transmission mounting system that’s new to AMG. For the record, Porsche has utilised a similar system on its sportscars for some years.

In the GT S four mounts (two on the engine and two on the transaxle), the rigidity of which can be altered using an electrical current, connect the engine-transaxle assembly to the body.

When ‘soft’, the mounts improve comfort as they provide “more effective decoupling of noise and vibration”. Says AMG: “Handling and agility benefit, however, from an overall stiffer mount set-up. Mercedes-AMG resolves these conflicting objectives using dynamic mounts, which adjust their stiffness continuously and instantly to the respective driving conditions and handling.”

Look for this tech to feature on more AMG models in the future — including the C 63.

And there are more changes — again reinforcing the fact that the GT S is not simply a re-engined shorter SLS. AMG has revised the internals of the transaxle, changing the gear ratios and improving the shift times and quality of the seven-speed dual-clutch AMG SPEEDSHIFT gearbox as well as installing a new electronically-controlled clutch-style limited-slip differential.

To again quote the AMG experts, this time on the E-diff: “The electronic function provides even more sensitive, faster control than the mechanical solution, thus pushing the limits of handling dynamics even further… The system operates with a variable locking effect in acceleration and overrun mode, and is perfectly tuned to the various driving conditions and road surface friction coefficients.”

After driving the new GT S in mainly damp-streaming wet conditions that’s one aspect of the performance for which we can vouch.

So too the blend of sensitivity and power the ceramic brake package fitted to the cars we drove at the Laguna Seca circuit in California. AMG offers the big 402mm/360mm carbon brakes as an option on the GT S and, cost aside, I can’t see why anyone would not tick the box. In the couple of dry laps I got on the track the stopping power was mega, aided also by the GT S’s better behaviour under hard stops (than its predecessor).

When the rain came down, the carbons offered good feel and feedback, something with which previous generations haven’t always obliged. For the record, the standard brake setup features floating alloy/cast iron 390mm front discs and 360mm rears — all gripped by multi-piston calipers.

Praise too for the Michelin Pilot Super Sport II fitted to the test cars. They’re not the quietest tyre out there but it’s hard to fault their performance on the road or the track. Just factor in plenty of change for new rubber — there’s no front-to-backing possible on the GT S. Not only are the rear tyres wider than the front, they are also larger diameter — 265/35 ZR 19 versus 295/30 ZR 20.

The big wheels at each corner are very much part of the character of the GT S — the front overhang looks incredibly short which somehow emphasises how far the cabin is pushed rearwards. The rounded glasshouse also gives the car a very different feel to the SLS and the benefit is substantial headroom in the cabin. Even tall drivers should be able to don a helmet for the odd track day.

The cabin itself is beautifully finished, but not beautiful… It’s a little too business-like for that. There’s the classic twin-tube instrument layout with simple binnacle and plenty of alloy and leather. The T-bar gearshift is so far rearward on the centre console you have to almost twist sideways to use it. It's an ergonomic glitch in my opinion but it means the various mode and drive-controls are closer to hand so it’s clearly intended to be that way.

The roof-hinged liftback is one of the very few uses of steel in the whole car. AMG says it's lighter in the ferrous metal than alloy. It covers a reasonably accommodating cargo area which has an aluminium cross strut that can be moved to secured your load.

Worth noting is AMG’s ability to leverage (nearly) the full suite of Mercedes safety goodies in the GT. Adaptive braking, attention assist, collision prevention, tyre-pressure monitoring, adaptive high beam, reversing camera and blind-spot assistance are all fitted. So too, the latest Comand Online infotainment system complete with 8.4-inch screen and a host of online functions.

Of course, none of this would mean a thing if the GT S didn’t deliver — on the road, and for many buyers, on the track. The good news is, as already hinted to above, the result of all of AMG’s development miles and SLS-based learnings is that the GT S is a cracker. Seriously fast but even more importantly, engaging and involving every step of the way.

The differences between it and the SLS are marked. The GT feels better balanced and has better power down, even despite the fact the bi-turbo engine has significantly more torque at almost all revs than the 6.2-litre naturally-aspirated V8 it effectively replaces.

At the same time, the GT S is more forgiving than the SLS. Overcook a corner entry, as you are want to do on an unfamiliar track like Laguna, and the GT S will let you know it’s not happy that you have both brakes and a little lock on but then it settles. The SLS in contrast did its best to slap you around the head and then continued to argue the point all the way until you wrestled it to towards the apex.

And at that point there’s another bonus that the GT S delivers — and not just at racetrack speeds but when driving on the road too. There’s a sharp, crispness to the way the front-end reacts to your inputs that isn’t present in many cars today. Point the GT S and it responds with a rapidity of movement that almost makes you think it initiated the manoeuvre on its own. It’s fresh, crisp and great to experience.

Even on the wet North Californian coastal ranges roads with leaf litter and the other detritus you’d expect, the GT S had excellent grip and was predictable in its responses. On these roads, when pushing on, the Sport+ settings on the dampers were a little too aggressive. No problem, using individual mode you’re able to tune the car to suit your needs.

In the end, for much of the 270km drive from San Francisco down to Monterey, we used the Comfort setting. The ride was good for a car of this ilk, maximising traction, and the gearbox was happier to let the engine hold taller gears so the torque could do the work. So driven, the GT S covers curvy miles very rapidly.

On the track, Sport+ and Race settings both retain some stability control assistance, the latter with a fair degree of sideways latitude. In these modes electronically controlled flaps in the exhaust allow the V8 to strut it stuff — who says turbos ruin exhaust notes?

Using the gearbox in manual mode it’s immediately apparent that it's here AMG has spent some serious development capital — the changes are quicker than before and, like the steering, reflect a sharper, more focused mechanical package. Even the steering wheel paddles’ movement feel different. There’s now a more precise, almost mechanical action to them. They’re a joy to use.

AMG’s own racers, and drivers faster than me, all admit the GT S is perhaps not as rapid in extremis as the ultimate versions of the SLS, but the differences are marginal. For the rest of us, our lap times would be faster and enjoyment level much higher in the new car.

The GT S is also a better car on the road. It’s also a hell of a lot easier to get in and out of!

Of course, the big question everybody wants answered is not how it performs compared to the SLS but whether the GT is a true 911 rival. I’ve got no qualms in answering…

Absolutely!

It’s a rival in the way it performs, the way it looks and the way it is the result of intense development focus from some of the smartest minds in the business.

Whether it’s better than the Carrera S, around which its pricing in the mid to high 200s will be targeted, is another question.

Porsches, and 911s especially, have an amazing ability to make a driver feel at home and at one with the car in just a few kilometres. The GT is a car that takes a fair bit longer to get to know.

With that in mind I’ll have to reserve my judgement. Not for ever — just until we can get the cars together. They both deserve that opportunity.