Mercedes-Benz AMG GT revealed

AMG has fired two heavy-hitting shots in an extravagant push to replace its exclusive SLS with a more affordable junior supercar.

The official Mercedes-Benz hot house sprung a surprise by showing an even faster GT S version alongside the long-awaited, often-teased GT at its official global reveal at AMG's Affalterbach headquarters in Germany overnight.

With 375kW of power from its 4.0-litre twin-turbo V8, the front-engined GT S looks set to be an immediate rival for Porsche's classic 911 Turbo, even though it is strictly rear-wheel drive supercar.

Capable of bursting to 100km just 3.8 seconds, the GT S will be the clear-cut flagship of AMG, with a Dynamic Plus package on top of that for track-day regulars.

The GT S will have 35kW more power than the standard AMG GT, itself delivering a not-inconsiderable 340kW of power from the same 3982cc V8.

The second sports car designed and built completely in-house at AMG, the GT will be just two tenths of a second slower to 100km/h than the GT S.

Both AMG supercars will streak beyond 300km/h on a German autobahn, with the GT hitting 304km/h and the GT S claimed to eke that out to 310km/h. Both cars are sub-10L/100km efficiency contenders, with the GT a touch better with 9.2L/100km and 216g/km of CO2.

“With the new GT we are positioning Mercedes-AMG even more aggressively as a dynamic sports car brand,” Mercedes-AMG CEO Tobias Moers explained.

“With its technological substance, the GT fulfills our high aspirations with regard to driving dynamics, agility and sportiness.”

Unlike the SLS, the GT is intended to be a supercar that's as much about everyday practicality as it is about raw speed. It uses a roof-hinged liftback to cover its useful 350-litre cargo area, which can take two golf bags length- or cross-ways and it even has an aluminium cross strut to change the size of the luggage area to stop bags sliding around.

AMG claims its designers focused on the usability of the two-seat cabin. It has a classic two-tube instrument cluster for the tachometer and speedo, while aluminium shift paddles sit behind the leather-clad, flat-bottomed steering wheel.

It has four air-conditioning vents and a seven-inch multi-media screen dominates the central part of the dash, though this vaults to 8.4 inches if the optional Comand Online system is ordered. There is a pair of cupholders in the centre console, just ahead of a large central storage area, along with a full-sized glovebox.

To highlight the ties to its parent company, the GT is full of familiar Benz safety gizmos, too, including adaptive braking, attention assist, a collision prevention system that brakes the car automatically to avoid or minimise collisions if the driver doesn't, tyre-pressure monitoring setup, automatic parking, adaptive high beam, reversing camera and blind-spot assistance.

Daimler board member in charge of Research and Development, Dr Thomas Weber, insisted the GT was the kind of car AMG needed to cement its place in the high-performance world.

“With the new Mercedes-AMG GT, we are venturing out into a challenging sports car segment with its top-class competitive field,” Dr Weber explained.

“This is an incentive and motivation for us at the same time to prove to sports car enthusiasts around the world the kind of performance that AMG is capable of.”

Both of the GT models are based around a slightly cheaper development of the space-frame aluminium chassis that has already seen service in the SLS, with AMG claiming a 1540kg kerb weight for both cars.

The GT family sits its V8 engine up front, but well behind the front axle to be a nominal mid-engined car, while it carries a rear-biased 47/53 front/rear weight distribution.

More than 90 per cent of the chassis is aluminium and AMG has gone to such extremes to shift weight rearwards that the bootlid is made from steel while the front decking is magnesium. The result is a bodyshell that weighs just 231kg and is built for AMG by Mercedes-Benz at neighbouring Sindelfingen.

The GT family sends drive through a seven-speed dual-clutch transmission, built by Getrag, that is a development of the SLS unit and a direct relation to the gearbox in the LaFerrari. It is, unusually, located just ahead of the rear axle in a solid transaxle that includes the differential, largely for balance and stiffness reasons.

While the GT uses a conventional mechanical limited-slip differential, the GT S uses an electronically locking diff that AMG insists is faster and more reactive, creating better drive out of corners, more predictable braking behaviour and a finer ability to balance the car.

Benz has stepped forward to forged aluminium for the wishbones, the hub carriers and the steering knuckles for added rigidity and lower unsprung mass.

The GT has a fixed damping system, though it can also be ordered with the AMG Ride Control, fitted as standard on the GT S, which is basically an electronically controlled, active damping system.

It lets the driver choose from Comfort, Sport and Sport + options for the damping via a button that is separate from the similarly named powertrain settings.

AMG is claiming a big step forward in the variable-ratio steering system, which is speed-sensitive and changes its sensitivity depending on the lateral acceleration the driver is pushing through it.

The actual gripping-the-road part is done by 255/35 R19 front tyres and 295/35 R19 rears, mounted on forged alloy wheels and bolted to the car via double wishbones all round.

The GT S steps that up a notch with 265/35 R19 front tyres and 295/30 R20 rears, while the even faster Dynamic Plus option for the GT S specifies Michelin Pilot Sport Cup 2 rubber for the track junkies.

It slows the pace with 360mm discs at each corner, while the GT S adds 390mm front discs and there is a carbon-ceramic option, with monster 402mm front discs, as well.

But the highlight will be the engine, dubbed M178 in AMG's internal coding system. The new engine shares a lot of its architecture with the thumping 2.0-litre four-cylinder turbocharged motor in the A 45 and CLA 45 AMG, right down to its bore and stroke ratio and its direct-injection and variable valve timing systems.

With its turbochargers nestled inside the V8's vee and dry-sump lubrication, the engine sits low in the chassis and reaches its peak torque at just 1600rpm, then holds it until 5000rpm. Its peak power arrives at 6000rpm — identical to the more powerful GT S's peak — though the Dynamic Plus software broadens the power peak to spread it from 6000 to 6500rpm.

The fastest GT S has more torque, but its peak arrives 150 revs later. And if you are still looking for reasons not to stretch up to the GT S, it weighs another 30kg over the GT, partly because of its bigger brakes, wheels and tyres.