This is the first all-AMG four-door saloon developed entirely in Affalterbach, and on account of that, the new 2019 Mercedes-AMG GT 4-Door needs to be rather good — Motormouth went for a test drive in Austin, Texas…
It’s been just over 50 years since a couple of former Mercedes-Benz engineers started tinkering away with racing engines. Hans Werner Aufrecht and Erhard Melcher couldn’t have known how far AMG would go, but in 1999 the Stuttgart manufacturer incorporated the famous Affalterbach tuning house as an in-house performance arm.
In all that time however there have been merely two fully AMG-developed vehicles — the SLS AMG ‘Gullwing’ built between 2010 and 2014, and the current Mercedes-AMG GT.
Now for only the third in-house development in its history, AMG has returned to where it all began with a monster four-door sports saloon it hopes will steal sales from the Porsche Panamera. The 2019 Mercedes-AMG GT 4-Door, though, is a far cry from the first modified Mercedes, a 300 SEL packing a 6.8-litre V8 that won its class in the 1971 Spa 24 Hours.
Rather than just a tweaked Mercedes-Benz production car, as the first four-door developed entirely in Affalterbach, it packs the GT Coupe’s 4.0-litre V8 twin-turbocharged engine, effectively replacing the CLS 63S, which is no longer being offered. The new 4-Door 63S is intended to be a saloon version of the brawny GT Coupe but it has more in common with the Mercedes E-Class than the race-bred sports car.
Remove the slick body and you will find the platform of the E-Class with the conventional front-mounted engine and transmission. The GT Coupe’s transaxle layout, incorporating the gearbox at the rear for better weight distribution, was deemed too complex to translate to the four-door, and too wide (by 136mm at the rear) to squeeze under the narrower saloon bodywork.
There are benefits, however — the 4-Door gains the latest Mercedes-AMG rear suspension mods including rear-axle steering. In this set-up, the rear wheels steer opposite to the front at up to 100km/h to reduce the turning circle of the five-metre long car and then turn in the same direction as the fronts for easier high-speed lane changing.
We’re testing the all-wheel drive 4-Door 63S on the Circuit Of the Americas in Austin, Texas, which is one of the best motor racing tracks you will find — fast, flowing, and dangerous if anything goes wrong.
Moments after yet another 255km/h run down the straight and punishing the six-piston, 360mm composite brakes of the 63S into Turn One, I’m following a driver who gets it crossed up as he exits. Turns One to Five flow in a series of downhill esses so if you get it wrong at the top it only gets worse as you try to regain control. From my position, I can see AMG’s electronic stability control saving him potentially from a high-speed off.
The evidence — graphic and re-assuring at the same time — is the small puff of brake dust from each wheel as the on-board computers wrestle the car back under control in micro-seconds without the driver even realising what’s happening. It would be reasonable to expect the rear end to get light through the constantly changing fourth-gear sweepers but it stays pinned the whole time.
The V8, rated at 639 horsepower and 900Nm, is easily up to the circuit task but the nine-speed auto transmission reminds me that this is still more of a road car than a track day special.
Smooth and quick on the up changes, the transmission is hesitant to accept quick, multiple downshifts when flicking the paddle-shifters back from fifth to second for tight corners. On the road, it performs seamlessly but it’s an example of the compromise facing the engineers when trying to graft AMG’s track-focused performance into a family-friendly saloon.
The interior is familiar, with the dash dominated by a digital wide-screen, and lots of black Nappa leather plus an Alcantara-wrapped steering wheel. Rear seating options include a bench for three, two seats with attached leather console, and two individual seats with an LCD control panel between them. Eight switches in the centre console around the gear selector operate the drive modes, traction control and exhaust modes, and the noise button is likely to get most use.
And that’s what AMG has done with the GT 4-Door — you won’t be able to resist firing up the exhausts every once in a while rolling out of the neighbourhood in the morning, because even though it’s no GT Coupe, the saloon strikes a great balance between raucous and responsible.
2019 Mercedes-AMG GT 4-Door 63S
4.0-litre V8 twin-turbo | 639 horsepower and 900Nm of torque | nine-speed automatic transmission, all-wheel drive | zero to 100km’h in 3.2 seconds and a top speed of 315km/h | approximately AED600,000