Taming the Beast from the Green Hell
It’s a helluva green. Actually, it’s called Green Hell Magno, and it’s the signature color of the 2018 Mercedes-AMG GT R: the hottest, fastest, loudest machine in Daimler’s rapidly growing lineup of Porsche 911-fighting sports cars. It’s a not so subtle nod to the GT R’s birthplace, the fearsome Nürburgring Nordschleife, a 12.9-mile, 73-turn racetrack that swoops and sweeps through the heavily forested Eifel mountains in Germany. A racetrack nicknamed “The Green Hell.”
The people at AMG have a sense of humor. They call the GT R “the Beast from the Green Hell.” And yes, in Sport+ and Race modes it roars and snarls like an angry monster when you nail the throttle. The explosions from the exhaust when you lift off suggest you’re about to be overrun by an artillery barrage. Beyond that thundering wall of sound, though, is a carefully engineered sports car that’s crushingly fast, impressively agile, and very well mannered. But “the Scholar Athlete from the Green Hell” doesn’t make a good clickbait headline.
The GT R is the spearhead of the AMG GT family. “We put everything into this car,” AMG boss Tobias Moers says. “We invested all our heart and soul into it.” And more than a little of AMG’s race car expertise, too.
Developing 577 hp at 6,250 rpm and 516 lb-ft of torque available between 1,900 rpm and 5,500 rpm, the GT R’s engine is another iteration of AMG’s versatile 4.0-liter twin-turbo V-8. It develops 74 more horses and 37 lb-ft more torque than the version that powers our 2015 Best Driver’s Car, the GT S. That’s because new turbochargers have allowed maximum boost pressure to be increased from 17.4 psi to 19.5 psi, plus revisions to the combustion chambers, exhaust ports, and throttle mapping. The flywheel is 1.5 pounds (0.7 kg) lighter, reducing inertia and allowing the engine to rev harder, faster.
AMG’s seven-speed dual-clutch automated manual transmission, mounted between the rear wheels, is connected to the engine by a carbon-fiber torque tube that is 40 percent lighter than the cast aluminum unit used in regular GT models. The GT R’s transmission ratios are also more closely stacked. First is longer and seventh is shorter. The final drive ratio is also shorter. AMG claims the GT R will sprint to 60 mph in less than 3.5 seconds, which seems conservative given the 3.2-second time posted by the 33-pound heavier GT S during our testing. Claimed top speed is a whisker under 200 mph (321.9 km/h).
The coil-over suspension with AMG Ride Control adaptive shocks, which offer continuously variable damping rates, has been developed specifically for the GT R. The front track is wider, pumping out the front fenders almost an inch each side compared with the GT S, and the steering ratio has been sharpened. But the substantive changes are all at the rear end. Here, the track has also been widened, race car–style uniball spherical bearings that eliminate movement under load have been fitted, and the rear anti-roll bar is also thicker. But the biggest change is the adoption of a rear-steer system, the first ever fitted to a Mercedes production car. Two electronically controlled steering actuators replace the conventional control arms and can change the toe angle of the rear wheels by up to 1.5 degrees. Up to 62 mph (99.8 km/h), the rear wheels are steered in the opposite direction to the fronts in order to improve agility. Over 62 mph, they are steered in the same direction to improve stability.
This combination of agility and stability is the first thing you notice when hot-lapping the GT R. Compared with the GT S, the front end feels much more alert, responsive, and communicative into a corner. But Moers says it’s the back axle that’s really making it all work. Stability under braking is stunning. On the challenging Autódromo Internacional do Algarve in Portimão, Portugal, in GT Rs with the optional carbon-ceramic brakes, you could simply grenade the pedal on the downhill entry into the right-hander at the end of the main straight and keep hard on the brakes almost up to the apex of the corner. The back end tracked faithfully all the way into the turn.
The rear-wheel steering is just part of a sophisticated ecosystem designed to enable drivers to get the most out of the GT R. Airflow at the front of the car is carefully managed by an active aerodynamics system that lowers a carbon-fiber element 1.5 inches into the airstream at speeds above 50 mph (80.5 km/h) in Race mode and 75 mph (120.7 km/h) in the other modes to reduce front axle lift by up to 88 pounds (39.9 kg) at 155 mph (249.5 km/h). When the element is extended, the radiator air outlet is opened and guides airflow to the double diffuser at the rear of the car. Vertical louvers in the front apron are closed at high speeds but open in low speed corners to help cool critical components.
The GT R comes equipped with the usual menu of AMG drive modes—Individual, Comfort, Sport, Sport+, and Race—and each does pretty much the same as they do on other AMG cars in terms of changing steering response, throttle mapping, transmission shift protocols, damping rates, etc. But it also comes with a technology lifted straight from the GT3 race version of the car—nine-stage adjustable traction control, adjustable via a bright yellow rotary controller at the center of the dash.
Designed for track driving, it’s easily accessed (take note, General Motors): Simply select Race mode, and switch stability control off. The system immediately defaults to a midrange setting. Twist the knob to the right if you want more intervention from the traction control and to the left if you want less. At Portimão, AMG hot-shoe Bernd Schneider, a former Formula 1 driver and multiple DTM champion, opted for just one click’s less intervention than the default mode for a couple of no-holds-barred hot laps at Portimão.
Acceleration, steering, braking, chassis balance: In every way the AMG GT R is noticeably more precise, more responsive, more athletic on the track than the GT S. The Michelin Pilot Sport Cup 2 tires—275/35ZR19 up front and 325/30ZR20 at the rear—offer astounding grip, especially through fast corners. The GT R is very easy to drive quickly. But it does have its foibles.
From behind the wheel, the AMG coupe feels a big car, much bigger than a Porsche 911. You aim the thing into corners over that long hood, the front wheels way off into the distance. There is not quite the delicacy of feedback you get from a 911, either, and although the dual-clutch transmission is adept at serving the gear you want, when you want it, particularly in Race mode, it’s still not quite as sharply intuitive as the new 911’s PDK transmission.
The GT R’s chassis, like nature, abhors a vacuum: If you’re not on the brakes, it wants you to be on the throttle—even lightly—to feel absolutely balanced. And although it tracks straight and true into corners, there’s so much instant-on torque that you have to learn to roll on the gas to avoid lighting up the rear tires. Regardless of traction control settings, a fast lap in the GT R becomes an exercise in managing corner exit slip angles, and with your backside close to the rear axle, you feel every slight yaw motion, which takes a little getting used to.
Get dialled in to the GT R, though, learn to exploit the fabulous grip, the brilliant stability under brakes, and work the power delivery out the corners, and it’s an exhilarating drive. Front-engine, V-8, rear-drive: It’s like a Shelby Cobra, digitally remastered for the 21st century.
For all its chops on the track, the GT R is surprisingly comfortable on the road. In Comfort or Sport modes, the ride doesn’t feel noticeably harsher than that of the GT S. Sport seems the best all-round mode, delivering sharper responses from the powertrain and a decent ride without the gut-rumbling shock and awe soundtrack from the exhaust. It’s still a hardcore sports car, though, and coarse surfaces excite plenty of tire roar. You can order a GT R with a high-end Burmester sound system if you want, but you’d be better off putting the money toward the carbon-ceramic brakes and a bunch of track day tickets.
Mercedes-Benz USA has yet to confirm final numbers, but it says the GT R’s base sticker will be under $200,000 USD when it goes on sale Stateside next summer, pricing that puts it wheel-to-wheel with the Porsche 911 GT3 or Turbo S. Foolishness? Or confidence? Tobias Moers smiles and points out the GT R turned a 7-minute, 10.9-second-lap in the Green Hell, a comfortably quicker time than any 911 has managed. “I got a lot of text messages after that came out,” he says. “The Porsche guys are waking up.”
The Science of Speed: Detail stuff that makes the GT R fast
The redesigned exhaust system is 13.2 pounds (6 kg) lighter than that of the GT S, thanks to thin-walled stainless steel pipes and a muffler made from titanium. The GT R also features two central exhaust outlets and two on each side, with infinitely variable flaps that quiet the exhaust note in Comfort and Sport modes.
The large rear wing is rigidly mounted the to the GT R’s hatch in order to provide additional downforce on the rear axle. The wing’s angle can be adjusted manually to increase or reduce maximum downforce, depending on track conditions. Combined with the active aero hardware up front and the aero-optimized floor, the wing helps the GT R develop 341pounds (154.7 kg) more downforce than a standard GT at top speed, and it does it with less drag.
Light Wheels and Brakes
Unique to the GT R, the forged alloy wheels—10×19 front and 12×20 rear—reduce overall weight, rotational inertia, and unsprung mass. The optional carbon-ceramic brakes save a total of 33 pounds (15 kg).
In addition to the carbon-fiber torque tube that connects the engine and transmission, the GT R’s front fenders, roof, engine bay, and internal cross braces are all made of the weight-saving material. The prop shaft inside the torque tube is also carbon fiber. Weighing less than 9 pounds (4.1 kg), it is about 50 percent lighter than a comparable steel shaft.
|2018 Mercedes-AMG GT R|
|BASE PRICE||$185,000 (est)|
|VEHICLE LAYOUT||Front-engine, RWD, 2-pass, 2-door coupe|
|ENGINE||4.0L/577-hp/516-lb/ft, DOHC 32-valve twin-turbo V-8|
|TRANSMISSION||7-speed dual clutch auto|
|CURB WEIGHT||3890 lb (mfr est)|
|LENGTH X WIDTH X HEIGHT||179.2 in x 79.0 in x 50.6 in|
|0-60 MPH||3.5 sec (mfr est)|
|EPA CITY/HWY/COMB FUEL ECON||N/A|