The red mist has just descended upon me, and that’s a good thing.
It’s my second four-lap stint in the 2019 Mercedes-AMG GT 63 S 4-Door Coupe on the Circuit of the Americas outside Austin, Texas, and four-time DTM champion Bernd Schneider is leading the way in an AMG GT-R. He just took off like a, well, like a four-time DTM champion. Pressed to keep up, I start to get sloppy. I charge a little too hard into corners, brake a little too late, and miss a few apexes.
Until now I basically thought this car was perfect. Now I get to find out what it does when pushed to its (and my) limits.
The AMG GT 4-Door Coupe (it’s not really a coupe; it’s a four-door hatchback) is no lightweight. Sized like an E-Class sedan or a Porsche Panamera, the big fastback weighs in at about 4,500 pounds. It shares its basic architecture with the E-Class and its derivative, the CLS-Class coupe-like sedan, but the body wears a unique design and AMG engineers have taken numerous measures to strengthen it. That work has paid off in a car that drives much smaller than its size and weight.
I’ve driven fatties on this track before and they want to run wide in the esses between turns 2 through 6, then plow forward in fits of understeer in the sharp left-right-left combo of turns 7, 8, and 9. Turns 7-9 especially tax the agility of a car, and during my first session, when I was going maybe 80 percent, the GT 4-Door Coupe wasn’t fazed. I was impressed.
Now, however, I’m driving at 90 and sometimes 101 percent of my capability, and the car’s weight is beginning to become apparent. Turn-in is still razor sharp—as long as I remember that, yes, you have to brake for turns if you want to keep pace with a German racing legend. The 14.1:1 steering ratio is fairly quick, the front end responds right now, and the variable ratio steering gets sharper the farther off center I turn the wheel. Any understeer I induce with my overzealous driving is easily remedied with a harder stab of the brake pedal, which triggers immense stopping power from the mammoth carbon ceramic brakes at all four corners—15.8-inch rotors up front with 6-piston calipers, 15.3-inch rotors out back with 4-piston calipers.
Long at a 199.2 inches overall, the GT’s rear end is willing to follow the front like that of a smaller car. Here the culprit is the standard rear-wheel steering system that can turn the rear wheels 2.5 degrees opposite of the fronts for added agility at speeds up to 62 mph. Above that speed, this system can also turn the rear wheels a half a degree with the fronts for stability.
A standard electronic limited-slip rear differential (eLSD) helps in turns and when coming out of them. It has a clutch that can send the power to the outside wheel for additional agility, and lock up to provide stability and traction for the massive 315 mm Michelin Pilot Sport 4Ss to bite into the pavement when flooring it for the straight.