Mercedes AMG GT C Coupe 2018
Mercedes AMG GT C Coupe
Think of the new GT C that has been added to the Mercedes-AMG GT lineup as the equivalent of the Carrera GTS in the Porsche 911 roster. Both cars are the third step up on the power and expense ladder. Both come standard with distinctive interior and exterior design details. Both have fatter rear haunches to accommodate wider wheels and an increase in track compared with their lesser brethren. And both are topped by a track-oriented model further up the price and power scale—the GT R in the AMG’s case and the GT3 for the Porsche.
Mercedes AMG GT C Coupe:
Although AMG has copied the model structure that Porsche has successfully developed over more than 50 years of the 911, it does so with a completely different sort of car. The GT has its engine in the front rather than in the rear. That engine is a twin-turbocharged 4.0-liter V-8, not a twin-turbo 3.0-liter flat-six. And instead of the 911’s clean and classic lines, the GT snaps and crackles with visual firepower.
While not a retro design, the GT sports a rather lengthy hood by modern standards—one that recalls the 300SL from the 1950s. The same goes for the gaping new Mercedes grille inspired by the SLs that campaigned in the Carrera Panamericana, the coast-to-coast Mexican road race of the same era. With its beefy vertical bars that look like the teeth of some giant prehistoric catfish and the pie-sized three-pointed star centered in the opening, the grille dominates the appearance of this flamboyant car. The small, sleek greenhouse tacked onto the tail end of the body further emphasizes its muscular nature.
Mercedes AMG GT C Coupe:
What Makes a Mercedes AMG GT C Coupe
In this latest C variant of the GT, that muscularity is enhanced from the rear view by an increase in overall width from 76.3 to 79.0 inches. The wider bodywork accommodates a rear track increase of 1.7 inches, as well as 12.0-inch-wide rear wheels with 305/30ZR-20 tires instead of the 11-inchers with 295/30ZR-20s on the S. This wider bodywork and track are shared with the street-legal GT R track special—which just set the second-fastest time ever at our annual Lightning Lap showdown—although that model comes with even fatter rear tires.
The GT C’s engine also has more in common with the GT R’s than with the one in the base and S versions of the GT. Those two cars share a common turbocharger and intercooler package and have been uprated slightly for this year, with the base engine now developing 469 horsepower at 6000 rpm and 465 lb-ft of torque at 1700 rpm, while the S makes 515 ponies at 6250 and 494 lb-ft at 1800. The key difference is peak boost pressure—14.5 psi for the base engine and 16.0 for the S.
The slightly different version of the 4.0-liter V-8 in the C and the R is fitted with larger turbochargers to develop even higher boost pressure more efficiently. To help in this task, they employ freer-flowing exhaust ports, larger heat exchangers for the liquid-to-air intercoolers, and a reduced compression ratio—9.5:1 instead of 10.5:1 on the less powerful engines. Operating with a peak boost of 18.1 psi, the GT C engine produces 550 horsepower at 6750 rpm and 502 lb-ft at 1900 rpm. The R engine runs 19.6 psi to develop 577 horses at 6250 rpm and 516 lb-ft at 1900.
The seven-speed dual-clutch automatic transmission also comes in two versions to match these engines. The lower-powered cars get a wider-ratio gearbox coupled to a 3.67:1 final drive, while the C and R transmissions have a higher first and a lower seventh gear attached to a 3.88:1 rear end. That produces an overall ratio spread that’s about as close as that of the seven-speed dual-clutch in the 911 GT3. First gear is about 5 percent taller than in the standard AMG GT’s gearbox, second through sixth are 5 percent shorter, and seventh is almost 14 percent shorter. The C and R models also get standard electronically controlled engine and transaxle mounts to provide a better combination of comfort and precision than can be achieved with conventional mounts.