Instrumented Test
The Mercedes-Benz SL has always been a wonderfully excessive machine, a symbol of personal success as much as a totem of German engineering. Long our choice among the modern folding-hardtop versions, the burly SL63 AMG gains even more power for 2015 as AMG endows its M157 twin-turbocharged 5.5-liter V-8 with the latest tuning.
The SL63 received its last major update for 2013, when it placed second to a Porsche 911 cabriolet in a four-car comparison test of high-performance luxury droptops. The highlights then were the SL63’s sportier demeanor, a significant weight savings, and the addition of the turbocharged V-8—good for 530 horsepower in standard trim and 557 with the optional AMG Performance package. That engine’s 664 lb-ft of torque still punishes the SL’s driveline from about 2000 rpm, but Mercedes has turned up the boost to a full 577 horses at 5500 revs, in line with the latest S63 coupe and sedan. (Most previous buyers opted for the uprated engine anyway, so there’s no longer a higher-performance option.)
The rest of the SL63’s mechanicals are largely the same, meaning giant carbon-ceramic brakes ($8950), a great balance of deft handling and ride quality, an engineering marvel of a folding metal roof, and AMG’s seven-speed automatic gearbox with a clutch pack in place of the torque converter. A bevy of settings for the transmission, suspension, and stability control all personalize the car’s attitude to the driver’s whim. Also the same, however, is the current SL’s blocky, overwrought nose, along with interior fixtures that are a bit stale next to the finery populating the latest Mercedes cabins.
At the test track, the stopping and handling figures of our 4101-pound test car were similar to those of the 2013 model. Yet, the more powerful SL63 actually lagged behind its predecessor’s mark of 3.6 seconds to 60 mph and 11.8 in the quarter-mile at 124 mph. While we were able to beat the AMG’s automated Race Start mode with a careful right foot, the best we could manage was four seconds flat to 60 and 12.3 in the quarter at 118 mph.
Varying grip levels at different testing locations likely accounted for part of the discrepancy (the previous model was tested in California, the 2015 car in Michigan), with the newer version proving extremely difficult to launch without excessive wheelspin. But the 2015 car also was slightly slower in passing maneuvers and rolling starts, where launch performance isn’t a factor. So the car may not have been performing to its full potential.
Like It Matters
Not that that should deter any potential buyers. The SL63 is magnificently quick on the open road, and listening to its snarling V-8 pulse with the top down is pure joy. This is still a lord of open-air motoring, with a regal price tag to match: $148,975 to start, or more than 40 grand above the gentlemanly SL550.
Our test car’s figure quickly ballooned with the carbon brakes, as well as carbon-fiber exterior trim ($3570), Designo white nappa leather upholstery ($3100), the electrochromatic Magic Sky Control roof ($2500), Night View Assist Plus ($2260), and several other gadgets and driver aids. Total: a properly lavish $172,755. Of course, if true excess is your thing, Mercedes will also sell you the 621-hp, V-12 SL65 AMG for $217,475.
