Five years after the current Mercedes-Benz CL coupe made its debut, the big two-door has gone in for some minor cosmetic surgery, and a heart transplant. Although their model designations have not changed, the CL550 and CL63 AMG both have new, smaller V-8 engines, but never fear, plutocrats, they're nonetheless significantly more powerful than their predecessors, thanks to the miracle of turbocharging.
It's turbo time for the V-8s
The CL550 engine has gone from 5.5 liters, with 382 hp and 391 pound-feet, to 4.7 liters, but twin turbochargers and direct injection help the new engine make more with less. Output jumps to 429 hp and torque increases by nearly a third, to 516 lb-ft. The additional power is sent through the same seven-speed automatic transmission and 4Matic all-wheel drive as before. As in 2010, the CL550 is the only one of the big Mercedes coupes to come with all-wheel drive.
The CL63 AMG's powertrain has been more extensively changed. It now uses a 5.5-liter version of the 90-degree CL550 V-8-also twin-turbocharged and direct injected. The new AMG V-8 eventually will replace the old 6.2-liter engine in all the "63" AMG models. (The S63 gets it this fall, concurrent with the CL63.)
That means AMG will have switched from supercharging, to normally aspirated power, and now to turbos. While the new bi-turbo V-8 strikes a blow for consistency, you can't argue with its output: 536 hp and 590 pound-feet, up from 518 hp and 465 pound-feet. Sound good? But wait, there's more. Opt for the AMG performance package, and the black boxes allow the engine to make 563 hp and 664 pound-feet; the package also raises the electronically limited top speed from 155 to 186 mph.
Auto stop-start debuts
The new AMG engine is paired with the seven-speed Speedshift gearbox, which uses a wet clutch in place of a torque converter. This is a revised version of the transmission currently in the SL63 and the E63. With a new clutch pack and reprogrammed software, the gearbox is better mannered here, not only whipping off super-quick gear changes and matching revs on downshifts, but now also equaling the smoothness of a torque-converter automatic when taking off from a stop.