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.
Speaking of stops, the CL63 also incorporates an auto stop-start function-the first appearance of this technology in a non-hybrid Mercedes. Expect this feature to spread in step with the 5.5-liter bi-turbo. It would seem to offer significant city fuel-economy benefits, but we're told its effects don't show up in EPA testing (EPA numbers aren't available at this writing but should be out soon; Mercedes claims the new powertrain overall is 25 percent more efficient than its predecessor).
V-12s still come, to those who wait
Given the enhanced capabilities of the V-8s, the V-12 engines might seem superfluous-and they are, but both V-12 models return nonetheless. The CL600 has the same bi-turbo 5.5-liter twelve as before. It 510 hp is no better than the CL63, and its 612 pound-feet can't equal the performance-enhanced version of the V-8 AMG. The CL65 AMG, meanwhile, retains its 6.0-liter turbo V-12. Now with 621 hp, up from 604 hp, and 738 pound-feet, it remains comfortably atop the pack (and ahead of the new Bentley Continental GT). But-what's this?- it can only tie the 0-60 time, and 186-mph top speed, of the CL63 with the optional performance pack. The CL65 continues to use a five-speed version of the Speedshift automatic, and neither of the V-12s gets the auto stop-start capability. The V-12 cars are available by customer-order only; expect four to six weeks delivery time.
Your choice: crazy fast or totally insane
With its new engine, the CL550 has largely closed the performance gap with its AMG counterpart. Where the previous CL550 needed 5.4 seconds to reach 60 mph, the new car zooms to 60 mph in 4.6 seconds. That puts it only 0.2 second behind the new CL63 (0.3 second behind the performance-enhanced version). What this means is that, when you bury the long-travel accelerator, either CL is instantly beamed to the bumper of the car ahead. With doubling or even tripling the speed limit within such easy reach, an onboard defense lawyer might be a worthwhile feature.
Although the CL63's blown 5.5-liter can out-muscle its big-block predecessor, don't expect the sharp staccato bark that we know -- and love -- from the 6.2-liter-and-Speedshift combo in E63 and the SL63 AMG. The CL's rumble is a much more subtle baritone.
The AMG car's auto stop-start function works well, restarting quickly enough not to impede take-off. But it's strange how the sudden silence at red lights actually calls attention to itself. Expect in-car conversation to stop as well. The auto-stop feature only works if the transmission is in the C mode (which also makes for quicker upshifts and second-gear starts); it's disabled when the transmission is in Sport or Manual mode.
The CL550 uses air springs, while the CL63 (and the V-12 cars) adds active body control. Both coupes are a bit stiff-legged over bad pavement, the CL63 perhaps slightly more so, and choosing ABC sport or normal mode doesn't seem to make much difference. But the upside is that the CL-and particularly the AMG-exhibits iron-fisted body control. The CL63 has essentially no body roll, and for such a heavy machine (some 4800 pounds) it's also amazingly resistant to understeer.
An Invisible Hand directs the CL, for drivers who can't be bothered to do so themselves
The CL pioneered many of Mercedes' current high-tech features, from stability control (S600, 1995) to active body control (1999), so of course there is a full complement of high-tech features on board here. For 2011, the CL adds a new capability to the previous lane-departure and blind-spot warning systems. If the driver ignores either system's warnings, the car will automatically apply the brakes on the wheels on the opposite side, to nudge the CL back into its lane. Those systems, along with pre-collision braking, are part of the Driver Assistance Package (which maybe should be called the Distracted Driver Package); it's standard on the V-12 cars and optional on the CL550 and CL63.
Other technological wonders are less Orwellian and more entertaining. An optional split-view Comand screen allows a front-seat passenger to watch a DVD while the driver sees the navigation map, for instance. And the electronic gauge cluster in the AMG cars can call up a lap timer function.
Price? If you have to ask...
Despite a new front clip and a revised rear end (bumper and taillights), the overall look of the big Benz coupe is changed only subtly. Its signature element remains the arced roofline, set off by the B-pillarless greenhouse (which also nicely opens up the interior). In this rarified atmosphere, competitors are thin on the ground. No other car company does a two-door off of their large luxury sedan. The next-closest competitors might be the BMW 6-series (currently on hiatus), and the Continental GT, which has undergone its own, similar update this year.
The twelve-cylinder Benz coupes bracket the Bentley in price, with the CL600 at $157,875 and the CL65 AMG reaching $210,175. The CL63 is $151,125, while the CL550 is the bargain of the bunch at $114,025. Any one of them is a singularly self-indulgent machine.
2011 Mercedes-Benz CL550/CL63 AMG
BASE PRICE: $114,025/$151,125
ENGINE: 48-valve DOHC twin-turbo V-8
DISPLACEMENT: 4.7 liters
HORSEPOWER: 429 hp @ 5250 rpm
TORQUE: 516 lb-ft @ 1800 rpm
ENGINE: 48-valve DOHC twin-turbo V-8
HORSEPOWER: 536/563 hp @ 5500 rpm
TORQUE: 590/664 lb-ft @ 2000 rpm
TRANSMISSION: 7-speed automatic
DRIVE: 4-wheel (CL550), rear-wheel (CL63)
STEERING: Speed-sensitive, power-assisted rack-and-pinion
SUSPENSION, FRONT: Multi-link, air springs (active dampers, CL63)
SUSPENSION, REAR: Multi-link, air springs (active dampers, CL63)
BRAKES: Vented disc, ABS
L x W x H: 200.6/201 x 73.7 x 55.8/56.2 in
WHEELBASE: 116.3 in
TRACK F/R: 63.0/63.3 in
WEIGHT: 4619/4806 lb
FUEL MILEAGE: 15/22, 15/21 (est.)