Theres been a lotta talk on internet chatrooms lately about whether the new AMG 6.2-liter naturally aspirated V-8 engine is an improvement over the supercharged 5.4-liter V-8 that was an AMG staple -- particularly, if the new car is quicker or slower off the mark. Well, the answer is yes and no, at least on the evidence of the CLS63 AMG that we have been stylin in of late. The 6.2-liter V-8 makes 507 horsepower in the CLS, up from 469 hp in the old CLS55 AMG. Torque is down, though, from 516 pound-feet to 465 lb-ft. More power usually results in better top-end performance, whereas more torque normally means quicker mid-range and off-the-line acceleration.
To a certain extent, thats what our numbers show. The CLS63 gets to 60 mph from rest in a blistering 4.1 seconds, a tenth quicker than the CLS55, but is identical otherwise up to 120 mph and shares a 12.6-second quarter-mile time. The 30-to-50 and 50-to-70-mph figures show the benefits of the supercharged motors fatter torque curve (2.2 and 2.5 seconds, respectively, compared with 2.5 and 3.1 for the CLS63), while the extra top-end grunt of the 63 comes into play above 120 mph. By 150 mph, the CLS63 is ahead by almost a second and a half.
So, apart from marginally better performance away from a stop light and in go-to-jail-fast territory, what are the benefits of the new engine? Well, it sounds absolutely fantastic, especially as it nears the 7200-rpm redline. (Yeah, thats right: a 6.2 liter V-8 that spins past seven grand.) The loud, guttural growl is a bit too intoxicating, because the desire to hear a blaring soundtrack makes it all too easy to stray into triple-digit temptation. It really does pickup and go past 100 mph.
The seven-speed automatic transmission is as smooth as a luxury-car salesperson, not to say that the old five-speeder was bad. More important, manual shifting is now effected by a pair of paddles on the back of the steering wheel -- right for upshifts, left for down -- in place of the buttons in the CLS55.
Other important mechanical changes are fitment of AMGs new sport suspension and revised brakes. The vented and cross-drilled front rotors are now 14.2 inches in diameter (up from 14.0 inches) and the front calipers have six instead of eight pistons. At the back, there are 13.0-inch-diameter discs and four-piston calipers. The AMG suspension is a recalibrated version of Mercedes Airmatic air-spring setup, which works in conjunction with the so-called Adaptive Damping System. Just like the system in the E-class, it has driver selectable settings, none of which are perfect. The sportiest setting beats you up over bad pavement and the comfiest one doesnt offer enough body control.
Still, the CLS63 has lots of grip, decent steering, and is very entertaining once the traction control is turned off and the throttle is mashed. It isnt quite as sweet a chassis as a BMW M5s, but the CLS has the advantage of a fine automatic transmission in place of the M5s clunky Sequential Manual Gearbox and a torquier, more compelling engine. Only serious AMG-heads are going to be able to spot the difference between this one and the CLS55. Discreet 6.3 AMG badges on the flanks and tail are the only real external clues, while there is a new instrument cluster and a fabulous, race-car-like steering wheel. Otherwise, the gorgeous CLS shape and lush interior remain. Why mess with success?
The only real drawback of this car is the sticker: $95,575 base, with an as-tested price of $100,805. Its a lot of dough, sure, but the combination of the CLS shape and the rocking new AMG powertrain make this is a sweet ride for the whizkids of this world.
Vehicle type: front-engine, rear-wheel-drive, 4-passenger, 4-door sedan
Price as tested: $100,805 (base price: $95,575)
Engine type: DOHC 32-valve V-8, aluminum block and heads, port fuel injection
Displacement: 379 cu in, 6208cc
Power (SAE net): 507 bhp @ 6800 rpm
Torque (SAE net): 465 lb-ft @ 5200 rpm
Transmission: 7-speed automatic with manumatic shifting
Wheelbase: 112.4 in
Length/width/height: 194.0/73.7/54.7 in
Curb weight: 4366 lb
Zero to 60 mph: 4.1 sec
Zero to 100 mph: 9.8 sec
Zero to 150 mph: 23.5 sec
Street start, 560 mph: 4.4 sec
Standing ¼-mile: 12.6 sec @ 114 mph
Top speed (governor limited): 158 mph
Braking, 700 mph: 163 ft
Roadholding, 300-ft-dia skidpad: 0.87 g
EPA fuel economy, city/highway: 13/20 mpg
C/D-observed fuel economy: 13 mpg