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Imagine the delight at AMG when parent company
Mercedes-Benz asked its in-house speed shop to develop,
for the first time in its history, a new engine from scratch.
What more could AMG's group of speed freaks, er,
engineers desire than that kind of unprecedented
freedom of action?
Apparently nothing, as the request resulted in a spectacular,
naturally aspirated 6208cc V-8 that should be regarded
as one of the great motors to ever come from the world's
oldest carmaker. Mercedes has found plenty of use for this
new V-8, from the slightly ridiculous (ML 63 AMG) to the
sublime (CLS 63 AMG), as it gradually replaces AMG's
much adored supercharged 5.5-liter V-8 in the stable. The
most recent application of this powerful race-bred engine, in
the stunning new CL 63 AMG, is the most impressive yet. If
there is a better blend of brawn and beauty in today's car
market, we have yet to see it. And if there is a better mix of
road control and luxurious comfort, we have yet to drive it.
Based on the S-Class sedan, but arguably much better
looking, the newly designed CL is at the leading edge of a
technological offensive in the ultra-luxury market.
Proliferation seems to be a key strategy in Mercedes' offensive,
as from this summer on, there will be four different CL
powerplants: a naturally aspirated 382-hp 5.5-liter V-8 in the
CL 550; a 510-hp 5.5-liter twin-turbo V-12 in the CL 600; a
518-hp 6.2-liter V-8 in the CL 63 AMG; and a slightly modified
604-hp twin-turbo V-12 in the upcoming CL 65 AMG.
Though two V-8s and two V-12s might seem overkill in
an ultra-expensive segment that generates a small percentage
of Mercedes' worldwide sales, AMG officials assure us
a different kind of buyer exists for each of these models.
The MSRP of the 2007 CL 550 and CL 600 is $100,675 and
$144,975, respectively. Although prices hadn't been
announced for the two new 2008-model coupes, expect the
CL 63 AMG to sticker for around $125,000 and the CL 65
AMG to command somewhere around $190,000.
Drivers who love g-forces will be happiest in the CL 63
AMG, engineered for those who want closer engagement
with the road than they might have in a typical luxury car. I
experienced those invigorating forces of gravity during a
swift downhill run from Kitzbuhel, Austria, to Munich, and
I can assure you they come from every angle: When you rip
open the envelope of massive power from the big V-8, slam
shut the 5,000-pound car's progress with the huge brakes, or
carve a sharp corner with the 20-inch low-profile Yokohama
rubber. Yet, for all the physical commotion caused by the
car's rapid descent from the Austrian Alps onto the Bavarian
plain, my passenger and I carried on the same conversation
we might have had over pretzels and beer, even after I
discovered how to disable the 155-mph speed limiter...
wait for it...the CL 63 can reach almost 190 mph without
much sturm und drang. I managed 180 mph before traffic
closed in at the end of an unlimited stretch of autobahn
south of Munich.
Mercedes says the big coupe can blast from 0 to 60 mph
in just 4.5 seconds, and I have no reason to doubt it. A big
jolt of torque pushes you back in the seat at just 2000 rpm
(I've owned cars that idled at higher revs) as 369 lb-ft are
directed to the rear wheels, but the car's sophisticated traction
electronics make even the swiftest full-throttle getaways
clean and stable. This V-8 doesn't have quite the level of
torque of the outgoing supercharged V-8, but it's still muscular
enough for to get entirely silly. Disable the traction
control, and the torque will make the rear tires shriek for
their lives-through five of the seven forward gears!
As with every AMG engine, the 6.2 is completely handassembled
by a single technician, but everything else in
this new powerplant is unique. It shares no parts or dimensions
with any other Mercedes-Benz engine, down to its
exclusive 109mm cylinder spacing, and many of its elements
were brewed from the competitive cauldron of
AMG's racing program.
Built from high-strength silicon-aluminum alloy, the
engine has, in classic racing fashion, a closed-deck aluminum
block with cast-in steel reinforcements and a highly
rigid "bedplate" design in place of individual main bearing
caps. Up top is a magnesium variable intake manifold, with
two electronically operated throttle flaps that open to max
flow within 100 milliseconds; four valves per cylinder
instead of the three-valve layout of previous Mercedes'V-
8s; and variable valve timing. Instead of rocker arms, bucket
followers are used to handle the increased stresses from the
ultra-stiff valvetrain. Big displacement requires lots of efficient
airflow to produce maximum power, so two 70mm
throttle bodies are used instead of the previous one. The
compression ratio is an improbably high 11.3:1, but detonation
is kept optimum by the electronics of Bosch's latest
engine-control system.
Optimum is how I generally felt about the entire car after
my four-hour romp to Munich. AMG doesn't just slap a
buffed motor into a car and leave it at that. Virtually every
support system gets the same attention to detail as does the
engine. For instance, the settings for the seven-speed transmission
and adaptive suspension are linked so that choosing
Comfort, Sport or Manual modes affects both the shift patterns
and chassis stiffness. When I was slaloming down the
immaculately paved, twisting two-lane roads of rural
Austria, I selected Manual mode and used the shift paddles
to work my around slower traffic (everyone else). The
CL 63 gets up to speed so quickly I had to remind myself
it's not a sports car, nor should it be driven like one.
I once got seriously into the huge brakes after being too
optimistic about my entry speed into a tight bend, but those
incredible binders brought everything under control with
barely a nudge from my right foot. Newly developed for this
car and the CL 65 AMG, they've got two sliding piston
calipers in front with huge 15.4-inch discs, and single-piston
floating calipers out back with 14.4-inch discs, and they stop
the CL 63 with calm assurance. Plus, essential in a car with
so much mass, they do it without upsetting the chassis' exquisite
balance. On rough surfaces, the Sport suspension setting,
which reduces body roll by an astonishing 95 percent, is a
severe compromise to a ride that in most conditions is eerily
smooth. Switch to Comfort mode, though, and an almost preternatural
calm descends upon the lavishly appointed cabin.
For more on this article and much more grab a copy of Auto Aficionado Magazine on newsstands nationwide!
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