As we floored the accelerator in the Mercedes-Benz SLR
McLaren, there was a brief snap of wheelspin before the electronic stability
control stepped in to balance the sudden tidal wave of torque against the grip
of the car's 295/30ZR-19 rear Michelins. After that it was just a matter of
listening to the deep staccato beat of the 5.4-liter supercharged V-8 hurtling
the SLR down the relatively short runway at Malmsheim, near Stuttgart (where
Mercedes organized this performance test for American magazines), and then
tapping the shift button on the steering wheel each time the tach reached for
its 7000-rpm redline.
Do that with any degree of proficiency, and you are rewarded
with 0-to-60-mph sprints in just 3.6 seconds. The quarter-mile is dispatched in
11.6 seconds at 125 mph, and even that result might improve on a warmer
surface. C/D's test session was the last of four and took place in the
late afternoon, when October temperatures were on the decline.
Skilled testers can equal the launch performance of the
SLR's stability-control system (ESP in Mercedes-speak) by switching to its second,
less intrusive position and finessing the gas pedal for traction, but they
can't beat it. In the normal ESP mode, you have very effective launch control,
and since the SLR has 575 pound-feet of torque from 3250 rpm, that system is
worth its weight in gold-plated connectors. It was also reassuring to know that
the huge ceramic brake rotors and equally substantial calipers would quickly
slough off speed at the end of each 130-mph run on the relatively short
Malmsheim airstrip.
Dig into the loud pedal any time out on the road, and you'll
be gob-smacked by the sheer ferocity of the AMG engine's response. It might
involve a downshift to do it, but a big dig at the throttle produces the kind
of thrust that had everyone in our group shaking their heads in awe. Just check
out our 30-to-50 and 50-to-70 times, which at 1.7 and 2.4 seconds are the best
pair of top-gear acceleration times we've ever recorded for a production car.
In any situation other than a dry day on a straight road, a
deep prod at the throttle will likely be answered by the activities of both
engine andelectronic watchdogs. The engine wants to give its all while the
electronic systems are trying to save your life. Even then, we had a couple of
occasions in traffic when a stab at the pedal produced a brief twitch of the
tail.
That explains why Mercedes will not allow the ESP to be
switched off completely. In fact, while we were pondering this strategy during
a break at the test session, someone asked why one even needs 617
horsepower in a streetgoing car. The answer came from another writer: "To
reach 207 mph."
Exactly. If a company with a long motorsports history wants
to flaunt its heritage in a car that evokes both the 300SLR of old and the
Formula 1 McLaren of right now, it needs to breech the 200-mph mark in the same
way Ferrari's Enzo does. To push a big car like the SLR through an increasingly
resistant atmosphere to the 200-mph mark-particularly when it has a flat
bottom, front and rear diffusers, and a tail spoiler designed to provide downforce
at speed-you need big horsepower.
Mercedes performance partner AMG knows where to find it. AMG
knows how to package it, too. Looking at a fully dressed AMG SLR engine, one
can readily appreciate the unit's compact size. The 5.4-liter V-8 in the SLR
wears single-overhead-cam three-valve heads that are remarkably compact. The
twin-screw blower resides in the valley between the cylinder banks, where it
takes up very little space. A dry-sump lubrication system allows the V-8 to be
housed lower than with a conventional oil pan.
Even the side-pipe exhaust system, with its vertical
mufflers, helps keep the mass centralized. The engine sits comfortably
amidships, well behind the front axle line, and contributes to the car's nearly
perfect weight distribution. That lends the SLR some special handling benefits,
including a front end that hangs on well after you expect understeer and a
chassis that accepts additional steering lock in mid-bend without complaint.
Indeed, the SLR pulls an impressive 0.97 g on the skidpad, despite tires that
appear to be, at least on paper, less generous than what Dodge might apply to a
mere 500-hp car.
Turns out the Michelin Pilot Sport PS2 hoops specially
constructed for this car work exceptionally well, given their rain-or-shine
duty brief. The car does not offer particularly strong feedback at slow to
middling speeds, but it steps up the information flow when it begins to work
hard, lending confidence to the driver for further dynamic exploration. The
only problem here is that you're already traveling at high speed when the car
comes truly alive in your hands.
Don't be misled. The SLR has less of the syrupy layer than
most normal Benzes exhibit. Its steering is much more direct, as are throttle
response and all ride sensations. But the ride is pretty cushy as 200-mph
supercars go, and there is a thin gasket of luxury between mechanicals and
nerve endings, all of which was intentional. The car, we were told repeatedly,
was always envisioned as a fast GT. And that would explain the generous trunk
space compared with other cars of the genre, the three interior storage
compartments, the automatic climate control, the high-end stereo system, and
the custom-fit leather seats. (Cushions of various thicknesses are fixed to the
carbon-fiber seat shells to tailor each owner's fit to this $455,500 rocket.)
Therein lies the great paradox. Mercedes has tried to balance
the SLR somewhere between all-out supercar and civilized grand tourer. This
within a swoopy carbon-fiber monocoque chassis that has an unequal-length
control-arm suspension at all corners, gullwing doors, an active rear
airbrake/spoiler, side-pipe exhausts, and an engine that expresses power with
every revolution. Yet all these sporty flourishes are in combination with an
automatic transmission, various and sundry luxury trappings, and a substantial
3858-pound curb weight.
Clearly, this is a vehicle intended for a flexible role.
Luckily for us (and owners with the means), technology allows car designers a
lot of leeway these days, enabling less compromise than was possible just a few
years ago. A smooth ride and precise handling are no longer mutually exclusive;
nor are creature comforts and high power. You can indeed have your cake and eat
it, too.
This particular slice of cake has been very carefully baked.
According to Le Mans winner Klaus Ludwig, one example of meticulous development
is that the windshield wipers on the SLR work at 200 mph. Just what one might
be doing at 200 mph in the rain is anyone's guess, but it's nice to know that
this limited-production GT has had all its systems thoroughly checked out. At a
price that verges on half-a-million bucks--and an output of just 3500 SLRs over
the next seven years--we expect nothing less.
source: http://www.caranddriver.com/reviews/mercedes-benz-slr-mclaren-road-test-driving-impression-page-2January 2005
by Barry Winfield
http://www.boscheuropean.com
No comments:
Post a Comment