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Mercedes-Benz SLR McLaren 722 Edition
1st February, 2007 | ||||
The new Mercedes-Benz SLR McLaren 722 Edition
displays thoroughbred motor-racing credentials. Featuring more than 300 modified
components, the super sports car serves up a boost in output, more dynamic
chassis tuning, improved aerodynamics and distinctly sporty interior
appointments to thrill even the most demanding of sports-car enthusiasts. The flawless roads which today lead through the desert next to Dubai are
ideal for demonstrating the pedigree sporting performance that characterises the
Mercedes-Benz SLR McLaren 722 Edition. Dubai is the up-and-coming business
centre of the United Arab Emirates (UAE). It is the setting for the world's most
ambitious construction projects, including the man-made "Palm Jumeirah" island,
and over the course of recent decades many wealthy sheikhs have become avid
automobile aficionados. It is this flair for the exceptional that links the
desert city on the Persian Gulf and its inhabitants with the Mercedes-Benz SLR
McLaren 722 Edition premium sports car. The new SLR 722 Edition model, though not available in Australia (owing to
the fact that production is in left hand drive only), evokes memories of a particularly special
victory achieved in 1955 by the British motor-racing legend Stirling Moss and
his co-pilot Dennis Jenkinson at Mille Miglia – the classic Italian endurance
race – behind the wheel of a Mercedes Benz 300 SLR with start number 722
(denoting the car's start time of 7.22 a.m.). Boasting an impressive output of
478 kW, the new SLR McLaren 722 Edition super sports car not only
outperforms its historic 'cousin', it even outstrips the scintillating peak
performance of the current SLR model. The new limited-edition series – only 150
models are being produced, for the most part handcrafted, at the McLaren Formula
1 works in Woking (England) – is the brand's response to calls from highly discerning SLR
customers for even more sportiness combined with the same high level of everyday
practicality. At the heart of the SLR 722 Edition is a 5.5-litre supercharged V8 assembled
by hand at the Mercedes-AMG engine workshops in Affalterbach, Germany, based on
the "One man, one engine" principle. Among the high-performance powerplant's
major strengths are its exceptionally spontaneous response to accelerator pedal
movements, high torque and that unmistakable V8 sound. Crankcase with dry-sump lubrication The powerplant's entire engine block with its enclosed crankcase sump is made
from cast aluminium. Each crankshaft is precision-weighted and revolves in five
bearings made from a high-durability material to enable sustained transmission
of the tremendous forces emanating from the supercharged engine. The forged pistons are only manufactured in extremely small numbers. Just
like the forged lightweight connecting rods, the pistons are measured and
weighed with utmost accuracy before being assigned to individual engines. This
keeps any mass balancing tolerances to an absolute minimum. The pistons slide
inside extremely durable, wear-resistant, low-friction cylinder barrels made
from a special compound which is otherwise only found in race car engines. Twin
oil injection is used for effective piston cooling. The oil cooling technology employed for the power unit as a whole also draws
on the brand's racetrack experience: a sophisticated dry-sump lubrication system
with a capacity of around eleven litres combines with a five-speed oil suction
pump and a two-speed oil pressure pump to guarantee reliable lubrication under
all driving conditions. One important knock-on effect of this dry-sump
lubrication technology, which is again normally exclusive to race cars, is that
the engine height can be kept low, allowing it to be installed deeper down in
the engine compartment: the result is a low centre of gravity that fosters
dynamic handling. Screw compressor power Efficient cylinder charging is the task of a belt-driven compressor with two
screw-shaped aluminium rotors that are Teflon-coated in the interests of keeping
friction low. In order to keep the engine running as efficiently as possible at
all times, the AMG engineers have devised an intelligent engine management
system which independently determines when to deploy the screw compressor as the
engine's rev speed and load change. Consequently, the supercharger is only
called into action when it is really needed. Notwithstanding this, however,
maximum power is always available the instant the driver summons it by opening
the throttle. Apart from the compressor, the engine's electronics monitor all of the other
variables which are relevant to its operation. At the same time, they ensure
optimum operation of the intercoolers' water circuit. After all, efficient
cooling of the charge air is a vital ingredient for high performance. The intercoolers operate based on the extremely efficient air-to-water heat
exchanger principle: the air which has been compressed by the compressor,
causing it to heat up, is directed through a separate water circuit to cool it
down again. This enables the eight-cylinder powerplant to maximise its output
and torque delivery. Manual transmission mode for shift times worthy of a race car High performance has also been ingrained into the five-speed automatic
transmission, which was developed in-house at Mercedes-Benz and has already
featured in a number of exceptionally powerful models. It has been optimised to
enable it to handle the awesome torque on tap and also offers drivers the
possibility of varying the gearshift characteristics. The transmission directs
the engine's power to the differential and the rear wheels via a precision
balanced drive train made from aluminium and steel. The interplay of the engine with the gearshift was also subject to
modification. For each of the individually selectable transmission modes – M
(Manual) and S (Sport) on the one hand and C (Comfort) on the other – there is
now a different accelerator pedal characteristic curve, which has been optimised
in line with the varying operating conditions. The end result is an extremely impressive set of performance figures, even by
high-end super sports car standards: the SLR 722 Edition completes the sprint
from 0 to 100 km/h in a breathtaking 3.6 seconds (SLR 3.8 seconds), with the
speedometer needle proceeding to pass the 200 km/h mark in a mere 10.2 seconds
(SLR 10.6 seconds) and the 300 km/h mark in just 28.0 seconds (SLR 28.8
seconds). Plus, the top speed of 337 km/h is even higher than that of the
current SLR (334 km/h). New chassis set-up for further enhanced handling dynamics One of the main driving forces behind the enhanced performance of the SLR 722
Edition is the retuned chassis. Development work at McLaren's Formula 1
headquarters was based on the set-up of the SLR's proven aluminium chassis, that
is itself the handiwork of experienced race car developers: wheel guidance is
the task of double wishbones at both the front and rear. The bottom links are
arranged in such a way that the wheels receive a negative camber when the
springs compress or when cornering at speed. This guarantees optimum contact
with the road in any situation. Meanwhile, the axle technology also minimises
the degree of diving and squatting while braking heavily and accelerating
respectively. The axle's wishbones are made from forged aluminium, while cast aluminium is
used for the wheel carriers. This lightweight material boasts a host of
advantages compared to conventional steel constructions, including the far
superior response of the suspension and damping resulting from the reduced
weight. The relatively long wheelbase of 2,700 millimetres likewise contributes to the
exemplary handling characteristics, with the most notable benefit being the
outstanding straight-line stability, while the wide track combines with the low
centre of gravity to enable high cornering speeds. The chassis construction has the anti-roll bar positioned above the front
axle where it is controlled via rocker arms, just like on a Formula 1 car. With
this set-up, the anti-roll bar does not take up any additional installation
space. In this way, the smooth lines of the underside of the vehicle are not
disrupted, which is vital for the sports car's outstanding aerodynamic
characteristics. In the first phase of chassis development for the Mercedes-Benz McLaren 722
Edition, various combinations of chassis parameters, such as springing and
damping, underwent a series of tests on the Formula 1 dynamometer in Woking.
Then the Mercedes-Benz and McLaren engineers made further refinements and
finalised the new set-up by performing an extensive series of tests on the road
and, above all, on the race track. The stiffer spring rates and shock absorber characteristics of the chassis as
well as the lowering of the body by 10 mm at both the front and rear are what
gives the SLR 722 Edition its increased directional stability and noticeably
further enhanced handling dynamics. Body roll on bends has been reduced by over
20 percent, allowing the new SLR 722 Edition to corner at even greater speeds. New 19-inch forged aluminium wheels also help to improve the handling
dynamics of the special-edition model, their unique, palladium grey design
highlighting the car's motor-racing heritage. Their lower weight compared to
conventional wheels reduces the unsprung masses, making the responsiveness of
the SLR 722 Edition all the sharper. Plus, the 19-inch wheels allow larger brake
discs with a diameter of 390 mm to be fitted on the front axle. Hailing from the
Italian manufacturer "Brembo", the new braking system combines with the
carbon-fibre-reinforced ceramic discs to provide formidable decelerating power
which is fully in keeping with the SLR 722 Edition's scintillating all-round
performance. Exhaustive testing was carried out to develop a new ESP® control
system for this new brake configuration. High-tech material for exemplary safety and maximum strength The high-performance sports car's bodyshell bristles with high tech. The
entire bodyshell, including the crash structures at the front and rear, the
occupant cell, the swing-wing doors and the bonnet, is made from
carbon-fibre-reinforced plastic (CRP). This lightweight yet, at the same time,
extremely rigid material is a technology borrowed from the aviation and space
travel industry and has already proven its worth in ultra-sophisticated Formula
1 race cars. Despite the weight-saving of 50 percent that this high-tech
material represents compared to steel, it is just as strong, which allowed the
engineers to focus on achieving the body's enormous strength. Plus, in the event of an impact, carbon fibres have a specific energy
absorption that is some four to five times higher than steel or aluminium.
Mercedes-Benz has capitalised on this material property by also fitting two
620-millimetre-long side member elements made from carbon fibre in the front
structure of the SLR 722 Edition; these are capable of absorbing all of the
impact energy in a head-on collision without exceeding the maximum levels of
deceleration that the occupants are able to withstand. In the event of an
impact, the fibres of these two elements tear from front to rear to crumple in a
carefully predetermined manner and thereby produce a constant rate of
deceleration. The super sports car's occupant cell is likewise made from this high-tech
material, offering passengers a very rigid and therefore safe survival space in
an accident. At the rear of the car, the task of absorbing energy in a crash
falls to two internal side members made from laminated carbon fibre and a sturdy
cross member, which together ensure that the occupant cell remains virtually
intact. The occupant protection system also encompasses adaptive front airbags,
which are deployed in two stages depending on the severity of the impact,
head/thorax bags and knee bags, as well as seat belt tensioners and belt force
limiters. An aerodynamic work of art: even more downforce and an improved cd figure Around 100 hours of meticulous work in the wind tunnel also helped boost the
performance of the SLR 722 Edition. Here the developers performed yet another
technical masterstroke by increasing downforce whilst at the same time reducing
the cd (drag coefficient) figure. It's all thanks to the air-splitter at the
front end of the SLR 722 Edition. Consisting of carbon with a clear-coat finish,
the distinctively shaped spoiler lip not only enhances aerodynamics, it also
increases the downforce at the front axle by 128 percent. Small wheel spoilers,
also finished in carbon, reduce air swirl at the rear axle, making for a
smoother airflow and optimising road feel. The spoilers combine with the
airbrake at the rear to produce a further substantial gain in the downforce
acting at the rear axle of the new SLR 722 Edition. The result is even more
precise handling and turn-in at high speeds. The rear-mounted airbrake is designed to optimise directional stability and
braking power: when the speed exceeds 120 km/h, it automatically rises up at an
angle that has been adjusted in line with the extremely dynamic performance of
the new model. If the driver hits the brakes hard at high speed, the airbrake
tilts up into the airstream automatically. This dynamic modification increases
rear-axle downforce within a fraction of a second, thus partially compensating
for the dynamic axle load distribution during braking, which presses towards the
front axle. A further factor which contributes to the distinctly sports-oriented
configuration is the weight of the SLR 722 Edition, which the engineers have
managed to reduce by around 44 kg. A lighter oil tank and damper bodies made
from aluminium, which have the added benefit of improving the vibration response
of the unsprung masses, contribute to this weight loss. Last but not least,
optimised panelling and insulating materials also have a positive effect on the
vehicle weight. Yet for all these measures, the high levels of comfort, safety
and practicality that have become Mercedes hallmarks remain unaffected. Sporty design through and through In terms of exterior design, the SLR 722 Edition features discreet sporty
touches, thereby satisfying the desires of keen gentleman drivers and affluent
sports-car collectors – the core target group – to the letter. The new-look
19-inch light-alloy wheels afford a perfect view of the red-painted brake
callipers and the large brake discs, emphasising the sheer power and performance
that underpins every aspect of the SLR 722 Edition. In addition, individual
components in carbon with a clear-coat finish highlight the close ties with
Formula 1. Plus, the grille-style design of the black-painted air outlets on the
bonnet, not to mention the front and rear light clusters with their palladium
grey surrounds, blend in perfectly with the carbon-fibre look. The SLR 722
Edition is available with a crystal antimony grey paint finish which creates a
vivid impression of depth and produces an extremely intensive-looking surface
structure. Moving inside, the sports bucket seats, upholstered in a combination of
semi-aniline leather and Alcantara, offer excellent lateral support, while the
colour contrast provided by the distinctive "300 SL red" stitching throughout
the interior, the 722 insignia on the head restraints and the red seat belts is
designed for added visual impact. The attractive material mix comprising
semi-aniline leather and Alcantara, which gives the interior its characteristic
look and feel, also features prominently on the roof lining and door panels.
Frequently used controls, such as the shift lever and handbrake lever, are
trimmed in easy-grip, moisture-absorbing suede. The sporty design philosophy
that is at the heart of the SLR 722 Edition is also reflected by the widespread
use of carbon throughout the interior. This material, straight from the world of
Formula 1, lends the centre console an extremely puristic look. The restyled instrument cluster focuses the driver's attention on the key
vehicle data, comprising classic-style round dials with a signal-red background.
The functionality of the multifunction display is given an extra sporty touch in
the form of the AMG RACETIMER. Finally, the designers paid special attention to
the steering wheel as the key link between driver and car: with its combined
leather/suede trim, the rim is extremely easy to grip and helps the driver to
stay in complete control when performing high-speed manoeuvres, as do the new
aluminium shift paddles. |
ABN 47106248033 |
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