Guide: Mercedes-Benz C199 SLR McLaren 722 Edition
Background
The arrival of the C199 SLR in 2003 marked the end of a 40 year wait for Mercedes-Benz to produce a successor for the original W198 300 SL Gullwing and Roadster.
After the W198 went out of production in 1963, Mercedes decided to focus on maximising the sales potential of their SL line. Subsequent SLs were therefore designed for style, comfort and practicality, rather than the kind of out-and-out performance that the W198 had become renowned for.
In the decades that followed, Mercedes occasionally gave a glimpse of what a W198 replacement may have looked like. Most famous were the C111 research and development vehicles of the late 1960s / early 1970s. There was also the C112 concept of 1991.
When the Vision SLR Concept was unveiled at the Detroit Motor Show in April 1999, Mercedes were inundated with requests for customer copies, just as they had been with the C111 and C112.
However, on this occasion, Mercedes finally caved to customer demand and a production run was sanctioned.
What had changed?
Mercedes now had a the partner firm they needed to produce a run of several thousand state-of-the-art supercars: McLaren.
Mercedes and McLaren had been working together in F1 since 1995. The partnership yielded McLaren-Mercedes the 1998 F1 Constructors’ crown and back-to-back Drivers’ titles for Mika Hakkinen in 1998 and 1999.
In late 1999, Mercedes signed a deal that would see the SLR produced at the new McLaren Technology Centre in Woking. As part of the plan, Mercedes’ parent company, Daimler, purchased a 40% stake in McLaren during early 2000.
The production version of the SLR Coupe was unveiled on November 17th 2003. Mercedes announced an anticipated run of 3500 units, all of which would be left-hand drive.
Unfortunately, while the SLR was well-received, demand was a little subdued.
To drum up interest and satisfy those customers that wanted a more driver-focused machine, Mercedes sanctioned a run of 300 high performance specials: the 722 Edition.
Unveiled at the Paris Motor Show in September 2006, the 722 Edition was enhanced to offer improved output, a more dynamic chassis, further refined aerodynamics and a sportier interior.
The production run would comprise 150 Coupes and 150 Roadsters.
The 722 moniker was a reference to the number worn on the 1955 Mille Miglia-winning Mercedes 300 SLR driven by Stirling Moss and Denis Jenkinson. Moss and Jenkinson smashed the existing course record and set a time that was never bettered before the Mille Miglia was banned two years later.
Engine / Gearbox
At the heart of the new car was another supercharged 90° V8.
For the 722 Edition, Bosch re-mapped their ME-2.8.1 engine management to further increase output.
The power unit was also given a bright red intake tract to differentiate it from the standard motor.
Peak output went from 617bhp to 641bhp at an unchanged 6500rpm. The torque rating jumped from 575lb-ft to 605lb-ft at 4000rpm.
The hand-built Type M155.980 V8 used in the SLR was developed for Mercedes by AMG. It featured an all-alloy construction, single overhead camshafts and three valves per cylinder (two intake and one exhaust).
Displacement was 5439cc thanks to a bore and stroke of 97mm and 92mm respectively. The compression ratio was 8.8:1 and dry-sump lubrication was employed. A Teflon-coated IHI Lysholm twin-screw supercharger ran at 0.9 bar.
The engine was coupled to the same AMG Speedshift R five-speed automatic gearbox and dry single-plate clutch used in the standard SLR.
Two fully automatic modes were offered (Comfort and Sport) along with three different Manual settings (Sport, Supersport and Race). Each mode featured progressively shorter shift times than the one before.
In Manual mode, gear changes could be activated by buttons on the steering wheel or using the Touchshift lever on the transmission tunnel.
Chassis
The SLR’s carbonfibre reinforced plastic monocoque was unchanged in the transition to 722 trim.
Suspension was via aluminium double wishbones with coil springs and twin-tube gas-pressurised shock absorbers. A front anti-roll bar was fitted along with anti-dive and anti-squat geometry.
For the 722 Edition, Mercedes tweaked the steering and added shorter springs that were 15% stiffer. New aluminium-shelled Koni dampers replaced the steel-shelled Bilsteins used on the standard SLR.
The net result was ride height lowered by 10mm, increased directional stability and less weight.
New forged aluminium wheels further helped in the weight reduction department. They also allowed space for bigger brake discs.
The rims measured 19 x 9-inches at the front and 19 x 11.5-inches at the rear. Importantly, they enabled Mercedes to fit larger 390mm diameter front brake discs (up from 370mm). The rear brakes stayed at 360mm diameter.
Eight piston calipers were used at the front and four-piston calipers at the rear. As usual, carbon-ceramic discs were fitted all round.
The SLR’s Sensotronic Brake Control was a brake-by-wire system that employed anti-lock software and Brake Assist.
Traction control, electronic stability control, power steering and electronic tyre pressure monitoring were also standard equipment.
Dual aluminium fuel tanks with a combined capacity of 98-litres were installed above each side of the rear axle.
Bodywork
In addition to the 722 Edition’s handsome forged wheels, a number of other visual enhancements helped it stand out.
At the front was a deep carbonfibre chin spoiler.
To balance the extra downforce this created, the rear diffuser was suitably enlarged.
Similarly, the electronic rear spoiler deployed to a more aggressive angle than the standard car (15° as opposed to 10°).
Other special features included 722 badges on each front fender, red brake calipers and tinted lights.
Interior
Inside, the 722 Edition received a carbonfibre centre console complete with numbered plaque.
Alcantara and leather with red stitching was used throughout.
A 722 logo was embossed on the headrest of each bucket seat.
The steering wheel now came with an alcantara suede rim and redesigned aluminium shift paddles were added.
The 722’s instrumentation featured new red-ringed dials housed in the standard SLR binnacle. A large speedometer and rev counter were inset with an array of warning lights and digital read outs. The speedo and tach were flanked by smaller gauges for water temperature and fuel.
The carbonfibre centre console housed a pair of air vents, controls for the transmission modes and the air-conditioning switchgear. There was also a flip-up SLR-branded panel that concealed the audio and satellite navigation systems.
The engine start button was under a cover on top of the gear lever.
The seats came with six-way power adjustment and custom-sized inserts in one of five sizes: Small, Medium, Large, XL or XXL.
Other standard equipment included dual-zone air-conditioning, a seven-speaker Bose audio system with six-disc CD autochanger, Bluetooth wireless connectivity, electric windows, heated electric mirrors, cruise control, six airbags, remote keyless entry and rain-sensing wipers.
Weight / Performance
Thanks to the various weight-saving measures employed, the 722 Coupe weighed in 44kg lighter than the standard SLR Coupe (1724kg as opposed to 1768kg).
The 0-62mph time was cut by two tenths of a second (down from 3.8 seconds to 3.6 seconds).
The 722 Edition’s 209mph top speed was 1mph faster than before.
Production Begins
Production of the 722 Edition Coupe began in August 2006.
722 Edition Roadster
Two years after the SLR 722 Edition Coupe had been displayed, Mercedes unveiled a Roadster variant at the Paris Motor Show in September 2008.
As per the Coupe, 150 Roadsters were built, all of which were left-hand drive.
The Roadster came with an electric canvas roof. Once manually unlocked from the front window frame and pushed upwards, the roof electronically folded away in under ten seconds. When lowered, it was concealed from view.
The Roadster was rated a tenth slower to 62mph (3.7 seconds compared to 3.6 seconds for the Coupe).
Top speed was a quoted 208mph which was just a 1mph deficit to the Coupe.
End of Production
Production continued until mid 2010.
722 Crown Edition
Of the 300 examples built, ten 722 Editions were commissioned by the King of Bahrain as gifts for fellow Arab royals.
Through the Mumtalakat Holding Company, the Kingdom of Bahrain had acquired 30% of the McLaren Group in January 2007.
All ten of these 722 Crown Edition cars were painted different colours and came with polished wheels.
Discrete Crown Edition badges were added on the front fenders and tailgate.
Text copyright: Supercar Nostalgia
Photo copyright: Mercedes-Benz - https://www.mercedes-benz.com
