Mercedes-Benz McLaren SLR 722 Edition

Are you telling me this beast has 722bhp under the bonnet? Not quite. The 722 – or the Mercedes-Benz McLaren SLR 722 Edition to quote its full name – is a limited run of tweaked SLRs, named after the Mercedes 300 SLR that British racing legend Stirling Moss and his co-driver Dennis Jenkinson drove to victory in the 1955 Mille Miglia race from Brescia to Rome and back.The number actually refers to the time - 07:22am - that they started the grueling 1000-mile race, and they completed it at a record-breaking average speed of 100mph.

Hmm. This has the fishy whiff of marketing about it. You could well be right. SLR sales have never lived up to Mercedes’ expectations, and special edition models with more power, honed dynamics and greater driver engagement are always a sharp hook with which to go out and snag some more buyers. If it works for Porsche…The left-hand-drive 722 series will be limited to 150 models worldwide, and will cost around £350,000 depending on the Sterling-Euro exchange rate. Mercedes opened up its order books to prospective buyers when the 722 was unveiled at the Paris Motor Show last September. All UK-bound 722s have already been snapped up.

So what’s new? Well, for an extra £32,500 over the standard SLR you get more power and less weight. Which is a good place to start. Recalibrating the hand-built 5.5-litre supercharged V8 engine’s electronic black box has pushed output to 650bhp at 6500rpm and 605lb ft at 4000rpm – that’s 24bhp and 30lb ft more than a standard SLR.The five-speed paddle-shift automatic transmission and its gearing remain unchanged, but you do get even more carbonfibre, with a new front splitter and rear diffuser, resulting in a 44kg drop in weight to a still super-size-me 1724kg

That’s it? Not quite. The steering has been tweaked, the suspension uprated, the ride height dropped, each corner fitted with lightweight alloy wheels to reduce unsprung weight, ceramic brakes are fitted, and the aerodynamics have been upgraded.Inside you get red stitching on the Alcantara-wrapped bucket seats and suede–covered steering wheel, red-ringed instruments and redesigned aluminium shift paddles. Oh, and a tacky 722 plaque on the centre console that would shame a Christmas cracker goody. In total, over 300 components have been enhanced or replaced. So it’s fast, but what about the brakes? Brilliant and awful in the same breath. The 722 is fitted with vast 390mm carbonfibre-reinforced ceramic brake discs complete with red calipers, supplied by Brembo. While the Sensotronic brake-by-wire setup has absolutely no problem in hauling the 722 back down from go-directly-to-jail speeds with the lightest brush of the floor-mounted pedal, they are frustratingly difficult to modulate; the pedal feels wooden and smooth deceleration is almost an impossibility. So it’s good in a straight line. What about corners? Here’s where the 722 falls apart. It’s the steering that’s to blame. Despite being razor-sharp and accurate, it never feels anything but dead. You’re given very little idea of what the front wheels are doing – not so cool in a car that can whip up to three times the national limit in a few minutes.Throw in a chassis that feels stiff but oddly inert and you’re left driving a very one-dimensional car. Which is a crying shame given the killer performance of its engine and brakes. Need to Know: Mercedes-Benz McLaren SLR 722 Edition How much? £350,000 Engine: 5439cc, 20v, supercharged V8, 650bhp @ 6500rpm, 590lb ft @ 4000rpm Transmission: Five-speed paddle-shift, rear wheel drive Performance: 0-60mph 3.6.seconds, 210mph, 14.5mpg How heavy/made of? 1724kg/carbonfibre, aluminium How big (length/ width/ height in mm)? 4656/1908/1251

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