Mercedes-Benz SLR McLaren, Front Engine Rear Drive Supercar
Long, sleek, and low, with the cockpit well aft, the Mercedes-Benz SLR McLaren exudes pure glamour and extravagance, something that few mide-enigned supercars can match. It has the looks and proportions to make anyone turn and look and look.
The long, long hood, looks designed for a V-12, but that's because the engine, a hefty V-8, is set well back behind the front wheels, to improve traction and handling it's in the mold of a traditional sports car. Of course, mid-engine coupes get their weight distribution right naturally and better. Even so, the sheer extravagance of the SLR McLaren, coupled with its smoothness and glamorous interior make this car one of a kind well one of 3,500, which is how many will be built.
But this is no boulevard cruiser: it has an amazing specification: 626 bhp, front- engine, rear-drive, automatic transmission, top speed 207 mph, and masses of high-tech carbon fiber. No, this isn't some fantasy of a Corvette that might be, it's Mercedes-Benz entry into the supercar/fantasy car league. This has to compete with the Ferrari Enzo and Porsche Carrera GT- and it does. It is a shade faster to 60 mph than the Carrera GT, and has the same top speed. Sure, it takes about a second longer to get to 120 mph, but who cares?
What sort of numbers are we talking? 0-60 in 3.8 seconds, and 0-120 in 10 seconds! Forget the numbers; this hits you in the back just like a racer. I mean, your average 'fast' car takes about 8 seconds to get to 60 mph, and in that time you're well over the ton in the SLT McLaren. A bit of a mouthful of a name, but Mercedes wanted to capitalize on the fact that their engines power the McLaren Grand Prix cars.
Why not mid-engined?
But surely, you need a mid-engined layout to get the maximum performance don't you? Maybe, but the layout of the SLR McLaren is more practical. Easier to get into, and it actually has a large trunk! So, Mercedes-Benz calls this the Gran Turismo car for the 21st century. In that role, the only competitor is the Bentley Continental GT and you could have two of them for the price of one SLR!
Super sleek to look at, super smooth inside
From the side, this is one super-sleek looking car, with everything sloping up to the windscreen, and then there's that short, curvy roof. The car is actually a bit higher than it looks 49.6 in, which is quite a bit higher than competing mid-engine coupes.
The body style is not just for show, either. It was designed to give plenty of down force at high speed to maintain stability this is one area where McLaren were involved in the design. The composite doors don't swing outward, but upward from the windshield pillars and then inward out of the way. Then there are those sexy outlet grilles on the sides they let the hot air get away from the engine and those short, stubby exhausts.
From the front, the styling is less successful, the grille being rather garish. But this is certainly a very different car to look at. It gets the refinement of the SL with loads of high-tech features that push the cost to the stratosphere.
Complex carbon fiber structure and composite panels
Almost all of the svelte body panels and the structure itself make up a complex carbon fiber composite shell it's not just a tub with metal extensions, but the complete shell which includes the roof, rear wings and front and rear safety struts as well as the very rigid cockpit. There is an aluminum sub-frame to carry the engine, but the rest of the structure is carbon fiber.
Normally, the thousands of parts that make up the shell are laid up by hand, but Mercedes-Benz engineers have learned from the textile industry how to automate assembly of the carbon fiber. Even so, this is one mighty expensive body but light. Mercedes-Benz reckons it's half the weight of a steel body. The car weighs which seems a lot at 3,890 lb. It looks better when compared with the 4,300 lb of the SL 55AMG.
But… not so good for a car in the fantasy league. That's over 800 lb more than the Carrera GT, despite all that carbon fiber. Some of that extra weight stems from the layout. There's all that transmission to get the power from the front to the back that's absent in the Carrera GT or Enzo. Still, could do better.
Supercharged V-8 engine
To power the SLR McLaren, Mercedes dug into its array of standard engines, and got AMG to soup up the V-8 from the SL 55 AMG. This is also larger than the standard Mercedes mill, with a displacement of 5.4 liters. As on the current generation of Mercedes-Benz engines, there are two inlet and one exhaust valve per cylinder, instead of the fashionable four valves per cylinder. This hasn't held back the power output, not one bit.
The new unit has the same type of screw type supercharger as the SL 55 AMG, but the boost pressure is turned up from 12 psi to13 psi. So that the engine can sit below that ultra-low sloping hood, they've converted the engine to a dry sump, which is a good move.
It's not so much the 626 bhp at 6,500 rpm that gives the car is super performance as the amazing amount of low-speed power. Maximum torque comes in from 3,250 right up to 5,000 rpm. And it's a massive amount of pulling power with 575 lbft. What a superb engine this is, suitable for burbling along Hollywood Boulevard or foot flat on the floor to 200 mph and more….
A fully-automatic gearbox?
Yet despite that searing acceleration, this car has an automatic box. I don't mean a racing type semi-automatic with automatic clutch and gearshift, but a normal old slush pump automatic with five speeds some more modest cars have six-speed automatics. This car just doesn't need six speeds. With that massive low-speed pulling power you could probably out drag everything in sight to 150 mph with a four-speed box!
Of course, there are a pair of buttons on the steering wheel so you can change gear, but unless you're in hilly country, automatic works just fine.
How about getting the power on to the road? Well, there are the massive tires you'd expect on a car of this type, either 18 or 19 inch diameter, and the rear tires are about a foot wide. That's wide enough put a lot of power on the tarmac and they do. Of course, it's got all the electronics to help you keep control you get on lesser Mercedes.
Racing-type suspension and brakes
To show off the racing heritage, the car has double wishbone suspension front and rear, and the wishbones are forged aluminum. More like a racing car still are the brake discs: they're ceramic and reinforced by carbon fibers. The result is discs that will last a very long time, and carry on braking even when they get very, very hot. Brake fade at high temperatures would be a real problem on a car of this type just imagine how much energy you use slowing from 180 mph down to 40 mph a few times. Mercedes says that the brakes can provide 2,000 hp of braking power! Some brakes.
So that's the story under the hood. Inside the cockpit, though, there's a sense of luxury which is definitely what you need on a Grand Tourer. So far as I can gather, the SLR McLaren is more like a Grand Tourer than a racer when it comes to handling, and could probably do with some improvement in that area.
Adaptive spoiler and an air brake
Aerodynamics are very important on fast cars, and Mercedes-Benz worked with McLaren to get an almost smooth under body, to get the exhausts out at the sides this reduces drag and to put diffusers, which are used on Grand Prix cars, at the front and rear.
One of the features that Mercedes-Benz wanted was a spoiler that could be adjusted to suit the down force needed, and also act as an air brake. An air brake was fitted to the Le Mans Mercs in the 50s. This spoiler or wing, raises automatically, and adjusts its angle in steps as the speed increases. When the driver brakes heavily, the angle is adjusted to just 25 degrees from the vertical, giving some real air braking.
Still, you just can't get the weight distribution you get with a mid-engined coupe, so it's bound to lose out somewhere. On the other hand, though, this is one fantasy car that is practical enough to use on the road well on roads where there aren't serious speed limits and not much traffic. Also, it's good to see a really exciting alternative to the ultra-low mid-engine coupes that make up most of the entrants in the fantasy car league.