SL65 ( aim, fire and hold on tight )

Road Test: Mercedes-Benz SL65 AMG - A beast to take your breath away If you want to stop accelerating when you reach 155mph, then this is the car that will bring you safely back down to earth. John Simister reports

23 November 2004

SPECIFICATIONS

Model: Mercedes-Benz SL65 AMG Price: £145,970 Engine: 5,980cc, V12 cylinders, 36 valves, twin turbochargers, 612bhp

4,800-5,100rpm, 738lb ft 2,000-4,000rpm Transmission: five-speed automatic gearbox, rear-wheel drive Performance: 55mph, 0-60 in 4.1sec, 18.7mpg official average CO2: 362g/km

I flew in a Hawker Hunter fighter once. Yes, already you can guess what is coming. But let me explain just how your first encounter with the accelerator pedal of the Mercedes-Benz SL65 AMG brings on a sensation akin to jet-propelled take-off.

You are taxi-ing gently along at a gentle 50mph or so. Squeeze the accelerator - do not floor it, that can come later - feel a momentary pause and then a whooshing roar like that of a jet engine muted through a flying helmet and earphones. With this roar the nose rises and you are pinned in your seat, limbs growing heavier. The view ahead compresses, the thrust is relentless and you have to do nothing but keep your right foot in position.

Then you have to ease off, otherwise you will either become airborne (so you think) or you will smite something slower very hard or you will be deprived of your pilot's licence and your freedom. But what a sensation you have just had. It is one thing to drive a massively fast car and work quite hard to realise its speed - you know, changing gear and that sort of thing. But with this one you just aim, fire and hold on tight.

Maybe, if the road is not quite runway-smooth or has a few damp patches to match those on your brow, the escape-velocity thrust is not quite so missile-straight. It is an odd sensation to get wheelspin and a squirming of the tail when you might be pressing the accelerator just halfway or less, but it happens here. The electronic stability programme (ESP) system reins it in - press pedal, hear whooshing roar, feel squashed, sense ESP intervention, is a sequence which happens routinely

- but the forces at work are extraordinary.

With the ESP switched off, the SL65's tail will flick sideways in almost exact concert with your right ankle's downward flick if the engine is already pulling and you are already turning, and it is a little worrying even if it does stop the flick the instant you ease the power. In fact the ESP never entirely goes to sleep; it is merely attenuated when nominally switched off, there in the background to protect us from ultimate folly.

What is the source of this insane energy that makes this SL65 the fastest roadster that AMG, Mercedes-Benz's official engine tuner, has yet created? (The most expensive, too, at £145,970.) The SL600 on which this AMG is based already has a 5.5-litre, twin-turbo V12 engine which is surely plenty powerful enough for most tastes (500bhp, 589lb ft of torque). And then there is the AMG version of the V8-engined SL, called SL55 AMG and also featuring 500bhp. Clearly, though, the temptation to apply the AMG treatment to that V12 was too hard to resist, especially as there are power supremacy scores to settle in the rarefied world of epically rapid and possibly pointless supercars.

So the SL65 gets extra engine capacity (now 6.0 litres, and do not ask about the numerological mismatches), and thanks also to bigger turbochargers blowing through an enlarged intercooler, camshafts designed to let more petrol/air mix in and exhaust gases out, and a free-flowing and notably sonorous exhaust system, the engine now creates up to 612bhp. That is nearly 100bhp more than a Ferrari 575 Maranello, poor thing. More significant still is a torque output of 738lb ft, which, if converted to a metric measurement, shows a point being strongly made: the figure is a neat 1000Nm (it stands for Newton metre).

Here is a car, a hefty and heavy car, which will reach 60mph from a standstill in around four seconds. Flat out it stops accelerating at

155mph because its engine management, instructed by an informal let's-limit-speed agreement between some car makers (Porsche, Ferrari and Lamborghini are among those not interested), says it must. If uncorked it might do 200mph as the rev counter touches the 6,000rpm red sector. Which means that in the top, fifth gear of its automatic transmission the SL65's engine is ambling at just 3,000rpm as the speedometer touches 100mph. It also means that the SL65 is, in theory, nearly as rapid as the SLR McLaren. As it is, that 155mph arrives in just over half a mile from standstill.

Why make a car which is so fast? Pride plays a part, but in making a car able to cruise effortlessly at more normal speeds - say under 100mph with the driver exercising due prudence - a car maker inevitably ends up with a car able to go very fast indeed when it does exert effort. Bear in mind, too, that cars such as this AMG also have to be able to stop from the speeds of which its capable, so they have extremely powerful brakes. The SL65's braking distances are, I surmise, around a third of those quoted on the Highway Code, figures long overdue for updating as they have not been revised for a good half-century.

So, is this SL65 AMG the epitome of fast-car heaven? It has many good points beside its crazy pace. It is beautifully made, its automatically-folding metal roof is a fine piece of engineering, and it looks surprisingly discreet for such a hot rod. The sound of the engine is delicious. The semi-active suspension gives a beautifully controlled and level ride despite the underlying firmness that comes from such wide, low-profile tyres. And the automatic transmission works with the mix of speed and smoothness that an ample engine makes easy. There is a manual mode, activated by steering-wheel buttons, but with torque like this it is hardly necessary.

For all that, though, it is not a machine of perfect dynamism. The steering can feel uncertain and slightly disconnected at speed, requiring more of an input than you might expect given its swift response at a slower pace. That may be a built-in "sneeze factor" to prevent twitches at 155mph, but it goes too far. And those brakes, fully electronic with no direct mechanical connection between pedal and wheel, feel springy with a long pedal travel and little feeling of something solid to stand upon. You have to take them on trust.

But the engine remains something to marvel at, for I have never experienced another road car engine with such an inexhaustible and accessible supply of thrust. Paradoxically, it caused me to drive quite sedately much of the time, relaxed and confident in the need never to have to jockey for position in the traffic jungle. I knew that if I needed or wanted to overtake, or get away first from traffic lights, my wish would be granted at a mere ankle flex. Driven normally, nothing, but nothing, outruns AMG's 612bhp V12 away from rest.

There is an S-class saloon with this engine, too. Imagine that with an S320 CDI badge on the tail.

THE RIVALS

PORSCHE 911 TURBO CABRIOLET £96,130 A rival for the open-top side of the SL's dual personality, the Porsche seems almost cheap in this company. It is based on the revious-model

911, extracts 420bhp from its 3.6-litre flat-six engine, has 4WD and is a sensational drive.

FERRARI 575 MARANELLO £156,700 Another V12, this one of 5.7 litres and 515bhp. Yet it still manages virtually SL-matching performance, partly because its six-speed manual transmission (or the paddle-shift version of same) is more efficient. A demanding but fabulous car.

ASTON MARTIN VANQUISH £174,000 This extensive revamp of the Vanquish, the first Aston Martin of the new generation series, raises the 520bhp from its non-turbo 6.0-litre V12. It is less bombastic than the SL but still hugely fast and a more satisfying driver's car.