Mercedes-Benz SL500 2012 review

The benefits of tighter emissions regulations are obvious enough: less time wasted at the coffee-and-muffin shops that pass for service stations and more time on the road.

Cheaper running costs and few compromises, if any, on performance. If you feel the need, you can even convince yourself you're saving the planet.

The downsides are less tangible. You don't become an immediate social outcast if you only pack four-cylinders, but you don't get the warm inner glow that a six or eight gives.

It helps if a turbocharger is fitted, because that suggests you're still a petrol-head at heart. But light-switch acceleration isn't the goal of turbos any more. Without an air pump, even modern engines must sacrifice economy or driveability; it's virtually impossible to deliver both.

Of course, carmakers employ marketing departments that are attuned to the social implications of all this. So while engines get smaller and shed cylinders, model designations stay the same. 

Mercedes’ AMG-tuned cars badged “63'' used to be naturally aspirated V8s of 6.2-litres capacity rather than 6.3. Depending on the model, outputs were different, and as carmakers go, that's a relatively innocent sleight of hand.

Now it's a full-on illusion. Some AMGs keep that engine, some move to a new 5.5-litre V8 with two turbos. But the badge stays. So you can't tell.

Engine

So I was left wondering what was under the bonnet of the SL500. When the fifth generation was launched 11 years ago, it stood for 5.0-litre V8, naturally fed. Now?

This V8 is never very loud, though, and of course the badge gives no clue to the fact that it's now 4.7-litres displacement, not 5.0, with twin turbochargers. All the fuel-saving tricks available have been fitted and the result is impressive average consumption of 9.1 litres per 100km. Helping achieve that figure is an extremely low drag coefficient of just 0.27 and electronic steering.

Value

The SLS sits above the SL in Mercedes-Benz sportscar hierarchy and the six-cylinder SL350 will start around half the price. Even the SL500 driven at launch will be about $130,000 cheaper than an SLS.

Design

It's easier to start with the letters. “SL'' stands for "super-light'' and this car traces its lineage back to the original 300SL Gullwing from 1954, which was based on a race-car. As the SL evolved, Mercedes forgot what the “L'' stood for and by the time it replaced its fabric roof with a folding hard-top in 2001, the SL500 weighed a whopping 1845kg.

No one would describe the new one as lithe, but it has switched to aluminium construction with a soupcon of magnesium and only used steel for the bits that really need it, such as the windscreen pillars. The result is a car 60kg lighter than the 2001 model despite being longer and wider.

The SL500  aims to be a luxury convertible with a turn of speed and a degree of style. On those goals, I'd score it two out of three. Its downfall is its design which, like most recent Mercedes, falls well short of its best work. Traditional roadster proportions are retained, with a long bonnet and cabin set well back.

There are modern echoes of the original, such as side air vents. But next to earlier SL models, thoughtfully lined up by Mercedes for comparison, the new one lacks grace. It looks best on the move but even then the nose can seem bulbous and headlights too large.

On the other counts, it's a significant step forward. It's not easy to make a folding roof convertible seem solid. Mercedes has achieved a more rigid body than before and it's noticeably tighter, with few creaks or groans. It's the first hard-top convertible I've driven that doesn't feel as though you've loaded the boot with flat-pack furniture.

The seats are good (with a fast power-forward button for access to storage behind) and the interior feels top-notch premium, with one blemish: black metal arms that support the roof are visible when it would be better if they were not. Round air vents and a miniature gearshifter come from the SLS and at last there's an electronic park brake.

This will be one of the first Mercedes with full iPhone integration and it also fits the industry's favourite new trick: a boot that opens or closes with a wave of your foot under the rear bumper.

The roof takes 20 seconds to open or close, which is about par for a folding hard-top but slower than most fabrics. This is relevant only because the car has to be virtually stationary for the roof to operate, a disadvantage fabric roofs can avoid.

Drive

Harsh Aussie roads will prove a tougher test than the tarmac of southern Spain, which has been smooth-paved with Euro-dollars. Even so, the SL's ride and refinement levels stood out. Roof down, a wind deflector keeps the cabin bluster free and conversations are possible at speed. Roof up, you could be in a conventional coupe it's so quiet.

One strange result of this is that you hear more of the engine with the roof up than with it down. Usually it's the other way around. The SL500 is effortlessly quick, reaching 100km/h in 4.6 seconds. It never feels remotely like a supercar, thanks to an absence of aural drama and (still substantial) mass.

But of course it's not meant to. The suspension copes well but gives priority to comfort over the ability to make rapid directional changes. With light steering and touring priorities, this is a swift cruiser that even in sport mode isn't primed for the starter's gun.