Mercedes SLK 55 AMG revealed

By Jack Rix

23rd August 2011

These are the first official pictures of the all-new Mercedes SLK 55 AMG and instead of matching the five and six-cylinder units used in the Audi TT-RS and BMW Z4 35is respectively, Merc is sticking with a V8 engine for its flagship SLK.

Based on the twin-turbo unit found in the S 63, CL 63, CLS 63 and E 63, the new naturally aspirated 5.5-litre powerplant is the most efficient V8 engine in the world. Fuel economy and CO2 emissions of 33.6mpg and 195g/km are impressive, as is the fact that it still outguns rivals with 416bhp and 540Nm of torque.

Fitted with a 7G-TRONIC semi-auto gearbox as standard, 0-62mph takes 4.6 seconds - three tenths down on the four-wheel drive TT-RS, but once into its stride it should have the measure of its rival.

The fuel economy improvements of around 30 per cent versus its less-powerful predecessor are thanks to a stop-start system fitted as standard, direct injection and an ingenious sytem that deactivates half the cylinders on light loads.

With the transmission set to C (controlled efficiency), between 800 and 3,600rpm and when full acceleration isn't required, four cylinders shut down completely. Flex you right foot though and they fire up again within 30 milliseconds - a similar system is used in F1 cars to preserve fuel during pit stops and safety car periods.

To make the most of the multi-layered V8 soundtrack a sports exhaust with active flaps is fitted as standard. Below 2,000rpm the flaps remain closed, silencing the roar, but as the revs rise the flap  open partially at three set angles, before opening fully as you close in on the 7,200rpm red line.

Torque vectoring helps to maximise traction, by grabbing the wheel with the least grip, while standard AMG sports suspension is stiffer and cuts body roll. For an even more extreme experience an AMG handling pack can be ordered firming the suspension up even further, as well as adding a rear differential and lighter composite brakes at the front.

Lightweight wheels, a chunkier bodykit and 'V8 AMG' lettering under the SLS-inspired side gills are the most obvious exterior changes, although on closer inspection the horizontal bar on the grille and front spoiler are finished in gloss black while four chrome-tipped exhausts protrude at the rear.

On the inside, additions include an AMG-specific steering wheel, flattened at the top and bottom, covered in perforated leather and with aluminium shifters mounted behind it. Sportier dials are added two while AMG branded sports seats offer more support and can be finished in two-tone leather. Also available as an option is a panoramic roof with 'MAGIC SKY CONTROL'. At the touch of a button the glass roof can be made transparent or opaque.

There are no prices yet for the third generation SLK 55 AMG, but UK deliveries begin in January 2012.