Mercedes-Benz CLS450

Classy ‘coupe’ ushers in six-cylinder renaissance

TONY O’KANE

IN 2005 Benz dropped a bombshell with its first-gen CLS. ‘Four-door coupes’ are thick on the ground these days, but back then the term was truly alien. The second-generation model that succeeded it in 2011 was similarly jaw-dropping thanks to more muscular surfacing and swollen guards.

Now there’s a third iteration of the CLS formula, but the ocular impact this time around isn’t quite so mind-blowing. Not because it’s ugly, mind you. The opposite in fact. It still looks great, just a little less extrovert.

The real leaps are found under the skin. There’s a completely new six under the bonnet, with the cylinders arranged in line rather than in a V format and sporting a turbo hanging off one side. Underpinned by a 48-volt electrical architecture, internal combustion power is augmented by an electric motor sandwiched between the engine and nine-speed auto, which can deliver up to 250Nm of extra torque when the accelerator is firewalled. Given the 3.0-litre turbo already develops a healthy 270kW and 500Nm on its own, total system torque is 750Nm, which is enough to zip the 1940kg CLS450 to 100km/h in a very respectable 4.8 seconds. But it’s not speed that impresses the most in the CLS450. It’s the silky seamlessness of this powertrain, and the effortless thrust it’s capable of delivering.

Sport and Sport+ might liven up the powertrain, increase the exhaust’s volume and stiffen the 450’s standard air suspension, but despite the ‘coupe’ tag this is no sports car. In Eco mode, the CLS450 transforms into one of the smoothest, quietest grandtouring devices around. It wraps near S-Class refinement in a sleeker bodyshell, and while rear headroom is predictably limited, the relaxed posture promoted by the canted backrest, and the rear compartment’s generous leg and elbow room still promise long-distance comfort. What’s more, that turbo six is virtually silent at a cruise, ticking over a smidge above idle in ninth gear 110km/h and transmitting barely any vibration into the cabin.

Not only does the nine-speed bring refinement, it’s also a boon for efficiency. With an official figure of 8.7L/100km, the CLS450 is more economical than you may expect a two-tonne, all-wheel drive turbo six-cylinder to be.

Sound too snoozy for your tastes? The CLS53 amps things up with a higher-output version of the M256 that features an electric compressor, 320kW, 520Nm (770 with EQ boost) and trims zero to 100km/h to 4.5 seconds, but those simply searching for a car that typifies those Benz qualities of elegance and effortlessness need look no further than the CLS450.

TONY O’KANE

Silence is golden

The powertrain’s greatest trick is its ‘sailing’ function, which shuts down the engine when coasting and decouples the transmission from the wheels to reduce drag, save fuel and cut CO2 emissions. The 450 will coast in this way for a great distance and passengers will scarcely be able to work out what’s going on. The engine shuts down and restarts so smoothly and instantaneously, the only way you can tell it’s running is by watching the tacho like a hawk.