BlueEfficiency Mercedes-Benz

For Refinement l Interior accommodation l Impressive economy and CO2 figures
Against Obstinate gearbox in Manual mode l Expensive to buy l Dynamic limitations
Background
Over the years, we’ve not been unaccustomed to sleek four-door saloons, but until Mercedes-Benz launched its first CLS in 2004 no car maker had quite had the gall to call its car a coupé.
Mercedes then claimed it had invented a new market sector. That’s something at least one manufacturer will do about once a quarter these days, with varying degrees of credibility, but Mercedes seemed to have managed it.
For a time, it had the market to itself. Some 170,000 CLSs were sold in the first-generation car’s life, and only recently has Audi replied with the A7 and BMW with the 5-series GT. There’s VW’s Passat CC too, closest in theme, if not in prestige and price, to the CLS.

Following the arrival of the latest-generation E-class, which the CLS uses as its underpinnings, here is Mercedes’ latest four-door coupé. Again it is pitched a little above an E-class in price and, again, its engine range is not dissimilar to the more staid saloon’s. Our test model is a 3.5-litre petrol CLS350 BlueEfficiency.
Question is whether the CLS still rules its marketplace, or whether its competitors have its measure.
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We are not the arbiters of design taste, but it’s fair to say that, although the appearance of the original CLS was very well received, we’re unconvinced that this new model has, thus far, quite garnered the same affection.
Although it’s more aggressive, it’s a less pure shape than before. But as with the original, Mercedes deserves credit for manipulating E-class underpinnings and considerable packaging demands into such a sleek overall profile.
There are, of course, a few changes to the platform to create the CLS, supposedly a more dynamic, athletic car than Mercedes’ very likeable but deliberately stoic executive saloon.
To that end, the CLS gets lighter body panels: aluminium doors and bootlid, front wings and parcel shelf. The front end is partly aluminium panelled, partly plastic, while much of the suspension is aluminium, too. Like the E-class, the CLS has a derivative of a MacPherson strut at the front, with a multi-link rear set-up. As standard, and fitted to our test car, the CLS comes with coil springs and two-stage passive dampers, although Airmatic air suspension is a cost option. Steering is, for the first time on a Merc this size, an electrically rather than hydraulically assisted set-up, with a quicker ratio than the E-class.
Power, to the rear wheels, comes from a V6 petrol engine driving through a seven-speed automatic gearbox. Outright performance models excepted, it’s unusual for us to test a large petrol variant of a car like this, but Mercedes is claiming that its BlueEfficiency program, including stop-start (see ‘Under the skin’), cuts fuel consumption by up to 25 per cent over its predecessors. Here, the 3.5-litre V6 develops some 302bhp and 273lb ft of torque.

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To call a car with 302bhp and 273lb ft quick is like pointing out that its wheels are round. Yet the real strength of the petrol V6 is not its outright performance but its clean, flexible power delivery and the ability to be silent and serene, or rasping and urgent according to demand. It suits the dual character of the CLS perfectly, and beyond that the ability to do 0-60mph in 6.5sec is merely a bonus.
In conjunction with the seven-speed automatic transmission, it makes for a cohesive and smooth drivetrain. The wheel-mounted paddles are fairly unnecessary since the ’box doesn’t respond quickly enough for really focused driving (see below). But leave it in Sport or Comfort mode and you rarely have to think about what the ’box is doing, whether you’re going for a more spirited experience in Sport or simply wafting around in Comfort.
So, is the extra poke that the petrol 350 offers worth the higher running costs it entails over the 350 CDI? Well, yes, if you’re looking for Merc’s coupé-saloon to be more sports car than everyday commuter. Being higher revving, lighter and generally more encouraging and urgent in its delivery, this is the better driver’s car thanks to its depth of response and flexibility as well as its more potent output.
Other benefits include surprisingly manageable economy. The stop-start (standard on 350 and 500 petrols and the 250 CDI) works seamlessly with this powertrain, stopping at just the right moment and firing up quickly. It does this with very little vibration, so it doesn’t interrupt progress at junctions if a momentary pause causes a cut-out. The brakes would benefit from more feel but stood up well on our track tests and offer excellent stopping ability.
Steer along an appropriate stretch of road in the CLS and it rewards with a subtle and well resolved poise and response. It never feels like a sports car, but it feels tauter and more alert to driver input than an E-class saloon. This is primarily down to firmer suspension and heavier steering, but the result is more than simply a less forgiving, low-roofed E-class.

The CLS’s standard suspension set-up includes two-phase passive dampers, whose tuning offers a firmer response to big chassis inputs (like big cornering forces) than to small ones (like town-speed ripples). Thus equipped, and on our test car’s relatively modest 18-inch wheels, the CLS displays a well resolved blend of ride comfort and body control. In less taxing driving, the CLS settles as the softer damper settings cast imperfections aside. There’s a little patter over uneven surfaces, but its ride is more cosseting than, say, an Audi A7’s, so it’s as relaxing as you’d expect a £50k car to be. At higher speeds, the accurate steering requires nothing but a nudge for lane changes, and its stability and refinement make it a seriously good cruiser.
Turn up the wick and you’ll find the CLS’s turn-in is precise, and once the long nose is tucked in the car will hold its line well unless provoked. In dry conditions it is inclined to wash into gentle understeer if pushed too hard, although with the right approach you can allow the rear axle a little slip to aid a tighter line. It’s prone to shifting uncomfortably on its dampers if you hit a mid-corner bump, though.
Other quibbles? The steering’s weight is sometimes inconsistent at town speeds, and the CLS is generally less satisfying to drive than a Jaguar XF, but it offers as broad a palette of dynamic ability as we’ve come to expect in this class.

Living

Interior compromises are few enough on the CLS that it will be a rare occasion when the coupé element restricts usability. Rear passenger space is generous, with sculpted seats that are comfortable and snug while also offering plenty of leg, head and elbow room, even for two six-footers. Getting in and out will require some dexterity from rear passengers, though, due to the low, sloping roof.
In the front, there is a sense of subdued quality that has become the norm in modern Mercedes. Many elements are recognisable from the E-class, including the main switchgear and control system, but the dash is unique to the CLS and makes for a suitably high-end appearance and atmosphere – enhanced in our car by various options including a £290 ambient lighting pack and £2295 memory seats (which also get full electric adjustment).
As ever, the Mercedes ‘Comand’ system requires some familiarity and lacks the intuitive nature of, say, a decent touchscreen. But thanks to the well laid out switchgear elsewhere, it’s still one of the most ergonomically sound cars to spend time in.
The boot is where the biggest compromise is made in terms of practicality, with a respectable capacity of 520 litres but a long, narrow space that is awkward to use. An optional £160 boot box, which folds away under the parcel shelf, can be pulled out and extended to variable depths. It’s the most useful and well thought out storage solution we’ve yet seen and worth the money, given that some could struggle to reach the boot’s farthest corners. Optional folding seats are a new addition to the CLS, but this £445 extra wasn’t fitted to our test car.
There is another element that makes the CLS350 one of the best executive cars on sale at the moment, and that is refinement. At idle we recorded a measurement of just 37dB. To put that in perspective, a Rolls-Royce Ghost produces 44dB, and the CLS betters the Rolls just slightly at 50mph and 70mph, too. This is one of the most refined cars we have tested, and in practice that goes a long way to making the Mercedes a truly calming place in which to cover miles.
Neither the CLS nor any of its direct rivals is an affordable car. Despite the lack of convenience compared with the E-class, the CLS is to all intents and purposes an executive-plus-priced car; think £50k rather than £40k for a mechanically equivalent E-class.
The CLS is so well equipped that we’d expect most customers to live without the £7000 worth of options fitted to our test car. And it’s competitively priced next to an Audi A7 and the BMW 5-series GT, which both command a premium.
Most running costs should be class representative, but this petrol CLS’s economy was excellent for a 3.5-litre V6 offering substantial performance. Overall, we averaged 29.1mpg, with a touring figure well into the 30s.
We’ve become accustomed to recommending a diesel as a matter of course in large vehicles. Given the refinement and pleasing nature of this engine’s power delivery, it’ll be no shame at all if that starts to change.

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Curiously, for a car aimed at being rather more dynamic than the conventional executive saloon on which it’s based, it is the CLS’s refinement that is its overall defining feature. Fitted with this smooth V6 petrol engine, the CLS is an exceptionally quiet cruiser. Perhaps that fits with the sleek exterior shape, if not the CLS’s intended dynamic ethos.
Think of it not as a sporting four-door coupé, then, but as a modestly booted and very hushed executive saloon with a modicum of dynamic ability. It’s at its most impressive when cruising, rather than entertaining. Those abilities combine with excellent fuel economy and an interior that’s a pleasure to spend time in. Enjoy all these qualities and don’t ask too much of the chassis and you’ll find the CLS is in its thoroughly impressive element.

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How much ?
* Price as tested £49,988
* Price as tested £49,988

How fast
* 0-30mph no data
* 0-60mph no data
* 0-100mph no data
* 0-150mph no data
* 0-200mph  no data
* 30-70mph  no data
* 0-400m  no data
* 0-1000m  no data
* 30-50mph in 3rd/4th  no data
* 40-60mph in 4th/5th  no data / no data
* 50-70mph in 5th  no data
* 60-0mph  no data
* Top speed  no data
* Noise at 70mph  no data
How thirsty?
* Test average  no data
* Test best/worst  no data / no data
Government figures
* Combined/urban  40.9 / 30.7 mpg
* CO2 emissions  161 g/km
How big?
* Length  4940 mm
* Width  1881 mm
* Height  1416 mm
* Wheelbase  no data
* Weight  1735 kg
* Fuel tank  67.0 litres
Engine
* Layout 6 cyls , 3498 cc
* Max power 302 bhp at 6500 rpm
* Max torque 273 ft at 3500 rpm
* Specific output no data
* Power to weight 174bhp per tonne bhp per tonne
* Installation F
* Bore/stoke 92.9x86.0 mm
* Compression ratio 12.0:1
* Valve gear 4 per cyl
* Ignition and fuel no data, Unleaded

Gearbox
* Type 7-speed Automatic
* 1st no data
* 2nd no data
* 3rd no data
* 4th no data
* 5th no data
* 6th no data
* Final drive no data
Suspension
* Front no data
* Rear no data
Steering
* Type no data
* Lock to lock no data
Brakes
* Front no data
* Rear no data
Wheel & tyres
* Size front no data
* Size rear no data
* Made of no data
* Tyres front no data
* Tyres rear no data