THE name BlueEfficiency denotes an eco-friendly model, according to Mercedes Benz. Some may consider the “Blue” tag a bit of a misnomer, green being the colour usually associated with ecofriendliness. But the company claims that cars bearing this moniker are designed with the “Blue” planet in mind. So what exactly does BlueEfficiency entail?
It is the umbrella term Mercedes-Benz uses to describe a raft of fuel saving measures applied to various models in its line-up. As these changes are model dependent and this test is about the C180K, we’ll keep our descriptions relevant to the best-selling C-Class. In this case, BlueEfficiency refinements refer to weight reduction, aerodynamic augmentation and a diminished engine size. More specifically, items such as a thinner – hence lighter – front windscreen, and thinner firewall insulation both contribute to weight loss.
Cleaner, smoother airflow is created courtesy of an undertray, a partially blanked-off radiator grille, sealing the joins around the headlamps, extra engine bay panelling, and a lower ride height. Other C-Class models already have a low drag coefficient of 0,27, but the C180K Blue boasts an even more slippery 0,25. Most notable of the changes is a reduction in engine size from 1 796 to 1 597 cm3.
Though this equates to a 12 per cent reduction in capacity, peak power remains unchanged at 115 kW and is produced at an identical engine speed to that of the 1,8-litre variant. Maximum torque, too, is still 230 N.m but developed a hardly noticeable 200 r/min further up the range at 3 000 r/min.
A longer, friction-optimised final drive ratio has been adopted for the differential, which creates an overdrive characteristic when cruising. Local versions of the BlueEfficiency do not sport the low weight, aero-tuned 16-inch alloys and low rolling-resistance tyres available in other markets. In total, these seemingly simple measures have helped save 0,7 litres off the amount used over every 100 km travelled when compared with a regular C180K.
Our calculated fuel index figure for this “Blue” model is 8,04 litres/100 km. Not too bad for an executive compact saloon. From the driver’s seat there is very little to differentiate this model from its siblings. It has all the usual bits and bobs, but the eagle-eyed will notice the gearchange indicator in the middle of the speedometer. This display shows the ideal point at which a driver should effect an up-shift. We found the system more than a little optimistic: if it is followed diligently, you will find yourself trundling along in top gear very soon after setting off, with the engine way below its torque peak. To make any sort of sane progress, one HAS to ignore the indicator.
Annoyance levels are amplified when you factor-in the clunky gearbox and horrid clutch pedal action of the manual Merc. On more than one occasion testers stalled when trying to set off… Automatic transmissions are less than ideal for an “eco” application. The energy-sapping torque converter is almost always less fuel efficient, so why hasn’t Mercedes developed a CVT or – better yet – an automated dual-clutch set-up, as is all the rage these days? Either option will be better suited to this application than this ungainly manual. As we said in previous road tests, the C-Class impresses with its on-road behaviour, and this model is on par with all its stablemates. Dynamically there is little to differentiate this model from others, especially considering that it still utilises the 17-inch rim/tyre combination. The only difference in the Blue model is the “on-demand” power steering. The hydraulic pump is only called into duty when turning.
When travelling in a straight line, a by-pass valve ensures that the pump is not driven and therefore does not unnecessarily draw power from the engine. Weighting of the steering action was found to be not ideal for all our team, some fi nding it too light, lacking in meatiness and feel. Performance is as one would expect, the session on our test strip resulting in a best zero-to-100 km/h run of 10,22 seconds and a 230 km/h top speed. And the car is typically Mercedes-solid, although on the noise, vibration, harshness (NVH) front some testers did note some engine noise intruding into the cabin. A result of that thinner firewall insulation, perhaps…?
TEST SUMMARY
The C180K BlueEfficiency is a worthy attempt by Mercedes- Benz to lower fuel consumption and CO2 emissions. Soon these measures – weight reduction, smoother aero packages, ondemand ancillaries, etc – will be introduced across the entire Mercedes range. This particular model replaces the 1,8-litre C180K. As it stands, this is a good start, and keeping pricing to a competitive level should make adoption of this technology more attractive to new buyers. However, will customers get over the idea of paying in excess of R300 000 for a 1,6-litre Mercedes? Only time will tell…
