First drive: Mercedes’ V8 monster slakes its thirst

A SURPRISINGLY economical 400kW monster twin-turbo V8 has made its debut in Australia under the long bonnet of the Mercedes-Benz CL63 AMG.

The engine is one is one of two new V8s in a facelift of Mercedes’ range-topping coupe that also includes fresh styling and a raft of new hi-tech features such as active lane keeping.

Facing the need for better fuel efficiency instead of horsepower at all costs, Mercedes and its AMG tuning division downsized the V8s that are making their debut in the CL before being spread across the Benz large-car range, including the S-class from early next year.

Both engines run two turbo-chargers, have direct injection and fuel-saving measures that come under the Mercedes BlueEfficiency ‘green’ banner.

For those who don’t particularly care for the environment, Mercedes is still happy to sell you a CL with one of two V12 engines, both of which consume a rather environmentally unfriendly average of 14.3 litres per 100km.

The two new V8 engines replace the standard 5.5-litre V8 and the big 6.2-litre V8 that was the first unit to be developed by AMG rather than Mercedes.

The regular V8 engine is now 4.7-litres, while the AMG special is 5.5-litres.

Interestingly, the more potent AMG engine is actually the most efficient of the two, partly because it runs an idle-stop system that kills the engine when you pull up and starts it up again when you are ready to go.

Remarkably, it consumes an average of just 10L/100km which is 25 per cent less than the thirsty 6.2 litre V8 it replaces.

Left: Mercedes-Benz CL63 AMG. Below: Mercedes-Benz CL500.

The new 5.5-litre AMG special, which is confusingly fitted to the CL63 model, uses direct injection (with 180 bar piezo injectors) to help generate 400kW at 5500rpm and a whopping 800Nm from 2000-4500rpm. That means four per cent more power than the 6.2-litre V8 and 27 per cent more torque.

This allows the big CL to dash from zero to 100km/h in 4.5 seconds, the same time as the previous model.

To aid efficiency, the new V8 tops up the battery using kinetic energy from braking, and has an electric on-demand oil pump.

It runs a seven-speed automatic transmission, as previously used in the SL63, with a wet clutch instead of a traditional torque converter.

The new CL500 is the first Mercedes to run the new 4.7-litre twin turbo V8 that replaces a 5.5-litre naturally aspirated unit.

With direct injection, four valves per cylinder and a turbocharger for each cylinder bank, this engine winds up to produce a maximum power output of 320kW at 5250rpm and peak torque of 530Nm from 1800-3500rpm.

This represents a 12 per cent improvement in power and a 32 per cent boost in torque. The main benefit the new engine brings is the area of efficiency as it uses 20 per cent less fuel than current naturally aspirated unit for an official fuel consumption average of 11.1 litres per 100km.

The CL500 runs a conventional torque converter seven-speed automatic transmission.

There is enough punch to sling the big rear-drive coupe from standstill to 100km/h in 4.9 seconds.

The company calls this CL the CL500 BlueEfficiency, which refers to the Mercedes environmentally friendly-themed sub-brand.

As part of the BlueEfficiency package, the CL500 gets on-demand alternator that kinetic energy charging system, an electric fuel pump and hydraulic steering assistance with an electric pump. Surprisingly, it doesn’t run fuel saving idle-stop technology, despite being tagged with the BlueEfficiency name.

Mercedes says both of its new V8 meet the Euro 5 emission standard, even though Australia is at least four years away from making this standard mandatory.

Given it is the range topping luxury coupe (not counting the hard-edged SLS), the CL must look up to date, so Mercedes has given it an exterior upgrade.

Some of the changes might be a bit hard to pick, but Mercedes has changed everything forward of the A-pillar as well as some of the car’s tail as well.

At the front the CL gets new guards, bonnet, grille and oversized three-pointed star as well as curving headlights with new LED daytime running lights. New-look LED tail-lights, a new bumper with integrated exhaust pipes grace the rear.

Mercedes has also added several hi-tech features to the CL to maintain its position at the top of its tree, including a feature that aims to stop drowsy drivers drifting out of their lane.

This is a continuation of the existing system that senses when the car is easing out of the lane without its indicators on and sends a vibration through the steering wheel to alert the driver. Now the system will brake the wheels on the opposite side of the vehicle to bring it back into line.

The new CL also uses an advanced blind spot detection system which not only alerts the driver of a car in its blind spot, it senses if the driver is moving into a blind spot where a vehicle is lurking and brakes the wheels on the other side of the vehicle to avoid a collision.

Other upgrades include a more advanced night vision system that now also identifies pedestrians in colour, yellow in most conditions and red if they are deemed a danger.

The CL also picks up the Splitview feature that allows for passenger to see different information on the dash mounted screen, so the passenger can watch TV which can’t been seen by the driver.

There is also an upgraded entertainment system with room for 2500 songs on a hard drive.

The CL continues to run the constantly variable suspension system, called active body control, which is hydraulic (not airbag). This system has been upgraded to react to crosswind and adjust the dampers accordingly to keep the car in a straight line.

It now also has a constantly variable steering gear ratio allowing for less steering input at lower speeds.

Mercedes says customers of these kinds of vehicles enjoy customising them and as such has introduced several different interior combinations including four different types of woodgrain.

Leather comes in two types with five different colour combinations.

Customers can also change the colour of the ambient lighting which a choice of yellow, white or blue.

The V8 CL500 kicks off the CL range at $337,000, while the V12 CL600 is $425,600. The V8 CL63 AMG costs $423,300 while the V12 CL65 AMG caps of the line-up at $519,250.

2011 Mercedes-BenzCL-classpricing:
CL 500 (a)	$337,000
CL 63 AMG (a)	$423,300
CL 600 (a)	$425,600
CL 65 AMG (a)	$519,250