12-12-2006
Mercedes-Benz is extending its S-Class range with another diesel variant, the S 420 CDI. The new eight-cylinder model is powered by a state-of-the-art V8 CDI engine developing 235 kW/320 hp and 730 newton metres of peak torque.

This latest addition to the model line-up means that the luxury saloon range from Mercedes-Benz now encompasses two diesel engines, six petrol models and two body variants, along with the new 4MATIC all-wheel-drive system. The new S 420 CDI is available to order now, with deliveries to customers due to start in December 2006. The short-wheelbase model is priced at € 84,448 (net price € 72,800) and the long-wheelbase version at € 92,104 (net price € 79,400).

The new V8 model's strengths are effortlessly superior performance combined with moderate fuel consumption. The S 420 CDI powers from 0 - 100 km/h in 6.6 seconds and goes on to reach 250 km/h (electronically governed), all while returning fuel consumption figures below the magic ten litre threshold, burning just 9.4 to 9.6 litres of diesel per 100 kilometres on the NEDC cycle. With a fuel tank capacity of 90 litres, this equates to ranges approaching the 1000 kilometre mark.

Such impressive figures are down to the highly advanced eight-cylinder turbodiesel engine under the bonnet: from its 3996 cc displacement, the CDI unit with four-valve-per-cylinder technology delivers a maximum output of 235 kW/320 hp at 3600 rpm and a peak torque of 730 newton metres, which is on tap from 2000 rpm. Third-generation common-rail high-pressure injection technology with a maximum injection pressure of 1600 bar and an ignition pressure of 175 bar ensures efficient combustion. Optimised flow dynamics for the best possible gas cycle and twin turbochargers with variable-nozzle turbines promise high power and torque delivery. As many as five injections of diesel fuel per injection cycle, special orifice nozzles, piezoelectric injectors and highly effective exhaust gas recirculation all help to lower emissions significantly.

The new V8 powerplant is equipped as standard with a maintenance-free diesel particulate filter to cut untreated emissions even further, and also complies with the EU4 emissions standard. The engine development team was able to reduce noise levels by optimising the chain drive and fitting a rigid crankcase with large engine bearings as well as extra acoustic covers. The square bore-to-stroke ratio combines with a counter-rotating balancer shaft for outstandingly smooth operation.

Power transmission in the S 420 CDI is handled by the standard-fitted 7G-TRONIC automatic transmission with a DIRECT SELECT lever on the steering column, plus steering-wheel gearshift buttons. Not only does this combination guarantee that the tremendous reserves of power and torque are harnessed to optimum effect, the seven-speed automatic transmission's wide ratio spread is also perfect for motoring at low rev speeds – ideal for quiet, fuel-efficient travel. The top-of-the-range S-Class diesel model comes as standard with AIRMATIC air suspension including the Adaptive Damping System (ADS) and an all-round self-levelling function, while the latest-generation Active Body Control (ABC) can be specified as an option.

Text and photos courtesy of Daimler Chrysler AG