“Sports-car torque and responsiveness, with B-segment economy, quietness and emissions ”
Gabor Szeczenyi, motoring journalist
The 2- to 2.5-litre class became an exciting battle between two new engines for 2009: the latest Mercedes four-cylinder diesel, as found in the all-new E-Class, and the return of a legend in the form of a five-cylinder Audi turbo in the TT-RS.
It was the Stuttgart oil-burner that won out, however, ultimately taking victory by a comfortable margin of 45 points. As jury member Tomas Hyan from Automobile Revue in the Czech Republic says, “Great progress has been made by Mercedes with this engine. There’s more power, more torque, less consumption and fewer emissions.”
Such impressive performance is the result of an extensive R&D programme. The new diesel, which is sold under the BlueEfficiency badge in three outputs (134, 168 and 201bhp) boasts a host of technical innovations. First among them is fourth-generation common-rail direct injection, delivered via piezoinjectors and featuring a 400bar increase in the maximum rail pressure, which now stands at 2,000bar for the C 250, E 220 and E 250 CDI BlueEfficiency models.
These variants also mark the debut of two-stage turbocharging in Mercedes-Benz diesel cars. The smaller, high-pressure turbine is located directly at the exhaust manifold and rotates at up to 215,000rpm. Benefits of the system include improved start-up performance and peak output, and a larger intercooler is also fitted.
In the E 200 there is a single-stage turbo with variable-nozzle turbines. Here, the lower engine power enables a smaller turbocharger to be used. The result is fuel consumption of 5.3 litres per 100km (53.3mpg) on the NEDC combined cycle and 139g/km of C02 emissions. In the face of this all-round efficiency, judge John Carey, from Wheels magazine in Australia, was moved to comment that, “The new Merc diesel proves that engine downsizing in large cars doesn’t have to hurt.”
Results
1. Mercedes-Benz Diesel 2.1-litre (BlueEfficiency E-Class, BlueEfficiency C-Class) 225
2. Audi 2.5-litre five-cylinder Turbo (Audi TT RS) 180
3. Subaru 2.5-litre flat-four Turbo (Forester, Impreza, Legacy) 144
4. Peugeot-Citro?n-Ford Diesel 2.2-litre (Citro?n C5, C6, C8, Peugeot 407, 607, 807, Citro?n C-Crosser, Land Rover Freelander, Mitsubishi Outlander, Peugeot 4007, Ford Mondeo, S-Max, Galaxy, Jaguar X-Type) 131
5. BMW 2.5-litre DI six-cylinder (Z4) 121
6. Honda 2.4-litre four-cylinder (Element, CR-V, Edix, Elysion, Odyssey, Accord/Acura TSX, Accord USA) 84
