THE BEST NEW AUTOMOTIVE ENGINE OF 2009

This year the Best New Engine winner is Porsche’s 3.8-litre 385bhp flat six, as fitted to the 911 Carrera S, giving the coupe version a top speed of slightly over 300km/h (188mph). But it wasn’t just the power – of which there is plenty – that impressed the judges. Marc Noordeloos of Automobile magazine said, “Leave it to Porsche to build a near-400bhp engine that returns such impressive fuel economy. Enthusiasts should take comfort in the fact that the naturally aspirated engine may not be dying after all.” As well as a 200cc size increase, the new engine is up by 30bhp over the previous incarnation, with a 15% decrease in CO2 output. Porsche maintains that one of the secrets of its success is the Direct Fuel Injection (DFI), which has been migrated over from the Cayenne V-engines. This system gives a faster throttle response with more precise metering, meaning less fuel is wasted when the accelerator is released as engine revs drop more sharply, thus improving economy and emissions. No residual fuel is left in the intake chamber. In terms of general architecture, this engine has four overhead camshafts, four valves per cylinder, variable valve timing (VarioCam Plus), hydraulic valve play compensation, and integrated dry sump lubrication with an on demand oil pump, which further reduces parasitic losses. There is a double-chamber exhaust system with pre-catalyst and main catalyst close to the engine so that it warms up quickly, and an oxygen sensor control with two pre- and two downstream-catalyst sensors. The compression ratio is up from 11.3:1 on the 3.6-litre to 12.5:1. Getting power to the road is a new Porsche Doppelkupplungsgetriebe (PDK) or double-clutch gearbox with seven forward speeds. The company says it offers ‘the driving comfort of a torque converter-equipped automatic transmission with the dynamic manual gearshift functionality of a sequential racing gearbox’.