THE 2.0-litre turbo-diesel engine used in the 406 HDi produces 82kW at just 4000rpm and 255Nm of torque at a super-low 1750rpm. It uses state-of-the-art turbo diesel features such as common rail injectors, direct injection, twin balance shafts, air-to-air intercooler and an alloy cylinder head with a single overhead camshaft. The combination of high fuel feed pressure, very small fuel-injector holes and computer management of each system component adds up to extremely accurate and efficient engine operation. The turbocharger uses variable exhaust nozzles to control the flow of turbine-driving exhaust gases depending on engine speed and load. A variable swirl intake system, controlled by a butterfly valve, optimises combustion efficiency and assists with lowering both fuel consumption and exhaust emissions. The long stroke dimensions also help in the creation of torque. The engine will also start readily without pre-heating in temperatures above zero degrees celsius. The Peugeot 406 turbo-diesel engine is the same as that used in the Citroen C5 turbo-diesel.