Peugeot’s diesel motors have always been among the best available, but even the fastest oil-burning 307 has had to make do with 110bhp. Not great when rivals claimed up to 150bhp.
Now the French firm has finally addressed that problem by putting the 407’s 136bhp turbodiesel under the bonnet. With a new 16-valve aluminium cylinder head and uprated injection system, it’s Euro4 emissions compliant and packs a massive 240lb ft of torque, up from 188lb ft.
If that wasn’t enough, an overboost function can momentarily increase torque by a further 15lb ft under full load. You can certainly feel the extra urge, which Peugeot says helps the HDi hit 60mph in 9.8sec, just under a second quicker than the 110bhp model could manage.
But while eager to pull even at high revs, the switch from low-rev torpor to boost-induced frenzy is a bit manic. Combined fuel consumption dips slightly, to 52.3mpg.
A new six-speed gearbox makes cog-swapping a pleasurable experience, offering a more feelsome action than the sloppy five-speeder of the less-powerful model.