The 2.0-litre HDi turbodiesel in the Peugeot 308 CC produces a peak 161bhp at 3750rpm, and 251lb ft of torque: a decent amount of thrust to pull along a car weighing 1736kg. On the open road, progress is stout without being outstanding; momentum takes a little effort to gain, but is more easy to maintain.
The HDi’s torque peak arrives slightly late by modern diesel standards, at 2000rpm, resulting in a slight pause in power delivery if the engine is revving below that point. You can partially mask this by selecting Sport, but the resultant low groan from a reluctant engine held in too low a gear soon gets wearing; while not outright noisy, this turbodiesel doesn’t make especially appealing sounds. Still, once past 2000rpm its pull is pleasingly consistent and relatively freely delivered to the 4500rpm limiter.
The six-speed torque converter auto ‘box teamed with Peugeot’s diesel engine performs tremor-free changes and is easily overridden with the manual mode, which, despite being designed for left-hand drive, is fairly convenient to use. The result is a civilised powertrain, if hardly a sporting one, but one that complements the CC’s cruising refinement well. Wind noise is contained to the point that, roof up, it’s easy to forget that this is a convertible at all, which is of course the point of coupé-cabriolets.