Speed restrictions during our drive on a damp test track at Volvo’s Gothenburg headquarters mean it was only possible to get the broadest of hints about the car’s other dynamic qualities.
There’s plenty of grip, and the S60 feels nicely balanced. The compact size of the engine contributes to a lower centre of gravity and also means the weight distribution between the front and rear axles is improved compared to the previous generations of sporty Volvos with five or six-cylinder lumps under the bonnet.
The steering is a touch too light and doesn't react with any enthusiasm to mid-corner inputs. The automatic transmission feels a half-step behind the engine when it is left to its own devices, and the paddles behind the steering wheel don’t permit pleasingly razor-sharp shifts either.
From outside the car, the prototype powerplant sounds deep-throated enough to betray the fact there’s only four cylinders at work under the bonnet, a sensation that’s augmented by a trick Polestar exhaust system.
There are some similarities with the blunt-edged, rasping note of the Mercedes-Benz A45 AMG (which has a single-turbocharged four-pot engine) and even a rally-car-style exhaust crackle on deceleration too.
Inside, though, the noise dominates the cabin in a way that’s perhaps a little too unrelentingly boorish; fun in small, exuberant bursts, potentially overwhelming if it was a permanent soundtrack to every journey.
There’s plenty of time for Volvo to work on fine-tuning the elements of the packge, because at present there’s no word on when or if this engine would ever come to market, or if there’s a valid business case for a car fitted with it.
Such technology is unlikely to come cheap, and the question is whether a sports saloon with a four-cylinder engine, albeit a very clever one, would ever possess the same evocative allure as a similarly priced rival with six cylinders or more.
Such a debate is for the future. For now, the Swedish party line is that the engine is purely a concept to highlight the performance potential of its Drive-E units. If it can marry this unit's potency with some of the attractive economy and emissions benefits that the rest of the new engine range is providing, Volvo might have the basis for the perfect thinking man’s performance car.
For now, the S60 concept does a compelling job of underlining that downsizing of engine capacity doesn’t necessarily have to come with an attendant reduction in fun.
Get the latest car news, reviews and galleries from Autocar direct to your inbox every week. Enter your email address below: