There’s a good deal to like about the new Smart Roadster. Funky styling, snug interior, mid-engine layout, compact dimensions and affordable price all contribute greatly to its appeal.If there’s a weak link it’s performance. The standard car’s 698cc three-cylinder engine is never going to rip up tarmac with just 80bhp. So what better way to up the Roadster’s virtues than by slotting in another three-cylinder engine to effectively double the power?
The starting point for this hot prototype is the upcoming Brabus version of the Roadster. Keen observers will already have noticed the body kit, upgraded 17in wheel and tyre combo and lowered ride height – all of which are already available as part of a long list of options for the new Smart.
Along with cooling vents in the rear side windows, they provide the Roadster V6 with a more aggressive stance and bullish appearance than the standard car. You’ll also find an FIA-approved fuel tank mounted in the nose section and a carbonfibre brace behind the racing seats.
The big news, however, is underneath the plexiglass rear window. It’s here that a unique transversely mounted V6 engine debuts. Created by mating two of Smart’s three-cylinder engines together on a common crankcase, it displaces 1396cc and weighs just 93kg all up.
But with two turbochargers running 1.2bar of boost pressure, it manages to near double the output of the standard Roadster with a gutsy 172bhp at 5550rpm. With 162lb ft it’s not short on torque, either.
For an engine that’s been thrown together in the space of just three months, Smart’s tiny V6 is surprisingly well mannered and much nicer to use than the three-pot unit. It pulls cleanly from idle with a smooth, progressive feel. But there’s a good deal of shove through the mid-range as the turbochargers come on song and it remains strong and refined high up the rev range.
A claimed 0-62mph time of "less than 6.0secs" and a top speed nudging 140mph sound impressive, but even they don’t do justice to the true performance.
It sounds the business too, going from a hushed thrum to a growl as you hit the 6300rpm red line. The best part, however, is a high- pitched whistle as the turbocharger wastegates dump pressure on the overrun. Think Group B rally car from the late ’80s and you’re not far wide of the mark.
Drive is channelled to the rear wheels via a beefed up version of Smart’s sequential six-speed Getrag gearbox, reworked for five speeds.
Equipped with updated electronics, it shifts more positively with the V6. Backing up the wholesale boost in power is a heavily reworked suspension. The changes are similar to those reserved for the Brabus version, with stiffer bushings, springs and dampers at each end, along with a 20mm reduction in ride height.
The low-speed ride is firm but bearable and the steering provides the same purity as the standard Roadster. Throw in an almost complete lack of roll during cornering and you’ve got the basis of one great-handling car.
The abundance of power delivered to the rear wheels and the absence of traction control allows easy oversteer, however any tail-out action remains progressive and easily controlled.