The conversion adds a supercharger to the Lacetti’s 1.8-litre four-cylinder engine. This boosts the standard car’s 121bhp and 121lb ft to a more useful 170bhp and 170lb ft.
RML has improved the breathing with an Irmscher exhaust and there’s a new gear linkage and stiffer bushing for the gearbox. The rear brakes are unchanged, but up front there are 325mm grooved and ventilated discs with four-pot Alcon calipers, and the MacPherson strut front/dual link rear suspension is lowered by 30mm with 30 per cent stiffer springs and a dose of negative camber at both ends.
This prototype wears adjustable dampers, but for production it’ll have retuned conventional dampers.
The conversion is completed by leather trim, 17-inch Team Dynamics alloys shod with 215/45 Dunlop SP Sport Race tyres and a bodykit that does a decent impression of the racing car.
The plastic addenda isn’t just for show; the air dam feeds the intercooler and the aero kit balances front and rear lift and cuts the drag coefficient from 0.36 to 0.34.
A brief drive reveals a surprising amount of race-car DNA. Okay, so the cabin is largely unchanged – it still feels like a budget car and there’s insufficient shoulder support from otherwise comfy seats – but there’s a threateningly lumpy tickover and a promising sensation of rigidity.
It feels quick too, though it suffers from turbo-style lethargy below 2500rpm. Get past this gap and it pulls strongly until it hits the limiter with a BTCC-style fizz at 6500rpm. Rest to 62mph is achieved in a reasonable – and Citroën C4 VTS-beating – 8.0sec, but in-gear performance through the motor’s favoured 3000-5000rpm zone feels strongest.
The Lacetti’s pace is given a psychological boost by the noise. Gone is the groan of the normal 1.8, replaced by a concoction of naughtiness with a greedy induction suck, a distant supercharger spin and hissing twin tailpipes.
The gearbox is less satisfying; it’s notchy and feels fragile, with second to third gear changes taking real patience. Project leader Nève accepts there is still work to do, though internal changes are out of the question because of cost.
Altering the spring rates and adding some better dampers has transformed the Lacetti’s behaviour on a B-road.
There is still some slack in the steering around the straight ahead but it’s much keener to turn into a bend and, once there, weight feeds satisfyingly into the hydraulic system to give more feel than an electrically assisted rack.
Mid-corner body control is excellent. The Lacetti stays flat and rides ridges well, and those tyres provide massive grip, though the fronts looked decidedly second-hand after some hard driving. The front-wheel drive R+ understeers when pushed hard, and lacks the throttle-steering entertainment of a good hot hatch.
The roads of our test route were Milka-smooth so it’ll take a UK drive for a conclusive judgement on the Lacetti’s ride. The damping seems as well resolved as you’d expect of a car developed on British roads by a team such as RML. But it doesn’t like abrupt lateral ridges – an unexpected railway crossing sent an unpleasant shudder through the car.
There are still hurdles to be jumped before the R+ becomes a production reality. But commitment within Chevrolet is strong and we should expect at least a limited run from early next year. Local assembly in the pre-delivery inspection centres for each country it’s sold in should keep costs down.
The R+ is unlikely to worry the likes of the Skoda Octavia vRS, but as a budget family hauler with a touch of touring car it’s an exciting prospect. As long as Chevrolet remembers Louis’s philosophy, and makes it cheap.Alastair Clements