By: Jason Woosey
Now it's no secret that diesel engine development has really come a long way in the last few decades and it's been a long time since seeing a diesel engine in a top-end luxury saloon evoked any kind of surprise reaction.
But a diesel engine in a hard-core performance car? That's still a very rare commodity, but it's an idea that Audi is exploring wholeheartedly with its new RS5 TDi concept car.
Though it's strictly still a “technology study” and there's no word on if or when something like this would ever hit showroom floors, it is an impressive and realistic indication of where Audi could be going with its engine technology.
At the heart of the RS5 TDI concept is a 3-litre twin-turbo V6 diesel motor that delivers 283kW and 750Nm and redlines at 5500rpm. It effectively matches the power output of Audi's 4.2 V8 TDI.
According to its maker, the RS5 TDI will sprint from standstill to 100km/h in just four seconds flat and reach a top end of 280km/h.
Its better-than-expected acceleration is partly down to the fact that an electric motor replaces the exhaust-driven turbine in one of its turbochargers, allowing the compressor wheel to spin beyond 70 000rpm within split seconds, long before the exhaust system has built up any real pressure.
The electric turbocharger is powered by a recuperation-fed 48-volt electrical system, which Audi is developing for use in future showroom-bound cars.
The other turbocharger is linked to the exhaust and provides an additional 2.4 bar of boost once things are nicely on the boil.
Then, of course, there's that diesel efficiency advantage, which Audi says amounts to a figure of 5.3 litres per 100km on the combined cycle. Sure, it's laughable to think you'll get anywhere near that outside of the laboratory and in that big bad place called the real world, but it will at least have a tangible economy advantage over an M4 or C 63.
Would diesel be the poison for your dream performance car or are you still a committed rev-head?