It’s easy to admire diesel technology – with all its efficiency, power, and torque. But it’s hard to love it. Diesel engines need to be strong and heavy in order to withstand the higher pressures. They don’t like to rev like gasoline engines, and while the best of them emit a reassuring purr instead of the usual clatter, they never really sound exciting like a high-performance gasoline powerplant. Last month, however, I fell in love with a diesel – and the unlikely cause of this was an electric supercharger. I was able to spend an afternoon with an Audi RS5 TDI – a prototype based on the RS5, but fitted with a 385 horsepower V6 diesel. That’s the same basic 3.0-litre V6 TDI offered in Audi’s many sedan and SUV models, but fitted with two turbochargers and an electric supercharger positioned behind the intercooler, and capable of spinning to 70,000rpm within 100 milliseconds. This translates to an ultra-quick response time – and because the instant boost of the E-charger does away with any turbo lag whatsoever, the turbochargers can be configured for high power instead of responsiveness. In fact, this diesel is quicker to react and more agile than virtually every turbocharged gasoline engine as well. There’s more to like too. With the help of external speakers, Audi has managed to create a pleasant growl. And the engine has been tweaked to easily race up to 5,500rpm, which is truly impressive for a diesel – it matches many gasoline engines too. Audi will bring the E-charger to market next year – and I hear from a lot of other carmakers that they are evaluating and working on similar systems. The main obstacle is the need for a 48-volt electrical system. That’s a considerable cost factor today, but these systems will become cheaper – as they are needed to enable a whole range of electrification technology and assistance systems. Electric superchargers will allow carmakers to simplify other components too. There will be less need for turbochargers with variable turbine geometries, and they will make life more difficult for the mechanical supercharger of course. Eventually, the technology could appear both on gasoline and on diesel engines – and it will be available in every vehicle class. As to Audi’s diesel portfolio, this V6 TDI with nearly 400 horsepower won’t be the end of the road. The brand will continue to refine the V8 TDI, and bring it up to 450 horsepower in future. Moreover, they are seriously considering a V10 TDI as well. These plans are in marked contrast to the strategies of BMW and Mercedes-Benz – both of whom abandoned V8 diesels several years ago. Will the lesson stick? So, the diesel is growing on me. But I stubbornly refuse to be converted to automatic transmissions – and I think it’s regrettable that an ever-increasing number of sporty cars are not offered with manual transmissions anymore. Of course, dual-clutch transmissions and modern torque-converter units have improved massively – they provide ultra-quick shifts, and acceleration times do actually improve. Carmakers claim that their sports cars are quicker when driven with an automatic than with a manual. And the paddles on the steering column add a racing feel. Moreover, they usually fare better in fuel consumption testing, although there is an element of cheating involved. In some regulatory cycles, manual transmissions are not allowed to upshift as early as their automatic counterparts. But there are reasons to remain loyal to the manual. First of all, automatics are more expensive – and where they are offered as an option, they usually cost dearly. They also add considerable weight – in some cases, up to 30 kilograms. While they may offer a wider spread of ratios, they will never be as efficient as a manual that works without hydraulics. And there is beauty in every simple and efficient engineering solution. But, most importantly, shifting yourself forges a bond between the driver and the car. I feel fully connected and in unison with a car when I row through the gears manually – and manage to execute perfectly matched shifting manoeuvres. Who cares about minimal gaps in lap times? In a sports car, I’m not out to win in Formula 1, but I want to enjoy a sensual experience. Even the most perfect automatic detracts from that. Curiously, a segment of the US market is especially keen on keeping manuals. A few years ago, both BMW and Audi had to learn that lesson and reintroduce manual transmissions on the BMW M5 and M6, as well as the Audi S4 and S5. Hopefully, that lesson will stick...
Write your Comment