Wednesday, July 17, 2013

Audi R8 e-tron electric supercar more than torque

A delight to drive, but Audi’s R8 e-tron won’t make it to showrooms because of the cost of production.
The Audi R8 e-tron is a genuine electric supercar, and also a prime demonstration of the limitations of battery power.
Consider the performance: zero to 100km/h in 4.2 seconds, and an electric car lap record of the tortuous Nurburgring in 8:09 minutes.
Then consider the range: nominally 215 kilometres, but at that speed not much more than two laps of the 20.8 kilometre Nurburgring.
And if that doesn’t turn you off, ­­the e-tron version of the R8 costs considerably more to build than anything in the petrol range, which is already topping the $400,000 mark.
Why so expensive? The unique technology to keep the batteries at optimum temperature, to cite just one example, takes up most of the nose and looks like scientific equipment from a Mars mission.
Audi recently announced that although the R8 e-tron (in Audi-speak, e-tron means anything powered by something other than a conventional petrol or diesel engine) is production-ready, it won’t make it to showrooms. It simply isn’t possible to cover costs.
Still, a chance to drive the car (just like Robert Downey jnr in Iron Man 3) and talk to the engineers was not to be missed.
Audi insists much of the technology will make it into other production cars, though the company seems to be heading more towards “range extender” cars, which we’ll come to shortly.
The location for the R8 e-tron drive was Berlin’s mothballed Tempelhof Airport, which was the busiest in the world in 1925, receiving – wait for it – 11,000 passengers. Later it was the centrepiece of the Berlin airlift and one of the US planes involved is still on display.
On a couple of spare hectares of asphalt, a temporary test track had been marked out, while in a small part of the kilometre-long terminal building, various displays gave glimpses into Audi’s alternative energy plans.
Cutaway versions of the R8 e-tron show it to be almost Formula One standard in terms of attention to weight-saving detail. Most of the body is carbon-fibre – even the suspension springs are made of a composite plastic – to compensate for the giant 550 kilogram battery pack needed to produce its stunning get-up-and-go.
Clever tech includes active wheel covers that close at speed to lower air resistance, and a virtual rear view mirror in the centre. This uses a camera, saving on a glass screen at the rear, and helping limit the all-up weight to 1780 kilograms (that’s still 200 kilograms more than the V10 R8).
The interior is similar to the normal R8, though simplified. The familiar exterior shape is an illusion. Every body panel except the door skins is unique to this car; only nine of 6000 parts are shared between R8 and R8 e-tron.
Ten examples have been built, all in bright orange, with exposed carbon-fibre “sideblades”.
The car is two-wheel drive, forgoing Audi’s hallmark quattro system (again to save weight).
On the marked-out track, the car could be flung from a standing start to about 120 km/h before the first corner. It is restricted to 200 km/h, though the limiter was removed for the Nurburgring lap record and the car hit 255 km/h.
The acceleration is wild, though not silent. Aside from the noise that comes with putting 280 kilowatts through the rear tyres, there is an engine whirr. It comes through the sound system, however. It’s synthesised, to give a sportier feel.
From that first corner it was mainly a handling track, but with sufficient short straights to demonstrate the e-tron’s massive torque. This torque negates the need for a gearbox.
During cornering, tyre noise is by far the loudest sound (the synthetic engine noise cuts out at 60km/h). The central screen allows you to adjust the driving dynamics from “efficiency” through to “dynamic” and “automatic” (which toggles between the two depending on your driving).
It is very easy to control, with excellent turn-in, particularly when the vectoring system gives extra torque to the outside rear wheel during cornering (it cuts out in “efficiency” mode to save the batteries).
Massive stopping power, and regenerative braking, are provided by the large composite ceramic brake rotors. Again the lack of engine noise is a problem – the rubbing of pad on brake is so loud you’d swear there is damage being done.
The R8 e-tron is beautifully made and a delight to drive, but is there a market for such an expensive supercar with such a limited range? Audi doesn’t think so, not until batteries are lighter, cheaper and hold more charge.
The solution? It may well be a smaller, lower performance electric car with fewer batteries and a small petrol (or diesel) engine in reserve.
Hence, the chance to drive the e-tron A1.
This small hatch has been built in low volume for testing in German cities and is a precursor to an A3 e-tron production vehicle, which will go on sale in Europe next year and in Australia in 2015.
The A3 has a conventional engine in its nose, but the A1 has a tiny Wankel rotary in its tail. Why use a Wankel, famous for its high fuel use? Because the idea is not to use it. Consider it an emergency life raft if you run out of charge. It is not connected to the wheels, it’s there to recharge the batteries. And being a Wankel, it is very compact for its power output.
Most commuters should be able to do their daily drive within the 50 kilometre range of the batteries, and plug in overnight.
There is an eerie silence when you push the start button, but beyond that it feels much like a conventional, if slightly heavy, small hatch to drive. There is no trouble keeping up with city traffic: the motor develops 85 kilowatts and 300 Newton metres; 0-100km/h takes 9.8 seconds.
The cabin is unaffected by battery placement and even the boot is a reasonable size, despite there being an engine under it. There are few other compromises, other than the probability of a highly elevated purchase price.
After half an hour of driving in Berlin traffic, the display told me I had 19 kilometres left on the batteries. There was no need for “range anxiety” however, as total range is 250 kilometres overall, thanks to the Wankel engine and its small fuel tank.
Tony Davis tested these cars in Europe as a guest of Audi