Audi E-tron R4: Full Details

Audi’s latest e-tron concept is the strongest hint yet at the firm’s intentions to build a smaller, lighter sports car known as R4.

The new two-seater has the same name as the bigger, more powerful wheel motor equipped All Wheel Drive version. However, this car is significantly smaller and, uncharacteristically for an Audi concept car with clear sporting intentions, it’s rear-wheel drive.

The latest e-tron, revealed at the Detroit motor show, is also more than just a one-off showcase for Audi’s zero-emissions plans; it confirms that Audi chairman Rupert Stadler has already given the go-ahead for a new, small, mid-engined sports car.

According to Audi sources, this new e-tron concept provides strong clues to a new production car that will be sold as the R4. It will share key components with the showroom version of Volkswagen’s BlueSport concept, and possibly a new entry-level Porsche roadster, when it arrives in showrooms sometime between now and the end of 2013.

Picking up on the styling theme from the first e-tron, the low-slung concept has a traditional sports car silhouette, with a long bonnet, a heavily curved roofline and a stubby rear end. However, the body is a lot edgier, with hard crease lines, taut surfacing and a heavily sculpted rear end providing it with a highly contemporary look that sets the tone for the upcoming R4.

Elements such as a large single-frame grille housing carbonfibre fins to direct air into the front end, and distinctive LED-enhanced headlamp graphics, clearly set the new car out as an Audi from the front. However, certain features at the rear end are highly reminiscent of recent Aston Martin models — in particular the rear light graphic.

Styled by a small team working under Audi’s British-born manager for concept car design, Steve Lewis, this e-tron was completed in just four months following a go-ahead from senior management last September.

“We wanted to push the electric car in a sporty direction without making it appear too futuristic,” said Lewis. “It was important to give the car a uniquely technical appearance in a bid to get across the message of the electrical package that lies beneath.”

At 3930mm long, 1780mm wide and 1220mm tall, the concept is shorter, narrower and lower than the original e-tron and the current TT. It rides on a wheelbase that, at 2430mm, is 170mm shorter.

At the heart of the e-tron is a new electric powertrain. It uses a pair of motors mounted within the rear axle producing a total of 201bhp along with a whopping 1954lb ft of torque — all of which is sent to the rear wheels only via a torque-vectoring software differential.

Official performance figures put the sprint from 0-62mph at 5.9sec and 37-75mph (60-120km/h) at just 5.1sec, but the top speed is limited to just 124mph to conserve battery life.

Electrical energy is drawn from a bank of lithium ion batteries mounted behind the cabin in a space that, on production versions of the new R4, will be occupied by the engines. These are likely to include Audi’s 335bhp turbocharged 2.5-litre five-cylinder unit, which, Autocar has been told, could easily be packaged in the mid-engined slot.

Weighing a total of 399kg, the mid-mounted batteries have a capacity of 45kWh, or 2.6kWh more than the earlier e-tron. Fully charged, the concept’s range is put at 155 miles. Recharging takes 11 hours on a 230V system but on a 400V system this figure drops to just two hours.

As with the earlier R8-based e-tron, the R4-based version features an aluminium spaceframe to which Audi’s designers have attached body panels fashioned from carbonfibre-reinforced plastic. It’s an exotic combination that helps to provide the car with a kerb weight of just 1350kg, although at this stage it is unclear if the production version of the R4 will follow the same route.

With much of the weight concentrated at the rear, weight distribution is put at 40 per cent front/60 per cent rear, giving the concept — in the words of Audi R&D boss Michael Dick — “all the driveability of a go-kart — agile and neutral right up to the limit”.

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