Last month, Audi confirmed a more ‘realistic’ range of ~250 miles for its upcoming e-tron quattro all-electric SUV, which is expected to enter production later this year.

Now the German automaker reveals more details about the vehicle aerodynamic performance, which is an important part of the reason why it can achieve a significant range.

When unveiling the quattro concept back in 2015, Audi claimed: “the best drag aero performance for an SUV” with a drag coefficient of 0.25.

But weeks later, Tesla unveiled the production version of the Model X, which claimed a drag coefficient of 0.24 – narrowly beating the quattro.

Today, the four ring automaker talked about putting the latest quattro prototype in the Wind Tunnel Center in Ingolstadt:

“In front of the low-noise rotor measuring around five meters (16.4 ft) in diameter, the Audi e-tron prototype stares into the eye of the hurricane. On the aeroacoustics test rig in the Wind Tunnel Center in Ingolstadt, the world’s quietest vehicle wind tunnel, the Audi engineers optimize drag and noise under extreme conditions. Both are crucial for a car’s efficiency and comfort. With an output of 2.6 megawatts, the fan produces speeds of up to 300 km/h (186.4 mph). The Audi e-tron prototype was put through over 1,000 hours of testing here.”

They say that the result is “a drag coefficient of 0.28,” which is less aerodynamic than what they announced for the concept version in 2015.

Nonetheless, Audi claims that advances in aerodynamic on the vehicle have resulted in “around 35 kilometers (21.7 mi)” of additional range.

They wrote:

“To achieve the drag coefficient of 0.28, the Audi engineers developed a wide range of aerodynamics measures in all body areas. Some of these technical solutions are evident at first glance, while others fulfill their purpose hidden away from sight. Thanks to these solutions, the drag coefficient for the Audi e-tron prototype is almost 0.07 less than for a comparable, conventionally powered vehicle. With a typical usage profile this set-up increases the range by around 35 kilometers (21.7 mi) per battery charge in the WLTP cycle.”

Here are a few images of the e-tron quattro prototype in the wind tunnel:

In order to achieve those results, they had to make several changes and not all of them will be available on the stock vehicle.

For example, Audi is introducing what it calls “virtual exterior mirrors”, which consists of replacing the mirrors with cameras that will display what they see on OLED displays in the transition between the instrument panel and door.

That results in a much smaller extrusion outside of the cabin, which reduces drag and wind noise, but it is not something that is legal in all markets yet.

Audi will be offering it as an option where it legally can.

The e-tron quattro is also equipped with an air suspension that can lower at higher speeds in order to reduce drag and it is equipped with “controllable cool-air inlet.”

The controllable cool-air inlet – a frame behind the Singleframe with two electrically operated louvers – also helps lower drag. When shut, the air in this area flows with virtually no swirl. As soon as the drivetrain components need cooling or the air conditioning condenser requires ventilation, the top louver opens first and then both louvers. When the hydraulic wheel brakes are subject to high loads, the controllable cool-air inlet opens and releases two ducts which channel the cooling air into the front wheel arches to the brakes.

The car is set to enter production at Audi’s carbon-neutral plant in Brussels in the next few months in order for deliveries to start in European markets at “the end of 2018.”

Last month, Audi said that the all-electric e-tron Quattro SUV will be ‘starting at ‘€80,000’ in Germany -(~€67,000 before VAT – or ~$78,000 USD).

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