If innovation is electrifying and updating the iconic NSU Prinz 4

Trainees from Audi courses in mechatronics, bodywork, vehicle construction and painting proudly presented the "EP4"

NSU: the Audi “EP4” prototype derived from a 4 Prinz 1971
The historic NSU Prinz 4 was converted into the "EP4" by Audi apprentices at the Neckarsulm plant: the basis was provided by an almost forgotten 1971 model

The debut took place at the local "Family Day" of 2023.

On the occasion of the 150th anniversary of the construction of the Audi headquarters and plants in Neckarsulm in the German state of Baden-Württemberg, twelve apprentices of the House of the Four Rings have electrified an iconic classic car.

On 8 July, the apprentices of the automotive mechatronics, bodywork, vehicle construction and painting courses proudly presented the "EP4", the result of their painstaking work and youthful enthusiasm.

The “E” stands for “electric drive” and the “P4” for NSU Prinz 4, a model produced in the factory near Stuttgart by NSU Motorenwerke between 1961 and 1973.

“We wanted to build a car that not only looked good and was fast, but also honored the 150th anniversary of our industrial site”, explains Dean Scheuffler, an apprentice mechanic at the Audi works in Neckarsulm.

The starting point was perfect: a 4-built NSU Prinz 1971, which had been mostly forgotten and abandoned for decades until its resurrection in January 2023.

The apprentices have awakened this "princess" from her sleep with a virtual kiss and gifted her with a new high-voltage heart.

But the road was long, from the launch of the project at the beginning of the new year to the big reveal of "Family Day".

In numerous team meetings, apprentices, trainers and managers discussed the state of the art of the project, the challenges and the next steps to take.

The first task was to create a solid foundation for the conversion.

Mizgar Doman Hassan, apprentice body mechanic and vehicle construction, remember: “When we received the car, its cover had several rust spots. These areas were the first thing we fixed."

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NSU: the Audi “EP4” prototype derived from a 4 Prinz 1971
The electrified "EP4" is cooled through a large air intake located in the lower part of the bumper, while the heat can escape through a similar opening in the front hood

A 240 2020hp e-tron electric powertrain in place of the original petrol 2-cylinder

While budding body and paint specialists took care of the chassis and the external coating of the vehicle, the future auto mechanics worked on the propulsion unit, the battery and the yesteryear suspension.

In the back of the "princess", where a 30 HP (22 kiloWatt) two-cylinder petrol engine once resided, there is now a 240 HP (176 kW) electric motor.

The latter comes from a 2020 Audi e-tron and receives its energy from a battery from the plug-in hybrid model of the Audi Q7 TFSI e quattro.

The battery is located under the front hood, where the NSU Prinz once had the fuel tank.

La electrified car it is cooled through a large air intake located in the lower part of the bumper, while the heat can escape through a similar opening in the front hood.

The tailgate also improves cooling and can be fixed in the half-open position.

In doing so, it unveils its own "powerhouse" and is reminiscent of historic racing cars based on the sporty NSU Prinz 1000.

If at the time a row of open carburettors hinted at the sporting intentions of these made-in-Germany cars, now the "EP4" exhibits its electric heart.

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NSU: the Audi “EP4” prototype derived from a 4 Prinz 1971
On the "EP4" born from a NSU Prinz 4 a real twist: the wing is not fixed to the bodywork, as in other vehicles, but to the roll cage, and its supports consequently pass through the rear window

70s style, but with the rear wing fixed to the roll-cage and the modified floor pan of an Audi A1

It was clear to the apprentices that their “EP4” should proudly show that it was originally born as NSU Prinz.

The historical elements, therefore, do not only include the front and rear lights.

Even the 70s bodywork maintained the characteristic lines of the pillars and roof.

The apprentices they freed the sheet metal from rust and painted it in the Audi colors Suzuka Gray and Brilliant Black.

On the sides of the vehicle, adhesive stickers such as the wording "150" were applied, motivated by the anniversary of the factory.

The big leap in performance required extensive modifications to the chassis and the body.

The basis is the modified floor pan of an Audi A1 including brakes and axles.

The apprentices also applied a body extensively modified and greatly enlarged.

Its "muscular" fenders are unmistakably sporty.

The apprentices they designed them with the support of Audi Design and turned them into reality thanks to 3D printing.

The enlarged wheels of the car are hidden under the fenders.

Modern high-performance tires provide the necessary grip when accelerating and cornering.

“The eye travels with you! We wanted the performance of the 'EP4' to be visible from every angle”, explains Cynthia Huster, an apprentice painter.

The rear wing, painted in Signal Yellow color, gives the "EP4" a particularly sporty look.

The twist: the wing is not attached to the bodywork, as in other vehicles, but to the roll cage. Its supports, therefore, pass through the rear window.

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NSU: the Audi “EP4” prototype derived from a 4 Prinz 1971
Where a 4 HP (30 kW) two-cylinder petrol engine once resided on the NSU Prinz 22, the "EP4" prototype now features a 240 HP (176 kW) electric engine.

The interior: reduced to the essentials because it is typical of racing cars and in Signal Yellow colour

The safety cage in Signal Yellow creates a captivating contrast in the cockpit.

Apart from that, the interior (typical for racing cars) is reduced to the essentials; all other painted surfaces are black.

The occupants recline on “thoroughbred” bucket seats made of carbon fiber reinforced plastic “Recaro Podium”.

An on-board computer and its screen are used for the instrument cluster and display.

They also act as a speedometer and on-board computer of the vehicle, also performing vehicle diagnostic tasks.

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NSU: the Audi “EP4” prototype derived from a 4 Prinz 1971
The "muscular" fenders of the "EP4" are unmistakably sporty: the apprentices designed them with the support of Audi Design and transformed them into reality thanks to 3D printing

Timo Engler: “Young people tested 3D printing, but above all… played as a team”

At all stages, the apprentices put into practice the knowledge acquired during the training.

Timo Engler, responsible for training tech of Vehicles/Logistics of the Audi Group, explained that “The project gave our apprentices the opportunity to work freely with different techniques and with different materials. For example, in addition to the electric drive, they used 3D printing - a second technology of the future. Carbon fiber, which is already familiar from motorsports, was also used for the bonnet.”

Ma the apprentices they have not only learned a lot in terms of “artisanal” work, so to speak.

“In the case of 'EP4', the vision and deadlines to meet were very ambitious. It's nice to see how the young employees have grown a lot professionally with the task that has been entrusted to them and what a qualitative leap they have made overall, working 'as a team'…”.

Last but not least, the trainees were able to receive valuable advice and support at any time from Technical Development department by Audi.

In this way, they automatically learned a lot about the manufacturing processes of the House of the Four Rings and got to know various experts from other sectors of the company.

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NSU: the Audi “EP4” prototype derived from a 4 Prinz 1971
The “E” stands for “electric drive” and the “P4” for NSU Prinz 4, a model produced in the factory near Stuttgart by NSU Motorenwerke between 1961 and 1973

History and future: from the “Wirtschaftswunder” to Audi via Neckarsulmer Strickmaschinenfabrik

Whether symbols of the “Wirtschaftswunder”, the rapid reconstruction and the development of the economy of West Germany and Austria after the Second World War, or of "historic" racing cars that still today achieve victories in hill climbs, NSU vehicles have made history and continue to make history.

NSU Motorenwerke AG, NSU for short, was a German manufacturer of automobiles, motorcycles and pedal bicycles, founded in 1873 by the entrepreneur Christian Schmidt.

Acquired by the Volkswagen Group in 1969, the company was merged with Auto Union to create Audi NSU Auto Union AG, later simply Audi.

The name NSU was born as an abbreviation of the word "Neckarsulm", the city of the Kingdom of Württemberg where the "Neckarsulmer Strickmaschinenfabrik" was born in the pre-unification German age.

With its charm and its electric transmission, the “EP4” arouses anticipation for the next all-electric chapters of the Story of the Audi site in Neckarsulm.

Xavier Ros, member of the Audi Board of Management for the Human resources, was impressed by this unique project.

“With admirable effort and remarkable creativity, our apprentices have built an extraordinary car. They can be really proud of the result”, he has declared.

And he added: “Projects like this show that our company has a secure future thanks to our young talents”.

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NSU: the Audi “EP4” prototype derived from a 4 Prinz 1971
In 2023 the Audi Group, heir to NSU Motorenwerke AG, where "NSU" was the abbreviation of Neckarsulmer Strickmaschinenfabrik, celebrated the factory's 150th anniversary