Saturday, February 15, 2025

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Reviving Audi’s long lost rally car.

What is the Audi Quattro RS001

The Audi Quattro RS001 remains one of motorsport’s biggest mysteries. A mid-engine prototype car built during the legendary 1980s era of Group B rally for the new Group S class that was set to follow. On a secret test day, a photographer captured a glimpse of the now famous Audi RS001 before it was destroyed and never seen again. A few black and white blurry photographs are all the evidence that was left. The Group S class was cancelled soon after.
EPS Motorsport’s Dave Rowe admired the mysterious story and decided that he would do the impossible by building a car that never truly came to light.

How do you build a top secret prototype?

Dave began his project by creating a diecast model as a starting point for his vision. Following this, he then had the photos of the car scanned to create a 3D model of the car which led to the body and chassis design. This was the basis to start building the car. A crucial next step in the process was solving the complexity of the driveline. As the car was unique, no off the shelf solution was available. Dave engineered a custom driveline system utilising bespoke differentials and gearbox. These innovations were essential to bringing the project to life.

Car specs

The car is made from a chromoly frame, paired with a custom body that was designed from a 3D model, resulting in a weight of only 1001 kgs. At the heart lies an Audi 5 Cylinder 2.5L engine originally from a TTRS, with an upgraded TurboSmart turbocharger. On the dyno, this setup delivered an impressive 756 horsepower to the flywheel.

Dave opted for the EPS custom 6 speed transmission and differential system to connect the mid-engine all-wheel drive system. The car has KW suspension, along with Alcon brakes paired with a Bosch Motorsport ABS system.

It also features a full suite of MoTeC electronics.

How do the MoTeC electronics integrate?

M150 ECU & GPRP Pro firmware

At the core of the MoTeC system is an M150 ECU running our GPRP Pro Package. GPRP Pro is a sophisticated engine control firmware centred around calculating and controlling engine torque via throttle opening and ignition control.
On the Pro platform, Dave’s Audi benefits from advanced traction control, greater configurability for knock control and much more.

PDM15 & PDM30

MoTeC Power Distribution Modules are located in the front and rear of the Audi, providing programmable control of the car’s power from nose to tail. In the rear, a PDM15 powers all engine ECU components, rear lights, a MoTeC 15 button keypad and a separate 4 button keypad.
The 15 button keypad is located in the cabin controlling all aspects of the car, while the smaller keypad is positioned in the rear for ease of servicing.
The front PDM30 powers the dash, ABS, lights, fans, fuel pumps, headlights, heated windscreen and power steering. The system is connected via CAN, maximising flexibility and minimising wiring.

C185 Display Logger

Paying homage to the original prototype, the Audi uses mechanical instrumentation, however, the brains behind these gauges comes from a hidden C185 Display Logger. With Dave’s clever MoTeC know-how, the ECU transmits sensor data to the dash, which utilises the output function to transfer these into a signal that drives the gauges.

What are the plans for the car?

When we asked Dave what he had in store, he confidently said racing Pikes Peak was at the top of the list. This is not his first attempt at the mountain; he has raced the event 4 times, twice in his Mitsubishi EVO 9RS and twice in his Audi Quattro S1 named “Ray”. Dave will be filming a YouTube series documenting the process of entering for Pikes Peak, shipping the car and racing the event.

Build series

Spread out into 18 YouTube episodes, Dave has recorded the whole process of building “Grumpy”, showcasing the project from the photo inspiration to a working race car. So sit down, grab some popcorn and learn about this phenomenal build.

Via: MoTeC

Gabe Balch
Gabe Balch
The automobile and its stories captivated him from birth and the freedom, expression, and personal bonds they enable continue to serve as inspiration. His inquisitive nature explores the how of the machines themselves, and the unique minds behind the creations. As a world traveler he longs for the open road, or better yet, the last signs of pavement.