Measuring and Verifying Speed Records of Rimac Nevera Electric Hypercar

Silence, just ambient sounds - a light breeze rustling nearby foliage and distant birdsong. Then, a short, sudden whoosh, a sound like the rush of wind through a tunnel or a jet engine. The aerodynamic disturbance caused by the Nevera at maximum speed. From a distance of 70 meters, we watch the car zooming by.  

The competition for the world’s fastest production car has been fierce in recent years, and champions are crowned by just a few tenths of a second. In April, RIMAC put its Nevera to the test. The task? To attempt setting the most performance records broken for a car in one day.

The Croatian automotive manufacturer Bugatti Rimac, led by CEO Mate Rimac, designs and manufactures the Nevera under the Rimac Automobili brand. The Rimac Group is developing high-performance electrification, electronics, and software solutions for the world’s largest OEMs. Based on the outskirts of Zagreb, Croatia, with locations around Europe, Rimac currently employs more than 2,000 people. Bringing together the most advanced hypercars in the world, the Rimac Group is the majority shareholder of Bugatti Rimac and the sole stakeholder of Rimac Technology.

Attempt for new world records

In November 2022, the Rimac Nevera set a top speed of 412kph (258mph), making it the fastest electric production car in the world. April this year, the RIMAC engineers set out to test their vehicle to the limits and make a series of speed, acceleration, and braking records - new world records for production cars. 

Dewesoft and Racelogic were there to measure and independently verify the Nevera achievements. Based in Buckingham, United Kingdom, Racelogic designs and manufactures electronic systems to measure, record, display, analyze, and simulate data from moving vehicles specializing in equipment and applications used in vehicle testing and motorsport. 

At the Papenburg proving ground, the company’s application engineer measured with the Racelogic VBOX system, which internationally is recognized as a quality standard in speed measurement, braking distance measurement, vehicle dynamics, and tire testing.

To accurately measure the attempted speed and acceleration records of the Rimac Nevera electric supercar, we from Dewesoft utilized our data acquisition equipment and software. With this, we could instrument the vehicle and gather and process precise data on its performance. Our results reveal and document the impressive speed and acceleration capabilities of the Nevera. 

The electric hypercar - Rimac Nevera

The Rimac Nevera is an all-electric hypercar that pushes the boundaries of performance, technology, and sustainability. Rimac released the first Nevera production prototype in August 2021. Having completed crash testing for homologation, Rimac delivered the first Neveras to customers in mid-2022. 

Nevera production is limited to 150 examples, and the car is currently being built on the outskirts of Zagreb. Each vehicle is hand-built with meticulous attention to detail and craftsmanship, ensuring quality and exclusivity. The Nevera is based on the same platform, manufactured in the same factory, and at the same rate as the Italian sports car Pininfarina Battista.

Named after a quick, sudden, and mighty Mediterranean storm that races across the open sea of Croatia, the Nevera is extremely powerful. The aerodynamic exterior design combines carbon fiber and other lightweight materials crafted to maximize performance and aesthetics. Its sleek, low-slung profile and flowing lines exude a sense of speed and dynamism. 

The Rimac Nevera specs

The electric powertrain with an all-wheel-drive system sets the Nevera apart. For control and agility, it features an individual electric motor for each wheel. Together they generate 1,914 horsepower (1,408 kW) and 2,360 Nm of torque! For precise power distribution, enhanced traction, and exceptional handling, the software calculates the torque deployed to each wheel over 100 times a second.

The Nevera is equipped with a cutting-edge battery pack, an advanced lithium-ion battery with a capacity of 120 kWh. That’s enough energy for high-speed driving and extended range. Rimac claims an impressive electric range of 550 kilometres, approximately 340 miles. 

The car’s cockpit is stocked up with high-tech, featuring a driver-focused layout with a digital instrument cluster and a large central infotainment screen. It incorporates a suite of advanced driver-assistance systems, including adaptive cruise control, collision avoidance, and lane-keeping assist. 

The Papenburg tracks

A sunny weekend in April, stretching out before us is a vast expanse of tarmac. A perfectly circular track that seems to go on endlessly. The high-speed oval at Papenburg proving ground is designed to push vehicles to their limits and provide an environment for testing high-speed capabilities. 

Located in Niedersachsen in the northwest of Germany, Automotive Testing Papenburg GmbH (ATP) is independent of manufacturers and operates one of the world’s largest automotive proving grounds. The complete area covers about 780 ha (7.8 km2). The area is so huge that the vehicles tested are only visible for short distances while passing you.

ATP provides 75 km of test tracks for comprehensive vehicle and component tests with passenger and commercial vehicles. The proving ground included:

• high-speed oval track,

• vehicle dynamics area,

• handling track

• braking tracks,

• acoustic track

• durability roads, and 

• several more.

The Nevera acceleration, braking, and speed tests were performed on ATP’s high-speed oval track. 

The oval's layout consists of two long, parallel straights connected by two semi-circular banked turns, forming an elongated loop. A 12.3 km long round track with banked curves up to 49.7° providing zero side force up to 250 km/h. Running east and west the oval’s straights are each 4.0 km with five lanes, while its curves in the north and south are each 2.15 km with five lanes. It’s a full-throttle track, perfect for testing top speeds!

The measurement setup

Three teams feathered on the side - Rimac, Racelogic, and Dewesoft. From our side, the team included two colleagues from marketing, Primož Rome and Luka Knez, Automotive Application Engineer Matjaž Strniša, and myself.

We used two measurement setups based on our DAQ system. One to monitor the vehicle’s position, acceleration, speed, and braking and one to test its aerodynamics.

The primary purpose of the DAQ system was to measure and document the record attempts. While measuring speed and time we could determine its acceleration and braking parameters.

However, the time on a test track is precious. The Rimac team also used the proving ground to measure and tune the active aerodynamics of the Nevera.

Our data acquisition system measured the vehicle’s position, orientation, velocity, acceleration, and angular rates. In parallel, it also acquired data from two Nevera’s CAN networks, suspension travel, and vehicle ride heights on four corners of the vehicle. 

DewesoftX data acquisition software acquired the data and calculated the records with its Brake Test module.

The equipment used

Data acquisition system

• MINITAURs: Data processing computer for data storage, cameras connection, and LTE connection using Teltonika RUT 240 LTE modem. The system was also equipped with a secondary internal 100 Hz GNSS receiver for backup next to Navion INS.

• SIRIUSi-8xCAN: Used for CAN bus acquisition for the body (wing positions, pumps for hydraulics, speed) and safety.

• DEWE-43A: Analog data acquisition system was used for acquisition from position laser sensors and suspension force.

• NAVION i2: Inertial navigation system (INS) used to precisely measure a vehicle’s speed, position, acceleration, and heading.

• DS-DISP-12: In-car mounted display with a front windshield mount for data overview.

• DS-BP2: Battery pack used as the single power source for the measurement system.

• DS-REM-CTRL: Remote control for controlling the measurement (start/stop/store).

• Racelogic VBOX and VBOX video: Secondary validation system.

NAVION is a Dewesoft inertial navigation system platform for accurate position, orientation, velocity, and acceleration measurements. A Kalman-based algorithm combines GNSS positioning with the measurements provided by a MEMS-based inertial measurement unit. 

Sensors

• Four LVDT sensors: Each installed on the four suspension springs and measures aerodynamic loads on the vehicle. Used for the aerodynamics team for the correct calibration and setup of aerodynamics.

• Four laser distance sensors: For measurement of the vertical position of the car to the tarmac surface. Used for the aerodynamics team for the correct calibration and setup of aerodynamics.

• Video cameras: Logitech USB camera.

Software

• DewesoftX 2023.2

• DewesoftX brake test module

• DS-REM-CTRL control module for start/stop/store

• Math modules

• Slip of the driven wheels RR, RL, FR, FL: comparing vehicle wheel speed with the true velocity of the vehicle

• Running averages (last 2 seconds): the sum of front and rear downforce forces - FL_force, FR_force, RL/RR_force). measured with LVDT potentiometers on the suspension.

The Brake Test module is a software tool to automate brake and acceleration testing. It calculates and stores test results like MFDD, stopping time and distance, and provides driver guidance. The software enables different start/stop options, e.g., speed or brake pedal switch.

We meticulously arrange and calibrate our equipment. Any miscalculation or error in setup could jeopardize the accuracy of the record attempt. We carefully route cables, test and calibrate sensors, and double-check the data acquisition systems for accuracy. Every detail was scrutinized to ensure measurement reliability.

During test runs, we had our system connected to a remote desktop. This setup enabled us to do remote telemetry. The engineers could monitor the main parameters of the vehicle and acceleration and braking numbers. The results, world records, could be seen in the making. The powerful 3D Map visualization also enabled us to follow the car on the track during the test. 

The aerodynamics test

The first day runs were dedicated to the aerodynamics testing, system shakedown, and some preliminary acceleration test runs. The purpose of aerodynamics tests was to confirm models based on simulations by measuring the downforce at different settings of the vehicle’s aerodynamic surfaces. 

The Rimac Nevera has two movable aerodynamic surfaces. The flap on the front and the rear wing. Vehicle electronics control both flaps, and the communication between the control ECU and actuators go via CAN. The front flap can be positioned at different angles, and the rear wing can be set at various heights and angles of attack. 

We used the DEWE-43A data acquidition system for powering and acquiring data for the laser distance sensors to ensure sufficient power. The sensor measured the vehicle’s front and rear ride height. We calculated the aerodynamic downforce by measuring the damper displacement with four LVDT sensors installed on the four suspension springs. The measurements are used by the Rimac aerodynamics team to ensure correct calibration and setup of the vehicle’s aerodynamics.

The relation between damper displacement and wheel load was calibrated in the workshop. The method works well for straight-line tests at a constant velocity where there are minimal load changes from weight transfer. The load changes caused by the uneven track are reduced by averaging the loads over a fixed window. 

During the test, an aerodynamics specialist in the vehicle’s passenger seat went through different front and rear settings by sending the commands via Rimac control software. The parameters were decoded from the vehicle CAN network and stored alongside the velocity and suspension displacements. 

Acceleration, speed, and braking measurements

The main purpose of going to ATP was to break acceleration and braking records. After the aerodynamic testing, the car did preliminary runs for the Rimac engineers to check if it was performing as it should. Especially, how the powertrain was working. 

The electric powertrain in Rimac Nevera is crucial for acceleration and braking performance. The car is overpowered and can spin the wheels up to about 175 km/h (108 mph). The tire slip is controlled electronically to ensure as much traction as possible, and the system has to adapt to the surface and the tires.

Part of the braking power is provided by regenerative braking, which reduces the energy required on the brake disc, pad, and calipers. The braking system can be lighter, and some of the energy applied can be recovered. 

To achieve new records, the powertrain had to work correctly. With the measurement system, we monitored the times achieved in these preliminary runs and could also see some of the world records already beaten. The initial tests also served us to check that our calculations of times and distances were correct. Every detail matters, and there is an intense focus on precision. 

The main runs were something else. As exclusive time slots on the track are limited, everything had to come together at the right time. The technicians check the car. Test engineers determine the character of the next run. The driver gets ready. And we check that our system measures everything.

The driver goes out onto the track. We are standing around 70 m away from one of the straights. As the car drives off, we start looking at the laptop screen remotely connected to the measurement system. We can monitor the car’s speed, acceleration, braking times, and position on the track in real time. We can see when the driver goes through the ovals or prepares the tires by making curves on the straight. We can see the acceleration and brake run. 

In each run, we observe the numbers. We mostly remembered the record from the previous 0-60 mph run and immediately learn if this run was better. It’s fascinating how fast the car is and how effortlessly it goes to 400 km/h and beyond. 

The results - 23 new records

Measuring Results: Rimac Nevera World Records

The Dewesoft test report contains minimum values of acceleration and braking parameters.

At Papenburg, Rimac Nevera EV set 23 records. Zero to 400 km/h and back again in under 30 seconds. 29.94 to be exact. And that was just one of them. The previous record was set in 2019 by a Koenigsegg Regera accelerating from 0 to 400 km/h and back to 0 in 31.49 seconds at Råda Airfield close to Lidköping in Sweden.

Widely regarded as the ultimate test of hypercar straight-line performance, the 0-400-0 km/h (0-249-0 mph) run tests acceleration, aerodynamics, top speed, and stopping power. And now the Nevera is the undisputed hypercar champion, with a new record time of 29.93 seconds. That is 1.5 seconds quicker than the previous holder.

In February this year, the Pininfarina Battista registered a quarter-mile time of 8.55 seconds. Beating the Rimac Nevera, which did 8.58 in April 2021. The fully electric Battista covered the half-mile distance in 13.38 seconds at Indore’s Natrax facility in India. Both records, now again, belong to the Rimac Nevera with respectively 8.26 and 12.83 seconds. 

Conclusion

After the runs, we quickly extracted each data file and checked the values for a few essential records. We then transferred the measurement files for the final checks. With the list of all records attempted, we went through the data. Rimac attempted to break 23 world records. We measured the runs and we, as well as Racelogic, could confirm the new records.

All acceleration records were completed with a standard one-foot rollout and equipped with road-legal Michelin Cup 2 R tires on non-prepped asphalt. Acceleration times from standstill were measured after 1 ft (0.3048 m) of rollout after detecting movement with a total velocity exceeding the threshold of 0.8 km/h.

We measured the time, velocity, and position with our inertial navigation system and a backup GNSS system. Navion i2 INS was connected to the MINITAURs. It ensured accurate position, orientation, velocity, and acceleration data. We acquired all measurements and calculated all results with DewesoftX 2023.2 data acquisition software.

Stop-of-movement times in brake/deceleration measurements were calculated by extrapolating the total velocity to zero with measurement samples before and right after the total velocity measurement is below or equal to 0.8 km/h.

When setting up measurement equipment for the validation of a world speed record, there is undeniably a mix of excitement and nervousness. Time was short, and the stakes were high but it all worked out perfectly.