The Bugatti Chiron has recently achieved the new speed record when a Chiron prepared for the occasion reached at the beginning of August 490,484 km/h (304,773 mph) in the test circuit of Ehra-Lessen, owned by the Volkswagen group.
While today many supercars, to say almost all, reach and exceed 300 km / h top speed, touching 500 km/h in a streetcar is not something so simple. There are so many factors to keep in mind that what they have accomplished in Bugatti is still an extraordinary feat. From the car itself at the altitude of the track
The maximum speed recorded by the Bugatti Chiron piloted by Andy Wallace of 490 km / h was made in a single pass. The Guinness Book of Records, for example, requires that two passes be made in order to validate the speed record. But that’s just the Guinness norm. The reality is that the car reached that speed and did so in a single pass for safety issues inherent in the test track.
There are four crucial factors when trying to achieve a record: the car, the track, the location, and the weather. “The four have to be the ideal and be perfectly prepared for everything to be coordinated. The only thing we can’t influence is the weather, “explains Stefan Ellrott, Bugatti Development Manager.
With 1,600 HP of power -use the version of the W16 8.0 liters that will equip the Bugatti Centodieci -, guaranteeing the safety of all those present, starting with the pilot, was a priority. The Ehra-Lessien test track in Lower Saxony is the only place where Bugatti was authorized to try.
The Ehra-Lessien circuit and its difficulties
The 21-kilometer track has three lanes and is bordered by crash barriers. In addition, at the north and south ends (where the two curved corners are located) there are two emergency teams. Special floor mats and brushes are used to clean the road before each test.
Come on, except the weather is a place where you can control almost everything. Except for the weather, of course. However, the people of Bugatti had to compose with a series of limitations inherent to the track when making the attempt.
The 21-kilometer track has three lanes and is bordered by crash barriers. In addition, at the north and south ends (where the two curved corners are located) there are two emergency teams. Special floor mats and brushes are used to clean the road before each test.
Come on, except the weather is a place where you can control almost everything. Except for the weather, of course. However, the people of Bugatti had to compose with a series of limitations inherent to the track when making the attempt.
The first of these is the altitude at which the Ehra-Lessien circuit is. Or rather, lack of altitude. And this track is only 50 meters above sea level. It seems unimportant, but the faster a car goes, the more important it is.
As explained in Bugatti, as the altitude above sea level increases, the air becomes less dense and the number of molecules in the air decreases per unit volume. The reason for this is because of the air masses of the upper layer act on the air masses of the lower layer. Simply, the upper layers press the lower layers and therefore, the closer we are to sea level, the more atmospheric pressure there will be.
At sea level, the atmospheric pressure is 1013.25 hPa. Air pressure drops approximately 1 hPa every 8 meters: at 1,000 meters it is only about 88% of what is at sea level, about 890 hPa. “However, an exact mathematical description of the pressure curve is not possible due to the dynamics of the weather and other factors,” explained Bugatti.
As the air pressure and its density decrease, so does the aerodynamic drag. At higher altitude, cars or airplanes require less power to advance. At an altitude of 5,000 meters, the density falls approximately in half with respect to sea level, reducing air resistance by half. In other words, the car has to apply more force at sea level to advance than if it were traveling at an altitude of about 1,000 meters.
There are other factors to take into account, such as the Reynolds number (a dimensionless number used in fluid mechanics, reactor design and transport phenomena to characterize the movement of a fluid; its value indicates whether the flow follows a laminar or turbulent model ), the temperature and the amount of oxygen at that altitude (although with good turbos, they say in Bugatti that is not a problem).
In the end, however, it is in Bugatti, they have estimated that they would have been around 25 km / h faster in Nevada, according to Stefan Elliott. Nevada … where Koenigsegg achieved a Guinness speed record with Agera RS. He achieved an average 444.6 km / h, with a tip at 457 km / h. That is, in Bugatti, they believe that the Chiron, in Nevada, would have exceeded 500 km / h and that the Koenigsegg Agera RS, at sea level, would not have reached those 457 km / h.
In Bugatti, they believe that Chiron, in Nevada, would have exceeded 500 km / h and that Agera RS, at sea level, would not have reached those 457 km / h.
The Ehra-Lessien track has another factor that plays against Bugatti when making a speed record. According to Top Gear, in Bugatti, they realized that after years of cars rolling clockwise, making a pass in the opposite direction – as required in the Guinness Book of Records – the asphalt has a surface it would become overly abrasive in the opposite direction to almost 500 km/h. This would have caused an overheating of the tires and in Bugatti, they did not want to risk.
Andy Wallace, at the wheel
The pilot in charge of achieving the speed record is almost a regular record. It was none other than Andy Wallace who reached the maximum speed of exactly 490, 484 km / h (verified by SGS-TÜV Saar) on August 2, 2019. Andy Wallace is a British driver who won the 24 Hours of Le Mans in 1988, at the wheel of a Jaguar XJR-9LM.
He also won three class victories, two of them with Bentley (in 2001 and 2002). In addition, he won three times the 24 Hours of Daytona. Come on, who knows how to go fast. But perhaps he is more reminded of being the driver who took the McLaren F1 at 386.4 m / h (240.1 mph) thus setting a speed record for a production car that remained intact for 11 years. By the way, that record was also achieved on the Ehra-Lessien track.
After a lap to heat the Chiron, Andy Wallace accelerated leaving the north curve at 200 km / h to reach the maximum speed on the straight line of 8.8 kilometers. At the breaking point, defined precisely earlier, the Chiron slowed again at 200 km / h to take the southern curve. He had a distance of two kilometers to do so.
“I was a full-throttle from the beginning for about 70 seconds. For me, it was important to be out of the curve at 200 km / h to reach the maximum speed on the straight. That required the highest level of concentration, ”Wallace explained. It covered 136 meters in a second.
The speed record is the prelude to a new version of the Chiron
For the world record, a team of engineers from various disciplines, under the direction of Bugatti Development Chief Stefan Ellrott, “prepared a pre-production car for a Chiron derivative,” as explained in Bugatti. Implying, incidentally, that there will be a Chiron Super Sport “Long Tail” similar to this.
In case there are still doubts that there will be a serial version, to be a “preproduction car”, surprisingly it has a carbon fiber body in sight and two orange stripes that remind of the color combination of the Bugatti Veyron Super Sport. In addition to aerodynamic improvements, Bugatti attached great importance to safety. Andy Wallace’s seat was equipped with a six-point harness and the cabin had a safety cage.
The Bugatti team received support from Italian racing specialist Dallara (although Bugatti does not explain what role the Italian company played here), as well as the Michelin tire manufacturer. The Michelin high-speed tires that were already used in the Chiron were reinforced again, particularly the flanks so that they could handle forces of 5,300 G (each tire rotates 4,100 times in a minute) and all of it being approved for street use. And they are still Michelin Pilot Sport Cup 2.
Each Michelin Pilot Sport Cup 2 tire has to fit 5,300 G. Each wheel rotates at 4,100 rpm.
The tires underwent extensive testing in test benches at speeds of up to 511 km / h in the United States. Each tire was subjected to rigorous quality controls, both during and after its manufacture. They were also checked by X-rays to optimize even the smallest detail.
To prepare the record, Bugatti engineers tested the engine performance on the test bench and especially the interaction between the engine, the gearbox, and the chassis, making numerous simulations. Even the smallest changes have a great effect on this speed range. “After all the calculations and tests, we felt confident that the registry was within our reach,” explains Development Chief Stefan Ellrott with immense satisfaction.
It is not the first world record for Bugatti on this track with a Chiron. In 2017, former Formula 1 driver Juan Pablo Montoya drove a Chiron from 0 to 400 to 0 km / h on this test track in 41.96 seconds, the shortest race to that point. With the Veyron 16.4, Bugatti set speed records for production vehicles in 2005 and 2010, and in 2013 the Veyron Grand Sport Vitesse set the record as the fastest roadster in the world.