Bugatti Chiron Passes 300-MPH Barrier with 304-MPH Run, Sets World Record

© Bugatti   Driver Andy Wallace talks C/D through the fastest run.

By Mike Duff, Car and Driver

• Factory test driver Andy Wallace piloted a slightly modified Bugatti Chiron to an official 304.773 mph at the Ehra-Lessien test track in Germany.

• The car has a slightly more powerful version of the Chiron's quad-turbo W-15 tuned to 1600 horsepower.

• Wallace tells C/D all the details of this record-setting run.

Ever since the Bugatti Chiron was launched, with a 261-mph speed limiter, we've been desperate to know what it could manage if let off the leash. Now Bugatti has done that at the vast Ehra-Lessien test track in Germany; the car smashed both the production-car record and the 300-mph barrier. 

Factory test driver Andy Wallace, who previously set production-car records in both the Jaguar XJ220 and the McLaren F1, drove a slightly modified Chiron to a time, certified by the German TÜV organization, of 304.773 mph.

Bugatti Chiron Goes 304 MPH

The Chiron used was in what is described by Bugatti as "near production" spec, modified with an additional safety cell and with aerodynamic changes and higher seventh-gear ratios, which we believe will be incorporated into a celebratory limited-edition model. It also used a slightly more powerful version of the regular Chiron's quad-turbocharged W-16 engine, turned up to produce 1600 hp, the same total made by the recently announced Centodieci.

The record was set in conjunction with Italian constructor Dallara, which makes the Chiron's body and developed the aerodynamic kit, and also Michelin which created the very special tires capable of dealing with such huge forces, rotating up to 4100 times a minute. The specially constructed Michelin Pilot Cup 2 tires were all X-rayed before being selected for use on the car.

"Inside the tires you've got these thin metal strands that go radially around the edge and which are sort of equidistant from each other," Wallace explained, when C/D spoke to him after the record run. "On quite a lot of tires there are one or two spots where these strands touch. It's not normally a problem, certainly not at the mandated speed limit, but when you start to go really fast with the huge gravitational force it's possible to get movement there, and temperature."

The 58-year-old British sports-car veteran and the team built up to the record speed over the course of more than a week, gradually increasing speeds to ensure that the car behaved according to the aerodynamic predictions and that lift and downforce were balanced. Yet that still meant huge forces running through the structure of the Chiron, as Wallace explains: “Zero net downforce front and rear sounds easy, as you've got the static weight of the car pushing down and that's more than heavy enough. But it doesn't mean the air is having no effect, it means there is close to 2000 kg [4409 pounds] on the top surface of the body trying to pick the car off the ground and another 2000 kg under the car trying to pull it back down: two fighting forces that come to four tons roughly, trying to separate the car. So you've got to be absolutely sure that everything on the car is secure enough to go this fast."

The other challenge was the gyroscopic effect created by the huge rotational speeds of the tires, something Wallace says only really begins to affect a car traveling at this huge speed. “At 200 mph you can barely feel it, but at 300 mph it's absolutely enormous,” said Wallace. "It's felt mostly on the front wheels and therefore the steering, like a spinning top when it starts to move it wants to continue to move."

© Bugatti   Bugatti Chiron Goes 304 MPH

"Any Crash at That Sort of Speed Is Likely to Hurt"

As the Chiron increased speed, other unexpected challenges arrived. "They had resurfaced one end of the track at Ehra, and once you come down off the banking you're building up speed on the 8.8-km straight," he remembered, "then at exactly 447 km/h (277 mph) the car would go from the new surface to the old surface, and I got to calling this "the jump"—it’s a bump that you'd barely notice in a normal car, but at those speeds it feels huge . . . If you go over that and land and there’s a bit of a sidewind, then you can lose feeling and suddenly lose confidence."

Trust being the most important commodity for any driver attempting such high speeds, even with the Chiron's safety gear, a freshly swept track and on-site medical intervention. "Any crash at that sort of speed is likely to hurt," Wallace admitted, deadpan. "I had a massive amount of trust in all the engineers and a lot of respect for all of them, likewise with Dallara and Michelin . . . when the project started we sat down and went through the risks, drawing a pyramid with the big ones at the bottom and trying to work out ways to eliminate them. But you can never get rid of them completely, and at the top you've still got "sod's law"—something you just can’t control. If you did this enough times, it would get you, but if you trust the people you're working with, which I did 100 percent, then in the end you just do it."

After four days at Ehra-Lessien, the team had managed a peak speed of 482.5 km/h—299.8 mph—but was determined to break the 300-mph barrier. On what turned out to be the record-setting lap, Wallace remembers feeling more confident as the car went over "the jump"—"after it landed and had a bit of a weave about I thought it's the best it's been, the cross wind was a little bit less and I just kept it pinned. The strange thing is that there's a radar speed display half way down the straight but it's obviously never been calibrated for something that fast—I went past it and it flashed up 502 km/h (312 mph), but then I looked at my gauge and it was only doing 476 km/h (296 mph) on the GPS. So I kept my foot in and saw it get past 490 km/h (304 mph), but I was running short on room."

Ehra-Lessien's three-sided layout uses banked corners, with a speed limit of 200 km/h (124 mph) for the south bend at the end of the longest straight. "It's quite tricky to spot your braking point when you're doing 136 meters (446 feet) per second," Wallace admitted. "Then you have to slow down gently so you don't shift the aero too much and lose control of the car, when all your instincts are telling you to stand on the brake."

The Chiron went so fast on its record run that the telemetry system relaying time to the team couldn't keep up. For several minutes, Wallace was the only one who knew the record had fallen. "I saw the speed on the GPS and I was thanking everyone on the way back to the pit area over the radio," he said. "They couldn't work out why I was so happy—the fastest they'd seen was 479 km/h and we'd already done 482.5 km/h. Then I stop and they all dove into the recording equipment on the car and looked through it, found the speed, and they all went mental."

If it hadn't been for running out of space on the world's longest test-track straight, the Chiron could even have gone slightly quicker. "The speed trace hadn't leveled out, it was still climbing," Wallace says. Ehra-Lessien's position at just 165 feet above sea level also means the air is relatively dense: at higher altitudes the car would encounter less resistance. But while others may eventually go quicker, Bugatti has decided to drop the mic on record setting. The company confirmed it will "withdraw from the competition to produce the fastest serial-production cars."

"Bugatti Will Go Down in the History Books"

"We have shown several times that we built the fastest cars in the world. In future we will focus on other areas," said Stefan Winkelmann in the official release on the record. "Bugatti was the first to exceed 300 mph. Its name will go down in the history books, and it will stay that way forever."

As for Wallace, where does reacquiring the world production record sit in the list of career highlights of a former Le Mans and Daytona winner?

“A lot of people will just say 'You drove a Bugatti at 300 mph; whoever you put in it could have done that,' and maybe that's even true,” he said. "If you win at Le Mans or Daytona, then there's a lot more of what you were doing was down to the driver, I'm well aware of that. But when I think about it, it's pretty bloody cool. If somebody said to me even two years ago that I was going to go over 300 mph, I'd have thought they were out of their mind.”

Wallace also noted one interesting side effect from the record setting. "I spent the next week after doing the run driving around really slowly and being quite happy; I was doing 10 or 15 mph under the speed limit everywhere."