11 crazy facts from Bugatti’s 300mph run

By topgear, 06 September 2019

1. 304.773mph 

Or, 490.484 km/h in Euro-speak. That’s the big number recorded by a sealed GPS box in the modified Chiron and the final top speed Andy Wallace managed on 2 August, becoming the first hypercar to break 482km/h. That’s over three times the top speed of a Suzuki Jimny. 

2. 50kph

The increments that part-time land pilot and full-time dude Andy made while attempting the record. He worked his way up to the top speed from 300km/h in these small steps to make sure all the conditions were right and the Chiron was optimally balanced in terms of lift and downforce.

“Even at the first attempt I felt this would work. The Chiron ran perfectly and the track and weather conditions were ideal,” Andy said after.

3. 136 metres in one second

That’s the ground the Chiron was covering per second at full-whack. Or one mile every 11.8 seconds. Or 8.2km a minute. See, after one lap to condition the Chiron, Wallace accelerated out of Ehra’s monster north curve to 190+km/h to reach top speed on the 8.7km straight. At a precisely defined braking point, he decelerated the Chiron back to 190km/h to drive through the opposing south bend. He had a distance of two kilometres in which to do so. Breezy.

4. 70 seconds 

How long Andy had the throttle pinned for. “I went at full throttle from the start for approximately 70 seconds. It was important for me to be out of the bend at 200 km/h in order to reach top speed on the straight. That required the very highest level of concentration.”

5. 98kph

How much faster the Chiron went than the McLaren F1 at Ehra back in 1998. Which, coincidentally, was also driven by Andy Wallace. See, Andy likes driving fast. And he’s rather good at it. The secret? Balls of tungsten carbide.

6. 1,578bhp

How much oomph was needed from the 8.0-litre, quad-turbo W16 unit – nicknamed Thor – to punch through the air at over 482km/h. In a testament to Bugatti’s engineering, the gearbox remained standard – as did the all-wheel-drive system.

7. 25cm

The record car’s growth spurt compared to a ‘normal’ Chiron. Its purposeful intent is amplified by laser-controlled ride height, set significantly lower to reduce drag, giving the impression that the car is melting into the tarmac. In addition to aerodynamic changes at the front, rear and side to reduce drag, the rear wing and airbrake have been removed and replaced with a static unit recessed into the tail.

8. 4,100

How many times the tyres rotate a minute. See, tyres have always been the limiting factor for high-speed runs. Michelin provided the boots for the 482km/h run, opting for a set of Michelin Sport Cup 2 tyres that had been reinforced with stronger metallic threads in the carcass. They were subjected to extensive test bench trials at speeds of up to 510km/h in the USA before the run, with each tyre being X-rayed to detect any air pockets or defects. Nobody wants a tyre whoopsie at over 482km/h as you’d need more than a dustpan and brush to clear it up.

9. 50 

The metres above sea level where Bugatti did the run. The 8.7km long straight is a smidge above sea level. Unlike higher-altitude high-speed tracks (or roads like the one used by Koenigsegg in Nevada) this has certain drawbacks. Due to the higher air density, the vehicle has to apply more force as at 482km/h it’s like driving against a concrete tower block. “Air pressure, air density and temperature are very important for high-speed driving and can make a difference of up to 25km/h, depending on the altitude,” says Bugatti boff Stefan Ellrott.

10. 25kph

How much faster Bugatti needed to go than Koenigsegg to hit 482km/h. Seems simple, right? Add a bit more power, lose a bit of weight, tidy up the drag and bingo, right? The reality is very different. At these speeds, the additional performance needed to gain even 1mph is huge. The velocity of the vehicle and the forces acting on every element of it grow exponentially as the speed increases. Take the wheels, for instance: the rotational force on them creates a gyroscopic effect that could overload the regular steering system (configured for 418km/h) to such an extent that if you turn, you may end up unable to straighten again.

11. 84

The years to the very day that Malcolm Campbell became the first man to drive a car over 482km/h, averaging 484.95kph thanks to a 2,300bhp 36.7-litre supercharged Rolls-Royce V12. How things have changed.

STORY Rowan Horncastle

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