What is the Bugatti Chiron? Is it just a Veyron in drag? Not quite. It's a luxurious road car that can also outrun the fastest LMP1 prototype at Le Mans, with a top speed limited to 261 mph. . . for now. And while it might be an evolution of the VW Group's first world beater, the Chiron is also more of a drivers' car since it has a chassis set up to oversteer and will only be available as a coupe. With 1479 horsepower and 1180 lb.-ft. of torque on tap, there's no room for any open top nonsense.
People started to buy them at around $2.6 million a pop even before anybody outside VW could go for a drive. It's important to note that the average Bugatti customer has 42 cars. Interestingly enough, Bugatti will only find out next year exactly how much faster they can go with the Chiron than with their 267.8 mph Veyron Super Sport in 2010. The only place to test the Chiron in relative safety with its limiter removed remains Volkswagen's Ehra-Lessien test track north of Wolfsburg.
Bugatti's former Head of Technical Development Willi Netuschil retired in December after the first production Chirons hit the road, but not before I could ask him a whole lot of questions regarding his legacy project and the future of Bugatti. He told me this before we could get into glowing brake rotors and fuel consumption with the Top Speed mode key in place:
Our overriding goal is to reach maximum performance and top speed. To accomplish this we will do everything that is appropriate. If we cannot achieve our future performance goals by using traditional means, alternative technologies will be an option. Then we will make careful choices that will make our customers happy. They regard a Bugatti as an investment and collectors' item to be passed on to the next generation in their family. A car's value only increases over time if the car remains in a drivable condition. That is why it is important to develop technologies that stay operational in the future.
With that in mind, let's dig deep into how Bugatti makes a 261 mph car as reliable as your aunt's Golf.
The Chiron has spent more than 300 hours in the wind tunnel. The modern design process requires intensive aero-simulations and computational work. The full scale model goes to the wind tunnel to ratify those decisions made in the virtual world. The wind tunnel testing helps to optimize invisible areas in terms of air flow and underbody construction.
It's a largely enclosed vehicle with a powertrain that generates twice as much heat energy as kinetic. To reduce drag, components like the air curtain, the front splitter and all the intakes were designed to guide the air through and around the car, keeping the turbulence created by the rotating wheels to a minimum. The retractable rear spoiler can adopt four positions depending on the driving mode and your speed, aided by the adaptive chassis which allows different ride heights to maximize performance.
The car's drag coefficient is 0.38 in EB (standard) mode, 0.40 in Handling, 0.35 in Top Speed and 0.59 when the air brake is active.
The process may start with the first design sketches, but somewhere between the 1:1 clay models and the more than 30 actual test vehicles Bugatti built, there's Dallara's driving simulator.[contentlinks align='left' textonly='false' numbered='false' headline='Related%20Story' customtitles='Bugatti%20Designer%20Sasha%20Selipanov%20Lands%20at%20Genesis' customimages='' content='article.31868']
With this, the Chiron's parameters could be changed on the fly, with Bugatti gaining valuable data free of noise in the signal and errors during tool calibration, something that can be an issue with a real car on the track. The simulation was followed by the physical tests of the components on various rigs, all moving towards the construction of functioning Chiron prototypes which then could hit the proving grounds.
The Chiron's powertrain weighs approximately 1388 lbs. The engine itself is almost 970 lbs, despite having its intake tube, the charge air system and the chain housing all made of carbon fiber. It also features a lighter crankshaft and more titanium components than the Veyron, but the 25 percent power boost is mostly thanks to bigger turbochargers, improved intercoolers and the duplex fuel injection system with its 32 injectors.
Bugatti's seven-speed dual-clutch gearbox is made by Ricardo. In order for it to handle 1180 ft.-lb. of torque, they developed a special gear oil, strengthened the gear teeth, and fitted it with the largest and strongest clutch ever used on a passenger car.
Bugatti had to redesign its engine test bench for the Chiron as the existing one couldn't handle the loads. The W16 now employs two-stage turbocharging, meaning that the Chiron moves off the line with only two turbochargers in operation. The other two are only activated at about 3,800 rpm to ensure a linear power delivery. Does that make the Chiron more fuel efficient as well? Maybe, but forget about that in Top Speed mode.
Theoretically, if you were able to go full speed until the 26.4 gallon (100 liter) tank hits empty, Bugatti believes the trip would take about nine minutes. Nine!
Bugatti admits that the most crucial development issue was finding solutions for the heat management and dissipation.
The Chiron is equipped with two cooling water loops. The primary is the high-temperature loop for engine cooling, while the secondary is a low-temperature one for charge air cooling. The high-temperature loop features one main and two auxiliary radiators with 37 liters of cooling water that is pumped through the entire cooling loop in about three seconds. The low-temperature loop is equipped with one radiator filled up with 12 liters of water. This loop prevents the charge air from overheating in stop-and-go traffic.
With the three coolers for the engine oil, gearbox oil and rear axle differential oil, the two water/air heat exchangers and the hydraulic oil cooler, the Chiron's cooling system consists of a total of ten radiators.
The hot gases leave the car through a titanium exhaust system ending in six tailpipes, with four routed to the rear and two pointing downwards. The system is equipped with four pre-converters and two main catalytic converters. The total active surface of the six converters is about 230,266 m², otherwise known as more than 30 soccer fields.
Bugatti uses carbon ceramic brake discs made from carbon silicon carbide (CSiC). The front and rear brake discs of the Chiron are 20 mm larger and 2 mm thicker than the Veyron's. The brake calipers are forged from aluminum and then milled into an asymmetrical design to dissipate all the heat effectively. The front-axle brake calipers are each fitted with eight titanium pistons, with six titanium pistons on each caliper of the rear axle. Interestingly, the pistons' diameter varies on each caliper to ensure even distribution of pressure over the entire surface of the brake pad.
Bugatti says the brakes will survive a full stop from 262mph, although they have no idea about the braking distance yet. All they know is that from 186 mph, it's 902 feet (275 m).
Michelin knows how to put a tire on an Airbus A380, so when Bugatti asked them for even more performance, they just put their prototypes on their aerospace rigs. Their mission was to make them transfer a maximum torque of up to 3687 ft.-lb. per wheel safely to the road.
The Chiron's rubber has a 14 percent and 12 percent larger surface front and rear, with the sizes being 285 / 30 R20 at the front and 355 / 25 R21 at the rear. Further great news for Chiron buyers is that Bugatti switched from PAX technology with a special mounting process to regular tires with a standardized process. This not only reduced the weight of the car, but also the service bills, something the owner of a Chiron would definitely be worried about.
To reach the desired levels in comfort, handling and top speed combined with a regular tire mounting technology, Michelin and Bugatti had to go through more than 200 sets of tires during development.
The Chiron has a double-wishbone suspension with electronically controlled shock absorbers that can raise or drop the ride height as well as the compression in five stages. In the standard setting, the Chiron stands just 47.7 inches tall.
A carbon fiber monocoque is the key to a light and rigid chassis. Bugatti's was engineered with Dallara, who are now also manufacturing it using a sandwich procedure. The production of a monocoque takes four weeks. With this, the Chiron reaches a torsional rigidity of 50,000 Nm per degree and a flexural rigidity of about 0.25 mm per tonne.
Bugatti also says that if all the fibers used in the monocoque were laid out end to end, they would stretch nine times the distance between the earth and the moon.
What isn't made of titanium, magnesium or aluminum on the Chiron has to be carbon fiber in order to keep its dry weight at 4398 pounds. For the first time, the rear end of the car is also made from carbon fiber, saving 17.6 lbs. right where it matters the most.
The main actuators used for switching between the individual driving modes are the electronically controlled power assisted steering, the electronically controlled shock absorbers, the four-wheel drive with the "easy to drift" feature, the chassis height adjustment, the electronically controlled rear differential, the aerodynamic control system, the Traction Control System, the stability and brake control system (ESC) and the Tyre Pressure Management System.
When a speed of 50 kph is reached, the vehicle automatically switches to the base "EB" mode for comfortable everyday use. There's also "Lift" for when you need maximum clearance.
While the windows roll up automatically at 92mph, if the Chiron is driven faster than 110 mph, the car also switches to "Autobahn" mode. In this case, the chassis is lowered and the steering and shock absorber settings are automatically adjusted for stable handling at higher speeds on the highway. The kinetics and aerodynamic downforce are improved for maximum stability.
In the "Handling" mode, all systems are set for maximum agility, performance and controlled drift moments. The latter function is thanks to the permanent all-wheel drive's electronically controlled rear axle diff lock and the traction control allowing more oversteer, controlled by the ESC.
In short, the handling mode is the "Autobahn" mode quicker steering and firmer damper characteristics. You can achieve a lateral acceleration of 1.5 g, while the speed is limited to 236 mph.
Top Speed Mode
There's a separate key to activate Top Speed mode. Oh yes.
For those "I wanna go fast" moments, the Chiron does not switch off climate control or any other systems. The driver only gets to see information on the displays that are relevant, navigation or infotainment will fade out. The steering and dampers are adjusted to maximum stability, the chassis height and aerodynamics to maximum speed and that's it. Next stop is at 262 mph, or more if you're a Bugatti test driver. Remember: you only have nine minutes worth of gas. Maybe less.
At this point, Bugatti only knows that the Chiron will reach its top speed faster than the 1200 horsepower Veyron SS got to 267.8 mph. The Chiron's 0-186 mph sprint takes just 13.6 seconds.
Half a million kilometers
Bugatti put more than 310,000 miles into its prototypes to make sure the 500 Chirons they make will be worthy of the badge. Despite battling with the heat, Mr. Netuschil says there was no part that actually broke or burst during their final functional and endurance tests.
He also told me the traction control can be switched off completely without making the Chiron undriveable, but if you go there, "you should be an excellent driver."