In normal operation, the Bugatti Chiron is limited to 236 mph. If you want to head for its electronically-limited 261-mph max, you'll need to activate Top Speed mode by inserting a second key into a slot between the driver's seat and the door sill. But it's not as simple as twisting the key and taking off.
As Le Mans-winner and Bugatti test driver Andy Wallace explains in this Carfection video, the Chiron can actually shut you out off Top Speed mode—if the car doesn't find conditions safe enough for a 261-mph run.
"You put [the key] in and twist it, and what you're doing is asking the car to go into Top Speed mode," Wallace says. "It will then go through a system of checking, making sure it's happy that everything's as it should be. It even checks the age of the tires."
If everything is safe, the Chiron goes into low-drag position, with ride height and the rear wing lowered, and front-axle downforce reduced via the repositioning of two hydraulically-actuated flaps ahead of the front wheels. Then you're good to go, so long as you're pointed in a straight line.
Wallace explains that if you apply more than 90 degrees of steering angle, or if stability control or ABS is activated, Top Speed mode immediately disengages, limiting you to 236 mph. You can restart Top Speed mode by twisting the key again, but the parameters for automatic deactivation stay the same.
As Carfection's Henry Catchpole points out, these parameters might cause issues at VW's Ehra-Lessien test track, where the Bugatti Veyron Super Sport hit its 268-mph top speed in 2010, setting a production-car top-speed record. In order for the Veyron to hit its top speed there, it had to before flooring the throttle at the straight in search of 250 mph and beyond.
So how could you do the same in the Chiron without deactivating Top Speed mode? You can't, apparently, but Wallace says it's not an issue.
"With the Chiron, you can come off the banking, stop the car to zero, go, reach [top speed], and still stop before you get to the other end of the banking," Wallace says. "It's staggering how much faster this car is," he added.
Talk of Top Speed mode begins around 12 minutes into this Carfection video, but the whole thing is worth watching for a look at the fascinating engineering of the Chiron. Wallace even finds time to draw a comparison between the Chiro, and another car he famously maxed out at Ehra-Lessien, the McLaren F1. Guess which one he thinks was scarier?
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