Bugatti rips up the rule book and resets the bar with reworked Chiron. Blink, and you will miss it...
Callum Alexander | Callum on Cars | News
Bugatti are fabled for defying convention with the 267mph Veyron Super Sport. Now, history has repeated itself with the Chiron Super Sport 300+: Andy Wallace drove at 304.77mph on 2 August 2019 at Volkswagen’s Ehra-Lessien test track. It means that it has become the first hypercar to break the 300mph barrier - the clue was in the name.
Rubber stamped by Germany’s TUV - Technical Inspection Association - Bugatti’s juggernaut climbs to the top of the outright speed tree. It passes a selection of predecessors previously possessing the fastest car in the world title from; SSC’s 256mph two-way average in 2007; Hennessey’s 270mph two-way average in 2013 as well as Koenigsegg’s 284mph vmax effort in 2017.
But Bugatti has toppled all the challengers in bursting the 300mph bubble first. It transpires that the ambition has been the target for the past six months, with a team of Bugatti, Michelin and Dallara engineers plotting to build a car to pass 300mph. It’s a case of mission accomplished.
A raft of upgrades has been drafted onto the ‘standard’ Chiron to enable this accolade. These modified components updated the powertrain and chassis configurations, creating the Hypercar missile that is the Chiron Super Sport 300+.
First, Bugatti increased the power output of the 8.0 litre W16 engine from 1479bhp in the standard Chiron to 1578bhp in the Super Sport 300+, just to be sure it had enough to tick past the 300mph mark.
Bugatti then stripped the Chiron of any weight that was surplus to requirements in pursuit of their target - so the passenger seat was removed as well as the rear wing. Although that passenger seat will be reinstalled for production examples. Also, harnessing the airflow became a critical aspect: the Super Sport 300+ has morphed into a Longtail-esque version - it is 25cm longer than the original Chiron - this reduces drag and increases aerodynamic efficiency.
The Bugatti boffins battled to balance the delicate pendulum of least drag against optimum cooling efficiency. For the Super Sport 300+ Chiron to breach 300mph, it has to drive through the air with as little resistance as possible, whilst ensuring sufficient surface area to consume enough air to feed the powertrain and keep it cool.
Chief among the aero amendments is the quad tailpipes protruding from the rear diffuser in place of the central exhaust on the normal Chiron. Split into a double duo on either side, they have a purpose: to dispel exhaust gases away from the rear diffuser, so as not to interfere in the aerodynamics. They also add a severely cool focal point to the Chiron’s menacing look.
The aspect that demanded the most extensive modifications though was the tyres. The Michelin Pilot Sport Cup tyres used on the standard Chiron were reinforced, with the belts inside adapted to withstand the 4,100 times tyre rotations every minute at 300mph. These bespoke tyres were tested up to 318mph, as well as x-rayed to be sure they were suitable for the challenge.
The biggest hurdle Michelin had to overcome was not the velocity imposed on the tyres but the heat build-up that they would be subjected to: the stipulations Michelin had to incorporate in the design was a strong, balanced tyre that enabled adequate heat dissipation.
The increase of friction as a result of the incrementing speed causes the tyres to endure temperatures that could result in failure. To combat this, Bugatti have developed a system called Laser-Guided Ride Height; it’s a system that interprets the road ahead and adapts the suspension to contend with the tarmac surface. These technological provisions provide a net of reassurance to drive Andy Wallace as the Chiron ventured into the unexplored realm of 300mph.
It is an exceptional achievement but one that might be a bit bittersweet, as the 304.77mph clocked by the Chiron Super Sport 300+ is not an official production car record. To set a record, Bugatti to follow the record speed attempt protocol by recording a speed in one direction, then replicate that in the opposite direction. An average speed is then taken from the two figures to qualify for the official accolade. But Bugatti only recorded the top speed in one direction.
There is a subtle and overlooked reason that prevented the Chiron from claiming the title - it added a fundamental complication. The Ehra-Lessien test track was built decades ago and has only been driven around in the clockwise direction. Subsequently, the tarmac grain has been moulded in that direction; if Bugatti turned the Chiron Super Sports 300+ around, it would have to drive against the grain. This abrasive contact with the tyres could potentially strip tread off the tyres quickly, which was a risk Volkswagen weren’t prepared to take, and so decided against it.
It’s a shame that Bugatti won’t be officially listed as having topped 300mph first, but unofficially, the car universe will know they did.
The only slight snags are that it will cost £4.2million pounds, and only 30 examples will be made.
Callum Alexander | Callum on Cars | News
Photos: Bugatti
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