Bugatti, Koenigsegg and Hennessey have been locked in a battle to crack the haloed 300mph club for a production car and Bugatti has finally done just that with an a mind-boggling 304.77mph (490.5kph) run at parent company Volkswagen’s Ehra-Lessien high-speed facility in Germany.

However, that effort isn’t going to count for anything other than bragging rights at the local kopitiam because the Bugatti Chiron that made the run is too extensively modified from its original production form.

Top Gear broke the news in an exclusive as it was on the scene on 2 August 2019 to see test driver Andy Wallace hit the magic mark. Although the speed itself was TUV (Germany’s Technical Inspection Association) certified, it won’t count as a new production car speed record.

Many have wondered if the Chiron had the chops to make the record with its electronically limited top speed of 420kph (261mph) removed. Currently, as it stands, the Koenigsegg Agera RS retains its fastest production car title with its 284.55mph (457.94kph) run but no doubt it’ll want to crack 300mph now.

So, what exactly has been done to this menacing-looking Chiron? It’s no slouch in stock form but trying to crack the 300mph barrier is no joke either. For starters, the stock quad-turbocharged W16 engine putting out 1,479hp has been given a minor bump in performance though the transmission was stock.

Chassis manufacturer Dallara was called upon for the aerodynamics mods. It ditched the rear wing and air brake for a static unit for more downforce. The rear end has been elongated slightly as well and the exhaust was extended out to not disrupt the airflow of the car. Inside, the passenger seat and bits of the interior were tossed out to cut weight and a roll-cage was fitted.

One of the major hurdles in cracking the 300mph mark was always the tyres. Michelin stepped up with a custom set of Pilot Cup 2 rubbers that could change the number of entrants in the road-going 300mph club.

“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. 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,” explained Wallace.

Regardless that it isn’t a production car record, it’s still a remarkable engineering feat. Just an interesting bit of info, at the speed the Chiron achieved, it would have been covering 136 metres every second. Nonetheless, even more mind-blowing is the fact that a highly-modified 2006 Ford GT hit 300mph in the standing mile earlier this year. The Chiron took quite a bit more tarmac than that.

Odds are Koenigsegg might try to snatch the record back with its new Jesko hypercar and probably won’t modify it too much to ensure it tops its own production car record.