The W16 of Bugatti: a look back at the history of a one-of-a-kind engine

Today, in the middle of the electrification era, you need far more than the fingers of both hands to count the sports cars that easily exceed 1,000 CV of power. But in 2005, when Bugatti unveiled the figures for its Veyron 16.4, everything sounded different. No less than 16 cylinders in an unprecedented configuration, eight litres of displacement, four turbochargers, and 1,001 CV of power… The compact W16 allowed the Veyron 16.4 to accelerate from 0 to 100 km/h in 2.5 seconds and exceed 400 km/h of top speed.

Just over ten years later, in March 2016, the Italian brand presented the successor to the Veyron, the Bugatti Chiron. Under the bonnet, the evolution of the W16 raised output to no less than 1,500 CV and a maximum torque of 1,600 Nm. This is the story of the W16, a one-of-a-kind engine, to which can be credited the creation of the category of true “hypercars”.

The origins: 18 cylinders that were reduced to 16

No bigger than a V12, weighing around 400 kg… and producing 1,000 CV of power. At the time, not even Bugatti’s own engineers believed it was possible to make the idea real that Ferdinand Karl Piëch, then head of Volkswagen AG, presented to Karl-Heinz Neumann, head of engine development.

Piëch’s initial idea of an 18-cylinder engine quickly gave way to a focus on the W16, the result of placing two V8 blocks side by side at an angle of 90 degrees. It should be borne in mind that the first sketches date from the late 1990s. There were no production cars with engines of more than 12 cylinders… nor any capable of exceeding 350 km/h.

Already in the first tests, carried out in 2001, the W16, which consisted of more than 3,500 parts and was assembled entirely by hand, reached 1,001 CV on the test bench. But the goal was still far from achieved. All the challenges associated with fitting this engine in a car intended for road use remained to be solved: cooling, ventilation, routing of exhaust gases…

Part of the solution was an exhaust system made entirely of titanium. But the truly innovative element was its cooling system, with two circuits circulating up to 40 litres of coolant, requiring three heat exchangers at the front of the vehicle to keep the engine at its optimal temperature. A separate circuit reduced the temperature of the charge air coming from the four turbochargers by up to 130 degrees Celsius, thanks to two additional intercoolers inside the engine bay.

Speed record: the 431.072 km/h of the Bugatti Super Sport

The W16 had plenty of potential to keep evolving, even if only “by turbo”. With larger turbochargers, among other modifications, from 2010 it was delivering 1,200 CV in the Veyron 16.4 Super Sport, which that same year entered the Guinness World Records by setting a top speed of 431.072 km/h, a record for a production car.

The Bugatti Veyron 16.4 Super Sport was followed by the Grand Sport and Grand Sport Vitesse versions, which had owners even before they were announced and are now considered genuine collector’s items. Until the successor to the Veyron arrived: the Bugatti Chiron. And Bugatti had one thing clear: the engine had to remain a W16.

Bugatti Chiron: the magic of forced induction

More powerful, more efficient, just as compact… The W16 formula remained valid, although the engine was practically redeveloped from scratch while staying faithful to forced induction. The result was a 50% increase in power over the original W16, reaching 1,500 CV… and 100 CV more, to reach 1,600 CV, in the Chiron Super Sport and Chiron Centodieci. Again, something never seen before.

The secret? The new sequential turbocharging, with two turbochargers per eight-cylinder bank working in two stages, and almost 70% larger than those of the Veyron. Of course, it was not the only important change. For example, each cylinder now had two injectors (32 in total).

With this new engine, and thanks in large part to an active aerodynamics system, the Chiron Super Sport 300+ became in 2019 the first production car to break an record that was unthinkable only a few years earlier: exceeding 300 mph, recording a top speed of 490.484 km/h, equivalent to 304.773 mph.

Each of the engines fitted to the 500 units of the Chiron that will ultimately be built is made at Volkswagen’s engine plant in Salzgitter, where two expert technicians hand-assemble over six days the 3,712 parts that, according to Bugatti, make up this unique piece of engineering.

https://www.youtube.com/watch?v=gwrQ3cXttio