Updated: May 14, 2021
With the new Bugatti Chiron Super Sport 300+ creating waves in the automotive world recently - i found it interesting to analyse and understand the aerodynamic differences between the standard Chiron and the 300mph version. Here’s what i see.
Let’s detail the visible changes - 250mm body extension at the rear, removal of wing, lower ride height, modified front splitter, modified rear diffuser.
The upper surfaces of a car body such as the Chiron inherently produce lift; so it's important to direct efforts at counteracting or neutralising the net lift with other aerodynamic changes. As this is a high speed run, It's logical that Bugatti made these modifications with the main intention of minimising drag and providing an aerodynamically stable platform.
This philosophy will be the main focus of the changes listed above. I’m reading a figure of 2000kg of positive lift was expected from this platform at 300+mph, so there would have been quite a lot of work to do there.
The most aerodynamically efficient method of neutralising this positive lift is to improve performance of the underfloor - The modified front splitter would assist in maximising the mass flow and quality of air travelling underneath the car, while the extended and more aggressive diffuser permitted by the rear extension (and repositioning of exhaust exits) would ensure this air leaves the underfloor efficiently, whilst possibly bringing the CoP rearwards to closer match the CoG through leverage.
The lower ride height would also help the car to capitalise on these changes by maximising the airspeed (therefore minimising the pressure) of this underfloor airflow. The reprofiling of the rear would also assist in reducing the low pressure area behind the car and further reduce drag.
So, less of the high drag wings, dive planes and other flow modifiers you see in lower speed motorsport and more emphasis on low drag features like underfloor features.
Love it. Congratulations Bugatti :-)