The coolest car at Renault’s booth at the Geneva Motor Show was the Red Bull RB7, the Renault-powered Formula One car which won the 2011 championship in the hands of Sebastian Vettel. Unlike the old or partially complete F1 cars displayed at many carmakers’ booths, this was the real deal, as evidenced by this flattened oval exhaust pipe which played a key part in the car’s dominance.
What the exhaust did was direct hot gas over the diffuser, the aerodynamic structure in the rear of the car which creates downforce. Such exhaust-blown diffusers had been around since the late 1990s, but it was in the 2010 season that they became crucial to aerodynamic development with Red Bull’s RB6, the car which gave the team their first championship. Designer Adrian Newey kept the design for 2011’s RB7, a much more dominant evolution of the RB6, whose exhaust-blown diffuser was analysed on technical illustrator Craig Scarborough’s blog.
Over the past two years, exhaust-blown diffuser development continued at a furious pace, with engines programmed to feed hot air to them even while the drivers were off the throttle. This practice is what gave cars like the RB7 their peculiar off-throttle sound, which you can hear in this video, taken at the 2011 Italian Grand Prix.
A few months ago, tough men in sunglasses would have prevented me from taking a photo of the car’s rear, but as exhaust-blown diffusers were outlawed for 2012, this car is now ancient history. Gracing Renault’s booth as their most powerful hybrid, it was painted to look like Sebastian Vettel’s Kinky Kylie, but a tiny sticker on the rear wing gave it away as Mark Webber’s car, the winner of last year’s ultimate Grand Prix in Brazil.