According to a report from Germany’s Auto Motor und Sport, the Woking based team’s rear diffuser design has been closely investigated by the FIA and the verdict is not very favorable for McLaren: they need to scrap the rear diffuser by the upcoming race in Australia, while allowed to use it in Bahrain.
“McLaren aerodynamically exploited the hole for the external engine starter, making it much bigger than necessary and thereby gaining another diffuser level,” said the aforementioned report, as showed by the GMM news agency.
What’s interesting is that, although the device is now considered illegal by the ruling body, the team is allowed to use it in Bahrain. Until the time when this article was written, the controversial rear diffuser seems to hardly make a difference, as Hamilton and Button ended the qualifying session on Saturday in 4th and 8th respectively.
Nevertheless, this is the 3rd controversial car part found on the MP4-25 during the past week, following the already famous design of the rear wing and the air inlet on the upper side of the bodywork – that can influence air flow around the car in straight line and be activated by the driver with his knee, via a device from within the cockpit.
As far as these two aerodynamic features are concerned, it seems the FIA has already agreed they were as legal as sunshine, with the governing body’s delegate Charlie Whiting considering it a “simple but brilliant trick.”
Soon after that, some of the teams in the paddock – Red Bull mainly – admitted they will look into the design and try to copy it as soon as possible, while others – Renault in particular – have hinted that they may protest the FIA decision in due time.