zgred wrote:![Image](http://motorsport.nextgen-auto.com/gallery/pictures/2011/f1/gp-australia-25mar/528_medium.jpg)
So the way I see it is that the exhaust must be encountering the lower wheel hub element, otherwise it wouldn't be made of this white material. I should imagine this provides some benefits by adding to the low pressure suction zones in a similar manner to the beam wing.
What intrigues me is the temp paint on the bottom of the diffuser. I'm not 100% sure I agree with shelly who said that this was because exhaust gas was drawn in around the sides.
I am wondering whether the exhaust blowing over the top is heating the underside of the diffuser which will help with boundary layer excitement? Possible? Might explain the white material if it allows a bit more conduction.