2003-2004 Lister Storm LMP

Images copyright and courtesy Bob Chapman @ Autosport Image and Paolo Gervasio
Text copyright Michael J. Fuller

Looking up into the front diffuser.  The exit is quite free of obstructions.
The intake in front of the rear wheel is utilized to cool the rear brakes.  The duct ends at the rear wheel and does not continue through the rear of the car.  Note the gurney lip on the exit of the front underbody.  This gurney creates a low pressure area that encourages the diffuser air to exit out the side of the car.
Of interest in this shot is the duct that begins at the rear wheel and exits out the rear of the car either side of the rear diffuser.  Interacting with the engine exhaust which is directed into this duct, the idea is to use the low pressure suction created by the engine exhaust's high speed flow to suction off the high pressure created by the spinning rear wheel as well as siphoning off the engine bay's flow through from the coolers.
Looking into the exit from the rear we can see where the exhaust pokes into the duct enhancing the low pressure and encouraging the air flow from the engine bay to exit out the rear of the car.  Andy Thorby, "This works quite well at sucking the air out of the engine bay, mainly, of course, the air that  has passed through the radiators."

©Copyright 2004, Michael J. Fuller