2001-2005 Dallara LMP

Images copyright and courtesy Phil CK, Juha Kivekas, and Pat Michl
Text copyright Michael J. Fuller

Donnington debut 2001Note the end fence on the horizontal plate.  Also note the rather poor placement of the rear wing flap mounts, in the low pressure zone underneath the flap. 
Donnington debut 2001Pretty standard rear diffuser.  Here is how it looked at the Donnington round before Le Mans.  Full width, symmetrical strake location about centerline (yellow highlights).  The angle of attack of the diffuser seems steeper than the Audi R8.  The rear diffuser has become real estate for advertising. 
Le Mans 2001By Le Mans the Dallara's diffuser was narrower.  Note the inserts outboard and compare the distance gap between the outer most strake and the inner wall of the diffuser.  The main issue here is the narrowed diffuser is probably slightly more efficient as it has less interaction with the turbulence of the spinning rear wheels. 
Fontana Grand-Am 2002Shown here in Grand-Am specification at Fontana 2002.  A tail wide gurney has been added to compensate for the lack of diffuser (illegal in Grand-Am).  Also note the very large endplate, also to generate more rear grip.

©Copyright 2004, Michael J. Fuller