Ferrari F2005 - revised diffuser 08 May 2005
For Spain the side walls of the diffuser have been extended, with vertical ends instead of sloped one (see yellow line). This allows for an additional profile (see red arrow) that creates a sort of double channel (one above the other). This provides more efficient air extraction from beneath the car, increasing the speed of airflow on exit. This generates additional downforce and should provide more rear-end stability.
