Posted 07 December 2011 - 16:05
Two possible reasons
Firstly, the regulations changed to limit car overall width and it may be that narrowing the pod width to match the narrower tyre width was the best thing for aero. That would require the pods to get higher to keep up the total radiator area.
Secondly ,The growing use of CFD may have let the designers ( or aero men anyway) to be more adventuruos with sidepod shape. Historically anything with a curve or camber down on the car upper body was viewed with suspicion as it could induce lift . With CFD it is possible to model or visualize much more complex shapes so higher pod heights and downward sloping bodywork to get space under the wing , as in today's cars, is more feasible.
Something similar happened between the F-117 stealth fighter and the B-2 stealth bomber. The strange multi angled facets on the F-117 were not what the designers wanted for aero performance , it was just that ( apparently) the computer modelling of the day coudn't resolve too many angles for optimum stealth so flat surfaces were used. By the time the B-2 came along they had improved the modelling so it is much smoother shape ( i.e many, many facets) to help the aero performance.