RC F GT3 vs GT500. [Aero]

Despite their quite similar appearance FIA GT3 and Super GT GT500 are radically different. Without going into a high comparison, one is derived from a mass production car of  when the other is a prototype very cleverly disguised into a GT .

Photo par: オタク系男子

The RC F GT3 gets a 540ch V8 when his the GT500 hides under its hood a "modest" (much) over 500hp 4-cylinder. But the real difference lies in the design of both competitors and especially in their aerodynamics management.

Here the frame (commonly called tube) of a GT500:

This architecture (shared with DTM) enables more rigidity plus a light weight and a compact package but most importantly, to better manage the aerodynamic flow. Here's what looks like a GT500 bottom view. The following illustration shows a Toyota GT One but the principle is essentially the same (like all current proto sports ). The carbon tube is clearly visible here, the diffuser redirects the clean air flow above the flat bottom and around the tube. Sport proto and monoseaters cars try to get the largest volume of this air to the rear and mainly on the diffuser.

On Super GT, here's what it might look like (I do not know who is illustrator unfortunately).

This technique creates an extremely powerful ground effect and is responsible for the largest amount of downforce generated by a GT500. Indeed, if have compared the dimensions of the rear wings you will notice that the GT500 seems a lightweight compared to the GT3 one, yet the donwforce generated by the G500 is near the LMP one ! Obviously the rear diffuser plays an important role too. Finally here's a picture that can facilitate understanding the aerodynamic flow around each car.

On the GT3 and GT500, the air flow entering the engine bay is only used for engine cooling (heat exchangers, radiators) and supply engine air boxes. The heated air is directed to a low pressure area and significantly decreases drag generating some amount of downforce.

On the GT3 the airflow that passes under the car is routed directly to the rear diffuser when it is deflected on the flat bottom and around the tube on the GT500. The huge front canards on the GT500 create a low pressure area behind it (at the expense of a certain amount of drag) to improve the extraction of the airflow coming from the diffuser. Note that the little spoiler on the GT500 trunk helps to increase downforce on the FRONT axle.

German DTM cousins are very close in terms of aero GT500 but slow to adopt the 4-cylinder turbo engine, I can't wait to see them battling on the same track !