Cover Open wheels
Open wheels create a great deal of drag and air flow turbulence, similar to the diagram of the mirror in the “Turbulence” section above. Full covering bodywork is probably the best solution, if legal by regulations, but if partial bodywork is permitted, placing a converging fairing behind the wheel provides maximum benefit.
Minimize Frontal Area
The smaller the hole your car punches through the air, the better it will accelerate, the higher the top speed, and the lower the fuel consumption it will have. It is usually much easier to reduce FA (frontal area) than the Cd (Drag coefficient).
Converge Bodywork Slowly
Bodywork which quickly converges or is simply truncated, forces the air flow into turbulence, and generates a great deal of drag. As mentioned above, it also can affect aerodynamic devices and bodywork further behind on the vehicle body.
Spoilers are widely used on sedan type cars such as NASCAR stock cars. These aerodynamic aids produce downforce by creating a “dam” at the rear lip of the trunk, raising the air pressure over the trunk. Where a notch left by the rear window exists a spoiler can help restore pressure to the void behind the window.
Wings are the inverted version of what you find on aircraft. They work very efficiently, and in less aggressive forms generate more downforce than drag, so they are loved in many racing circles and by high performance road car builders. Wings are best placed in areas that have clear airflow to them. Placing a wing behind an obstruction reduces the downforce the wing can produce.
Use Front Air Dams
Air dams at the front of the car restrict the flow of air reaching the underside of the car. This creates a lower pressure area under the car, effectively providing downforce. In many cases, the air dam also reduces the Cd of the vehicle.
Use Aerodynamics to Assist Vehicle Operation
Using vehicle bodywork to direct airflow into openings, for instance, permits more efficient, smaller openings that reduce drag penalties. Quite often, with some forethought, you can gain an advantage over a competitor by these small dual purpose techniques.
Another useful technique is to use the natural high and low pressure areas created by the bodywork to perform functions. For instance, Mercedes, back in the 1950s placed radiator outlets in the low pressure zone behind the driver. The air inlet pressure which fed the radiator became less critical, as the low pressure outlet area literally sucked air through the radiator.
A useful high pressure area is in front of the car, and to make full use of this area, the nose of the car is often slanted downward. This allows the higher air pressure to push down on the nose of the car, increasing grip. It also has the advantage of permitting greater driver visibility.
Keep Protrusions Away From The Bodywork
The smooth airflow achieved by proper bodywork design can be destroyed quite easily if a protrusion such as a mirror is too close to it. While it is important to design an aerodynamic mount for a mirror, the mirror itself needs to be placed far enough away from the bodywork to avoid adverse affects.
Rake the chassis
The chassis, as mentioned in the aerodynamics theory section above, is capable of being slightly lower to the ground in the front than in the rear. The lower “Nose” of the car reduces the volume of air able to pass under the car, and the higher “Tail” of the car creates an expanding space where a vacuum effect can form. This lowers the air pressure beneath the car, creating downforce.
Cover or streamline Exposed Wishbones
Exposed wishbones (on open wheel cars) are often made from circular steel tube to save cost. However, these circular tubes generate turbulence. It may be worth considering the use of oval tubing, or a tube fairing that creates an oval shape over top of the round tubing.