A&Q about 350Z
Q:
also one more thing, if the whole purpose of an airdam or windsplitter is to prevent air from going under the car, how come some race cars have like a notch in the middle-lower front bumper section? Isn't that like inviting the air to go under the car?
here's an example- The F50 GT
You see how the lower front bumper has like a notch in the middle of the bumper at the bottom?( by notch I mean the front splitter goes slightly up towards the middle of the bumper) Wouldn't that allow air to go under the car?
another example-the new Audi R10
the middle of the front splitter goes up, again wouldn't that allow air to go under the car?
A:
Airflow under a car isn't necessarily bad. Chin splitters aren't designed to prevent airflow under a car, but rather control how much, and in what manner the air flows underneath the car. If too much air flows underneath the front of the car, the nose can lift up. The reason that there's a "gap" in the middle of the chin splitters is partially to direct air away from the front tires, where there would be lots of drag and turbulence. You can't eliminate all of the air flowing underneath of a car, so the goal is to manage it as best as possible.
Of the air that does end up flowing under the car, it is often used to suck the rear end of the car to the ground. Many supercars and race cars use flat undertrays, or specifically sculpted underbodies which accelerate the air to create a lower pressure between the car and the road. The car acts as a forced narrowing in the airstream to create a venturi effect: the air flowing underneath of the car is allowed to expand once it passes the rear bumper, creating an area of low pressure. In the case of flat undertrays, the "rake angle" of the car is setup so that the nose is slightly lower than the tail, to achieve the same type of effect. This way the air tends to push the car down onto the road, rather than acting like a wedge tryint to pry the car off of the road.
A:
o, so basically you want to control the amount of air that goes under a car, and make it work for you
A:
You might also want to use the high pressure zone above the splitter to create some downforce by letting the pressure act on the area of the splitter.