Why doesnt a car fly off from the road after attaining a certain speed?

I was wondering why cars don‘t work like airfoils due to their shape. I‘m talking a flat bottom with a curvy top. Sure not your ideal Epler airfoil but why is it that an airplane doesn‘t suddenly shoot up from the road? Is it the density of the car. Also cars usually want downwards force (inverted lift) for more traction right so I suppose that could be a reason.

They produce way too much drag to lift off the ground - although some lift may be produced due to their shape and movement it is nowhere near enough to lift them up. Although, sports cars and especially formula one cars are a different matter - they are incredibly streamlined to make them go quicker and parts of their design use the same aerodynamic principles as airplane aerofoils do. They have to have certain weights to prevent them lifting off the ground. If you look at some sports cars they have a sort of 'handle bar' at the back and this is to help keep their traction and prevent them from lifting off and therefore loosing control.

There is some lift generated at very high speeds, true. And at speeds exceeding 100 MPH, the designer has to take that into account in the design of the car. However, for production consumer autos, that is not a problem, speeds are too low. And you don't always want increased traction as that increases friction. Ideally you want traction to stay constant. Unless you have a race car.

Basic physics is the reason why. First, the automobile has more mass, and is not streamlined like an aircraft. Hence, no lift. Secondly, a car would have to go much faster to attain any chance of lifting off.

is the car has been crash or front end damages before?

You let the cat out of the bag when you said: I changed the motor, transmission mounts and half-shafts! CV axles never break, there's nothing to wear-out. A solid piece of steel axle shafting does not break . The half-shafts aren't the correct part number or your buying crappy box store parts. It isn't possible for a rip roaring 115 horsepower engine to break an axle shaft.

is the car has been crash or front end damages before?

You let the cat out of the bag when you said: I changed the motor, transmission mounts and half-shafts! CV axles never break, there's nothing to wear-out. A solid piece of steel axle shafting does not break . The half-shafts aren't the correct part number or your buying crappy box store parts. It isn't possible for a rip roaring 115 horsepower engine to break an axle shaft.

They produce way too much drag to lift off the ground - although some lift may be produced due to their shape and movement it is nowhere near enough to lift them up. Although, sports cars and especially formula one cars are a different matter - they are incredibly streamlined to make them go quicker and parts of their design use the same aerodynamic principles as airplane aerofoils do. They have to have certain weights to prevent them lifting off the ground. If you look at some sports cars they have a sort of 'handle bar' at the back and this is to help keep their traction and prevent them from lifting off and therefore loosing control.

There is some lift generated at very high speeds, true. And at speeds exceeding 100 MPH, the designer has to take that into account in the design of the car. However, for production consumer autos, that is not a problem, speeds are too low. And you don't always want increased traction as that increases friction. Ideally you want traction to stay constant. Unless you have a race car.

Basic physics is the reason why. First, the automobile has more mass, and is not streamlined like an aircraft. Hence, no lift. Secondly, a car would have to go much faster to attain any chance of lifting off.