Hi Alejandro - great to see young people using simulation for their school projects! 
Let us dissect each project and I will give you some tips on where you should work on.
- For the frontwing I can definitely tell you that the mesh is too coarse and you should increase the fineness of the mesh and make sure that the boundary conditions are set correctly.
Use this tutorial for your wing: Front Wing - CFD Analysis
- For the car itself the domain is way too small and the boundary conditions to not match as well. Also make sure that you use velocity inlet and pressure outlet and not the same type like velocity - velocity and pressure - pressure which has numerical reasons.
Please have a look at the following project and use it as a template: Full Car Aerodynamics
Let me know if you have any further questions. If so, please either tag me or one of our PowerUsers @Get_Barried, @vgon_alves or @pfernandez.
Best,
Jousef