Finding a solid car for Ansys Fluent

Hi everyone,

I'm doing my final degree project about aerodynamic car simulations with Ansys Fluent.

I need a solid CAD to introduce it into the program. I downloaded several cars from Internet but all of them have the same problem: they are made of surfaces. The problem is that when I try to sew these surfaces together problems appear always.

With one of the CAD which I downloaded, I finally obtained a single surface. But there is a piece of this surface that stays inside the car... that makes me impossible converting it into a solid.

I don't know what to do... Could somebody help me? I attach the last version of my car.

Thank you very much for your cooperation in advance.

SolidworksEducator Student