How I can find out the center of pressure??

I believe you'll need to create a variable (using the Calculate tool) for pressure * X, then use the integration tool to integrate that quantity on the surface in question.  (The expression would be 

pressure * coords[:,0]

 Then also Integrate the pressure on the surface in question.

Center of Pressure (in X) = Integral ( pressure * X ) / Integral ( pressure )

then similar for other dimensions, Y and Z.

I believe you'll need to create a variable (using the Calculate tool) for pressure * X, then use the integration tool to integrate that quantity on the surface in question.  (The expression would be 

pressure * coords[:,0]

 Then also Integrate the pressure on the surface in question.

Center of Pressure (in X) = Integral ( pressure * X ) / Integral ( pressure )

then similar for other dimensions, Y and Z.

Hi! First of all, thanks you ver much to help me!
Following your steps I have done this:

and then, I use Integration to the car surface

And now I have to divide, right? but divide Average or Sum?

Thanks for all!!

Javi

Hi! First of all, thanks you ver much to help me!
Following your steps I have done this:

and then, I use Integration to the car surface

And now I have to divide, right? but divide Average or Sum?

Thanks for all!!

Javi

The sum and average are different by the factor of the area.  So whether you use the Sum column or the Average column, the result will be the same.

Video might help