There's more still to be learnt from the initial CFD analysis that we can look at before getting into the new aero design. Looking at the streamlines and static pressure distribution for example, reveals a lot about the behaviour of the airflow over the car and how we can make the most of it at the design planning stage. For instance, let's have a closer look at the front of the car.
My initial plan was to replace the existing fog lamps with the inlet ducts that will supply cold air to the front brake discs. Looking at the static pressure distribution around the front of the car however, this may not actually be the most efficient use of the airflow. Good airflow through a cooling duct relies on a pressure drop between the high pressure at the inlet and the low pressure at the outlet. This is why you'll see a properly designed F1 radiator duct for example, that has a diffuser inlet section to raise the static pressure ahead of the radiator core and a converging outlet duct section to accelerate the airflow and lower the static pressure behind it. Back to the front of the Z3 though, it's clear that the static pressure is much higher (red) in the main radiator inlet area than it is at the outer edges of the front bumper. Therefore, my best bet is to do something more like the BMW Motorsport touring cars, where they blank off the fog lamps and presumably supply the brakes with cool air from the high pressure centre section of the front bumper.
The final point worth noting is the behaviour of the airflow over the front of the car. When it comes to the placement of NACA ducts etc. most people just align them parallel with the car's centreline. Depending on where these ducts are placed however, you may not be getting the most efficient use out of them. Look at the streamlines over the bonnet. Yes, they are parallel in the centre section of the car but look at the change in direction towards the outermost section of the windscreen. As the air flows over the A-pillars a very low pressure vortex is created which attracts the air flowing over the bonnet in that area, creating the change in direction as shown. Placing a parallel NACA duct in this area wouldn't be the best of ideas as the airflow will actually be going across the duct at an angle and not feeding it directly as intended. It's my plan to use these ducts, so I'll therefore have to check their placement with the picture shown and rotate them to face the on-coming airflow as necessary. Next up- rear wing design!