Here's the overview of what I want to achieve aero-wise:
As a fan of aero design, the MSA Britcar Championship was deliberately chosen as the aero regulations have minimal restrictions- allowing me to design an aero package specifically for the Z3 and exactly how I want to.
So long as the aero devices don't extend more than 100mm fore/aft of the length of the car and aren't wider than the original bodywork, pretty much anything goes!
We've already seen that the car is struggling with power and with this in mind, I'm aiming for a fairly simple concept that will increase overall downforce as efficiently as possible, but without incurring large drag penalties. Sadly, as much as I'd want to, I can't get too carried away with limitless-restriction aero designs - as per DTM!
It's also important to remember the front/rear static weight distribution of the car that we also saw earlier. I'm aiming for a 50/50 centre of gravity split, so this also has to be the aim for the aero centre of pressure. What this means is that the downforce developed over the front axle has to equal that of the rear. Otherwise, we'll end up with high-speed handling characteristics that don't match the low-speed dynamics. For example, a car that feels neutral and well balanced on the low speed corners due to the mechanical grip alone, but understeers/oversteers at high speeds if the centre of pressure is too far rearwards/forwards. All in all, this makes for a pretty unbalanced and unpredictably handling race car!
Whilst it's pretty easy to generate large amounts of rear downforce - massive wings, large venturi tunnel diffusers etc. - it's not so easy to generate large amounts of front-end downforce on a tin-top car. Therefore, I'm starting with the front of the car and will try to get as much downforce as I can out of it via the splitter, dive planes and small diffusers hidden in the splitter. It's also important to remember manufacturing cost throughout all of this, so I'll be looking to see if the gains in downforce are actually worth it.
With the front-end sorted I'll then move onto the rear and tune it to match the front, thereby hopefully keeping the 50/50 centre of pressure.
I'll go into more detail in the next update as to why I've gone for "swan neck" wing supports and other design features etc., once I've made a start on the CFD analysis.