[freebeard]

Dick said vortices come from lift/downforce

It's hard for me to accept that. Lift/drag is a summary action on the center of pressure vs center of mass.

edit:
Well, I've only read the introduction to this, but he stakes out a big claim.

https://professionalawesome.com/diy-downforce/

DIY Downforce – How to Design Front Splitters, Diffusers, Flat Bottoms, Wings and more!
july 9, 2018 by dan, posted in aerodynamics, testing

We see people saying that trying to improve downforce for lower power cars is a waste of time because the cars don’t have the horsepower to make up for the added drag. There may be instances where this may be true, but we have seen this isn’t often the case. We’ve worked with 90 hp Mazda Miatas and 1000 hp Mitsubishi Evolutions. The information applies for both. You can make downforce without adding much drag, and in some cases, even reducing drag!
....
We’re going to start at the front of the car and work our way to back. I know when I first started getting into upgrading aero, getting the front to perform was always my biggest fear. At the back of the car, you could slap on a wing and make it as big as your wallet allowed. But how do you get more performance out of the front? Well, after years of reading, testing and research, my mindset has flipped. Downforce at the front of a car is relatively easy! Why? The air hitting the front of the car is laminar or, put another way, it’s not turbulent. The rear of the car is dealing with all sorts of vortices, boundary layer effects and issues that you really need CFD or a wind tunnel to study. Without having those issues to deal with, designing for the front is much easier.

I'll see how it does, but first— food and hygiene.