I submitted an article to GRM, but I guess they weren't interested in publishing it. So I posted it on my site https://occamsracers.com/. I think GRM readers will appreciate this, it's as scientific as we could make it. Start on the Results menu.
Here are some quick facts:
- A 9 Lives Racing Big Wang generates 2.5x more downforce when used with an OEM hardtop than with an open top. Even at autocross speeds, you should probably use a hardtop if you're using a wing.
- Removing the rear window from the OEM top is not a good idea if you're using a wing. It performs about as well as an open top when you do that.
- My DIY fastback helped the wing perform better, it generated 20% more downforce, and 15% less drag (.41 vs .48) vs OEM hard top. With the full aero kit (wing, airdam, splitter), the L/D ratio of the fastback was 2.97, the OEM hard top 2.11.
- A 4" splitter reduced drag and increased front downforce by a substantial margin over an airdam alone. The Cl F delta was .38.
- AirTab vortex generators increased drag and decreased the effectiveness of the wing by about 20%. Don't do it.
- The 9LR beat the pants off an eBay double-decker wing, even after I had modified the cheap wing.
- I ran an 8-hour endurance racing simulation in OptimumLap, and every configuration with a wing, beat every configuration without a wing. The fastback won by a lot.
Special thanks to the test team: Jeremiah Wennermark (Man & Machine Consulting), and drivers Anthony Zwain, and Evan Merrill.
