Wind Tunnel Testing

I was at the A2 wind tunnel on Monday, and as I expected, it was an incredible experience. At one point in the middle of the test I said “Geoff, is that doing anything?” To which he replied in frustration, “Hold on, I just started the test a second ago!” I was like an impatient kid… or maybe a drug addict, I had to have it NOW.

The tests take about 5 minutes to run. The fans operate at something like 640 hp, and spin up quickly, and all that air fiction inside the tunnel makes the garage area (where I was prepping the next parts) very toasty. Winter testing would be a more pleasant experience.

Back inside the control room, the results don’t populate in the spreadsheet right away. There are two sets of monitors, one for Geoff, one for the clients, and both have the data, video, and pictures for monitoring the action as it unfolds.

I was quite fortunate to have AJ Hartman accompany me to the test. He spun wrenches and analyzed data on the fly, and made suggestions on other tests to run. The biggest surprise of the test was one of his suggestions.

I started the test with all of the aero parts on the car, because removing parts is a lot easier than adding them. It went like this:

There were some surprises, probably nothing more so than there were no unexpected delays. Driving down to the test, I fully expected the car to die, or parts to fly off in the tunnel, or anything else that would be catastrophic and absolutely normal in my life. However, we stayed ahead of schedule for the whole test, and did 26 runs in 3.25 hours. Finishing ahead of time saved me $125, so the planning and rushing around during the test was worth it.

Tests done and mistakes made

Before I went to the tunnel, I asked Geoff and AJ what were some common mistakes. One of the most common is taking time to analyze the data, which we didn’t do. And another was not bringing all the parts, or making all the adjustments during the test, and having to come back another time. Guilty.

For one, I should have tested more wing variables. I had all of the wings set to zero degrees, because the roofline goes down at about 10 degrees, and I was afraid if I added too much angle, that the wings would stall. But after looking at the results, I should have done more tests on wing height, setback distance, and angle. I also didn’t build all the parts I wanted to test, including barge boards, rounded B-pillars, front tire spats, air fences, and splitter diffusers.

In the previous post, I listed all of the things I was going to test, but I also got to throw in another test that was very, very important (thanks AJ). In all, I had many more wins than mistakes, and learned far more than I thought I would. I had some assumptions I was wrong about, and some I was right about, and an equal number of surprises that showed me just how fun this game really is.

Results

You’re probably wondering when and how I will release the results. I’ll likely host a webinar so that I can walk through the data, and then we can also do questions and answers. The latter would be a great way to find out what people want me to test next. Along with the webinar, I’ll release a data sheet explaining all of the results. It won’t be free or a cup of coffee, tho.

This test took a lot of preparation and parts building. It was a 22 hour drive round trip, plus a hotel, shitty road food, gas, wear and tear, etc. Some of the things I tested will absolutely make your car faster, and some of you are doing things that are making your car slower. Whatever this webinar and data sheet costs, it’ll be the best money you can spend on performance (with the exception of data coaching).

I think most people are busy racing right now and aren’t going to change their cars much, so I’ll do the webinar this winter, which gives people time to modify their cars for 2024. I will likely hit the wind tunnel one more time to fill in some of the gaps, and so waiting may also bring about some refinement of the data.

If you absolutely need to know the results before then, contact me and we can work out a fee for aero consultation. I’m not in this for the money, but I’m sure you understand that I’d like to break even on the cost of wind tunnel testing. And I don’t want you to share the data, because this shit is worth seconds per lap.