Ok, time for a post re: my experience adding a rear wing to my Coupe.

You may know that I’ve been running/tracking using the aero nose alone. Somehow, I got the itch to add a wing and see if it would affect handling/lap times at the track.

70” wing is from https://wing-logic.com/

What’s cool is the data sheets behind this that have a table and plot downforce/drag vs. speed and angle of attack. I was aiming for 200 lbs of downforce at 100 mph and willing to give up some hp to drag.

My design goals were to have the wing removable and be able to revert back to the spoiler easily. I fab’d up the mounts which are bolted the rear car frame (4 bolts each with backing plates)- these do not need to be removed and I may weld them in someday.

The ‘intermediate’ mounts run in a C-channel and are height adjustable. The C-channel as well as the triangulated gussets on both sides of the channel make the whole thing very rigid in all directions. I chose an arbitrary height that I thought looked good. The hang test gave me some level of confidence as to the strength of the setup.

The trick now is setting the wing angle- easy if air is flowing parallel to the ground but it’s not.

Some camera angles of airflow with the wing angle of attach set zero degrees to the ground:
360 view (click and drag to change the view) https://youtu.be/zfFhnhABGrE
Under-wing: https://youtu.be/imD5VXnKwMs

The main goal here was to make sure that the wing was not stalled (angle of attack too great) and that the airflow was smooth along the underside of the wing – which it was.

I ended up with the wing at zero degrees to the ground, knowing that the air off that rear glass would be coming down at an angle, while more level towards the ends of the wings.
The driving test was at Thunderhill Raceway: 3, 20-minute sessions without the wing (with spoiler) and 2 sessions with the wing (no spoiler). Not an ideal A:B:A test but that’s what I did.

My impression after the first session out with the wing was that the car felt more stable but my lap times were identical to the previous session (best times from each 20-minute session). I think that I had trained myself to drive the car a certain way and that I needed to push it in the next session, which I did. The car usually had oversteer tendencies (even with no rear sway bar and the front on full-stiff), both on the gas and on the brake. In the 2nd and final session with the wing I crept up in the car’s handling limits- Thunderhill is good for this as it has some 3-4th gear sweepers where you can really test out the effect of throttle.

Some plots here: https://youtu.be/e79DbGVWQow

In the end it felt as if I could brake later and charge the car into a corner harder with more confidence and carry a bit more speed through and coming out the corners. I would not enjoy tracking the car without the wing. I think that there is more lap time to shave but I’ll have to re-learn how to drive the car (not needing to be as timid as before).

In the plots you can see how the red car (wing) outperforms the blue (no wing) car which adds up to ~3 seconds per lap. The red car out-Gs the blue car in all areas of the track. Top speeds were nearly the same which I’m assuming is due to being able to hold the gas down longer and brake later.

In the end I’m happy with it. Next up will be to add a splitter below the aero nose and perhaps try some wing angle testing.

Dave
Gen III Coupe #17
16,000+ miles

bracket 1.jpgbracket in place.jpgwing 1.jpgwing 2.jpgwing 3.jpg

G1.pngG2.pngno wing lap.pngwing hang.jpgwing lap.png