Thoughts on maximizing downforce vs minimizing drag at high speeds?

I've run a couple of club-level sports racers with big rear wings, and my take is that drag matters more than most people think. On paper a huge wing gives you grip everywhere, but in practice the car that loses the least speed down the straights is usually the one that wins the race. You can carry hero pace through a corner and give it all back twice before the next braking zone.

What I learned from my own setup was that wing angle is the real dial, not wing size. I could run the same element flatter and pick up straight-line speed, then lean on the diffuser and underbody for the low-speed grip. The big low-hanging wings on those Group C cars worked partly because the whole underfloor was doing a ton of the work, so the wing didn't have to carry everything alone.

Also worth remembering those cars were designed around fuel economy and stint length in endurance racing, so pure maximum downforce was never really the goal. A cleaner car burns less fuel and puts less stress on the engine at full throttle for hours.

If I were designing something with that kind of power today, I'd start with the smallest wing that keeps the rear stable under braking, then work up from there. Track layout decides the rest. A place like Le Mans punishes drag way harder than a tight road course ever would.

I'd push back a bit on the idea that those wings were a compromise at all. I help out with a historic racing group that runs Group C style cars at demo events, and the old hands there always told me the low-hanging wing wasn't just bolted on for grip, it was there to make the whole underbody work. The wing sat low and wide partly to manage the airflow coming off the back and keep the tunnels and diffuser pulling properly, so the wing and floor were really one system. Shrink the wing and you don't just lose rear grip, the whole balance goes off and the car gets nervous on entry.

The other thing people forget is the fuel consumption rules of that era. Those cars were lifting and coasting and saving fuel every lap anyway, so extra drag on the straights cost less than it would today. What actually wrecked lap times was wheelspin on corner exit and the rear stepping out in the fast sweepers when the car was running a skinny wing.

My own seat time is only in sims, mostly iRacing, but running those Group C cars taught me the same lesson. Minimum wing feels quick untill you get to the long, fast corners, and then you're basially a passenger praying the rear holds.

One thing I never see discussed is that those wings were wide because the rules effectively capped how high they coud sit, so the designers went outboard instead. A long, shallow wing is actualy more efficient per unit of load than a short stubby one, which is why the biggest-looking wings were not necessarily the draggiest. I noticed this messing with slot car aero of all things, where a full-width flat plate lost less top speed than a narrow steep one making the same downforce. Makes me wonder wheather the visual bulk of those 3.5L cars is misleading us about the actual drag they carried.

Total beginner here but I watched a bunch of old race footage lately and one thing stood out. Those cars seemed to twitch and go sideways way more than modern ones, especally when they got close behind another car. I'm guessing the big wing makes a bunch of messed up air behind it? So following someone would mess with the grip at the back. If that's true, does a wider flatter wing make that problem worse or better for the car behind?

Update: after reading through these replies I finally get it. The point about the rules capping wing height, so designers went wider and lower instead, relly clicked for me. Same with the comment that the low wing was there to make the underbody work, not just bolt-on grip. So the huge wings weren't a drag compromise at all, they were part of the whole aero package. Mystery solved, thanks all.