I have a dream.....a local wind tunnel.
 

Auto companies spend millions on high-tech wind tunnels. But why couldn't we develop low-cost, drive-in wind tunnels, on the same model as local car washes or oil-change places? This would probably be a concrete building with 4 bays, and the user could rent a bay for a specific time period and reasonable cost. This would allow the budding EcoModder to see right away if a particular modification is in fact producing the desired result. The interior of the bay would have to tunnel (rounded) in shape, and have powerful fans with horizontal louvers. The last piece of equipment would be a hand-held, wand-like, smoke generator. Where are the entrepneurs that can make this a reality?

Would love to see it happen, but I think it is a pipe dream:(

You are talking about a very large inverstment and very few high paying customers. We here are not representative of the general car buying populace.

Good wind tunnels are extremely expensive, very large and very complicated. Hucho devotes almost 80 pages to their design in his "Aerodynamics of Road Vehicles."

There have been some proposals for homebuilt tunnels adequate to test scale models, but the data does not scale well for small models.

The poor man's wind tunnel is the open highway with tuft testing and video cameras.

To test full size cars the test section of the tunnel would have to be >20' square, the rest of the tunnel, which should recirculate on itself, would be bigger, you would need 1200-2000 horsepower, and it wouldn't be in a suburban location because it would be as noisy as a dragstrip.

All the above is In My Humble Opinion, of course. Otherwise, a great idea.

Would be cool. But that idea would never make money in the current market. Too bad. It would be so much fun!

or............. build tunnels facing the ocean along the louisiana coast and wait for the hurricanes that hit every year.

I was thinking the same thing when I was indoor skydiving a couple years... "why couldn't you take this same hardware and make a test tunnel with it?"

iFLY SF Bay - Indoor Skydiving

A friend and I were talking last night, about using a replica plastic car model in a scale wind tunnel that he heard about.

I like your avatar. Have you posted results and pictures somewhere?

Is it illegal to have chemical smoke trails on US roads?

Why not build a grid array of smoke trails and mount it on your from bumper. Use the smoke trails that that skydivers use, go out on highway and you have a real world wind tunnel better than any tuft testing. You'll even be able to see the actual wake the car leaves behind.

You will need a chase vehicle filming, but it'd be your cheapest best option.

You would have to have virtually no crosswinds though, but depending on cost/ legalities, it could work.

Maybe base the smoke on our FDA approved food dyes?

However whatever the material and color, I would expect anyone seeing it would be sure it was pollution. Unless you're in an isolated area.