I wanted to add a fresh air vent to the drivers side of my Mk 3 but I didn't like most of the installations I saw- 3" duct mounted fairly high in the engine bay.
With the car up on a lift, it looked like a 2" duct would nestle along the frame below the lower A-arm.
It does.
Here what I wound up with. I used 2" stainless exhaust pipe I had, some 2" defroster duct, and a repurposed Explorer throttle body for a control valve.
Nicely done. I would keep my eye open for an inlet piece to gather air from the entire opening.
Yes- I could use the brake duct inlets but I'm not sure that will be necessary. I haven't had a chance to try it out yet due to a sprained left ankle and cold weather.
Interesting idea on the throttle body. I used exhaust cutouts for mine.
My opinion is you should put mesh in both cosmetically and functionally. The only issue I see is that the tube will likely end up with a lot of sand and dirt in the low spot. It would only be a 1 minute maintenance item though.