Front air dam

[Arquemann]

Thick plastic sheet from the core support back would be pretty simple. Boxes are old cars, so it's easier said than done. Lower control arm pivot points are close to eachother and generally the underside isnt flat at all.

Basic aerodynamics arent that special, but maximum benefits are really hard to achieve.
Unless you're going crazy with it, probably no need to worry about air flow after the radiator.

Reducing air going under the car could be helped with a proper splitter aswell. @Mr Bean 's MGM has a volvo front air dam, it might even be functional, consider how low the car is. Cool as hell regardless, and something I might do aswell since volvo parts are plentiful here.

[Dragonwagon]

If you make one from aluminum, be prepared to fix or replace it every time you go over a speed bump or steep driveway.

[sly]

If you include the risers from the later versions (I may be imagining this and it may be build your own), they work great as splash shields to keep water off the accessory belt as well as helping with nose aero.

[sick88tbird]

Because I like bringing threads back from the precipice… one thing to remember is that the engine bay is like a parachute. Most of the air pressure that goes in has to find a way out, whether it be through the wheel wells or against the firewall and down and out from underneath. Putting too good of a belly pan on(with no other changes) could potentially reduce cooling capacity. The addition of decent hood vents will help alleviate a pressure build up in the engine bay as well as improve cooling… that coupled with a serious belly pan could negate lift to the extent that it may actually create a small amount of downforce. ANY reduction in lift will pay dividends at 80+mph and the car will also be much less prone to wander when hit with cross-winds.

My Tudor will be getting a complete flat bottom(except for the obvious, like control arms and the rear end) that will taper into a rear diffuser. There will be a ton of other aero touches that’ll go with it, but a splitter will likely not be on the list, not for street duty anyway. There are relatively simple ways of measuring the results indirectly that are much cheaper than renting wind tunnel time, but require meticulous consistency and recording of data. Most people just want a cool looking splitter, air dam, or combination of the two though and rigorous data logging isn’t something of interest.

[sly]

So true. I remember the box hood "waving in the breeze" when I would get over 80mph. Managed to tighten up the corner stops in relation to the catch and that stopped, but it was still a large vibration maker.

[massacre]

Great thread.
I always thought the air dam in the front was because the Aero Vics didn't have much of a grille opening, the air dam catches air and directs it to the radiator?

[gadget73]

yeah it does that too. If its not getting in through a hole in front of the radiator, it has to get scooped from under the car.

[P72Ford]

Many years ago I was looking for one of the factory air dams and couldn't find one. I ended up having a local fab shop bend me one out of aluminum, but I never installed it (was intended for the red P72). Not sure where that ever went off too, but it was a 3" dam, angled forward 30 degrees from vertical to scoop the air. I had intended to powder coat it black. To David's point, it almost certainly would have made jacking the car from the front crossmember a nuisance.