Front air dam cross section

[Bill in Houston]

Bruce, I feel your pain. I had all of those questions when I built mine. I vote no on the splitter (since it's more for downforce), and yes on having it as far forward as possible. Beyond that, I have no idea. Sorry.

[caprice]

Originally Posted by basjoos

Since your air dam is downwind of the leading edge of your bumper, you are going to have a drag-inducing area of high pressure piling up in front of your air dam no matter how you shape it.

Like this?

[brucepick]

Caprice,

Neat photo-morph!

I think a rearward slope like that would minimize the pressure buildup but would do little to keep air from getting under the car. As I see it keeping air out from underneath is the whole aim here. However of course you want to do that with the minimum penalty possible.

[caprice]

Why are you not belly panning it? Or did I miss that... I was thinking of using an oil drip pan, commonly found at auto parts stores. It is galvanized, and is safe for engine fluids to drip on. Make it so you only have to remove 4 or so bolts on it, so you can still readily access the bottom of the engine. Just an idea.

[brucepick]

I did belly pan, actually. At the front of car only so far. I'll call it a forward belly pan (FBP) to distinguish it from the OEM one which is below the radiator/fan shroud area and reaches under the front of engine.

Forward belly pan's leading edge is cut (curve) to match required curve of air dam.

Air dam lower edge is bracket-attached to the leading edge of forward belly pan. Air dam's side sections are attached also; you can see the three screws in my photos. FBP is 20" front to rear and reaches between the front wheels to meet the OEM belly pan. FBP is cut in to allow the wheels to steer. OEM belly pan extends approx to the front axles so I've got that distance covered.

I'm really hesitant to add sheet goods under the car where all the hardware is. But I do hope to clean-sheet the back end next time the exhaust system needs work. OEM muffler is transverse, just below and forward of the rear bumper so it would be in the way of any smoothing work there. I have a plan to reroute the exhaust with a muffler further forward instead of in the OEM location.