TexasLT1

Has anyone ever made under body panels for airflow control? I realize for a truly effective system you would need windtunnel access, but just wondering if anyone has ever made any just for the hell of it.

*Yes, I'm bored and the gears are turning in the head*

Rage13

i've been thinking about this idea for a little while, need to get the car on a lift to see how it could be done well. still trying to figure if it would be better to make out of aluminum or fiberglass.

i've also heard that putting a belly pan on a car thats to high in the air will cause lift, anyone else ever hear of this?

85VortecTA

Ff you made flat body panels underneath the car, focusing on the front piece under the nose, wouldn't it over heat our cars since the damn would no longe rbe there and no way for air to enter the radiator area??

Especially on a TA or Firebird.

still a cool idea

Rage13

could put a scoop under the car to catch air for the rad and just have to duct it in and out of the car. would also help keep more air from getting under the car too

lonsal

iTrader: (2)

I made custom panels to smooth the air flow under my Camaro convertible a few years ago. I was inspired by the under panels on a Firebird. As to air flow for the radiator, I solved that problem by cuttining a window that leaves the stock air flow area before the lower dam open. I mounted a power steering and oil cooler in this area. I used sheet gray pvc material and aluminum angle stock to reinforce the panels. The outer edges are screwed to the lip of the front spoiler. The panels extend as far back as the end of the front spoiler. I have an attachent point at the front sway bar using an old sway bar bushing and zip ties to a custom aluminum bracket. You can't see these panels at all from above. You have to look below to see them. I think it cuts down un under-car turbulence, but I have no practical way to verify that short of renting time in a wind tunnel. Like THAT's gonna happen! lol. I'll look for pictures and see about posting them.

Oh, before anyone asks why I didn't make this available as a TDS product. The material cost alone was around $100 as I recall.

Lon

TexasLT1

Awesome, thanks Lon.

also, I just found this interesting photo on openroadracing.com, check out the red camaro on the right side of the pic. Yeah I know its small, but its all they've got on there.

TexasLT1

just found this, not the same one in the photo above, but quite interesting nonetheless. I'll see if I can get any more info about the car. Notice the rear air extractors....

z28monster

iTrader: (1)

that grill looks kind of cool on there

TexasLT1

Yeah it does, I'm just trying to figure out a way I could put something like that on without having to screw into the front facia.

On another note, anyone have ideas about materials to make the belly pans out of? Sheet metal comes to mind first, but they have the disadvantage of added weight.

I like Lon's idea of PVC sheet, but exhaust and engine/trans heat concern me with that idea. Fiberglass/carbon fiber also come to mind, but I would think they would need stiffeners/support of some kind. It wouldn't be all that hard to mold these into the sheets, but its just something else to worry about it. On the other hand though, some sort of plastic would be more resilient to dents and dings whereas the sheet metal would get all dinged up and become pointless....

Hmmm.....

askulte

I've been thinking quite a bit about that as well.

Consider exhaust heat. If it's above the plates, it will be in dead air, and will not be cooled. That will definitely increase the amount of heat to the inside of the car, since the exhaust pipe is roughly 1" from the floorboards. Ceramic coating should take care of that issue.

Some aluminum sheetmetal should be fine. Make an 1/8" "X" bead to give it some strength. Attach to unibody w/ dzus fasteners to make it easy to attach/remove (we did that on the TransAm series Corvette).

I don't know how much it will help, unless you make the whole underbody flat. How to deal w/ the rear axle area? A rear diffuser would be nice. I've seen some pictures (a 3rd gen open road racer was featured in one of the mainstream hotrod magazines a few years ago).

I really want to get some displacement transducers rigged to the struts/shocks, and get accurate downforce readings. Before and after would be nice...

TexasLT1

I've been trying to come up with a way to do that as well, but I just can't see an easy way without switching to IRS rear, which just doesn't seem worth the work for something like this. I was definitely thinking about the ceramic coating for the exhaust, its just makes sense.

Where would one be able to get access to the equipment like that to measure downforce? I think I'll go talk to some of my engineering instructors and see if we have the equipment here, or if we could get it.

askulte

If you get LVDT (distance transducers), just mount the top to the shock body, and bottom to the shock rod. A movement in shocks (front or rear, or both) will correspond to downforce if it's due to a higher speed. You just simply measure how much the car sinks as you go faster. Lasers can work too, if your fancy!

Andris

TexasLT1

Hmm....I think I could definitely come up with something to measure that. Just do it for a long enough distance and you would see an easy trend to cancel out road bumps and stuff, then just compare before and after.

Once you have the measurement though, how would you convert the difference in ride height into downforce?

askulte

You know your spring rates (say 900lb/in up front and 175 in the rear). If at 100 mph the nose drops 1/2" and rear drops 3/4", then you know downforce.

900 lb/in * .5 in = 450 lbs front downforce

You do have to be careful to always have some positive or zero rake in the car. If the rear of the underbody plane is lower than the front, you'll get lift. With softer rear springs, it's something to consider, since the rear will get sucked down more than the front with the same downforce. Data is good.

Andris

TexasLT1

Duh. wasn't even thinking about that. I definitely want to try this now