venting underbody air into trailing wake
 

i read on here somewhere about venting the underbody air into the trailing wake. i was thinking about drilling a 6in. hole in back bumper behind each wheel. maybe hot glue some open mesh on inside of bumper to help with looks. wondering if anyone has thoughts on this.

I have something like that on my car for the front wheels. I cut the inside of my plastic fender linings and have the air vent out the sides.
In my case most likely useless, and might have actually made things worse.
I'll post an image later since I'm using my phone to create this post.
Racers ( or is it ricers ) do the back bumper thing a lot on their cars, but from what others have said here, it doesn't help and just makes your car look silly.
Better to go with a bellypan.

the belly pan sounds good until you get to the suspension arms. plus my wheel wells are open to the muffler and the rear bumper. maybe a combination,wheel wells with skirts and bellypan is still going to trap air

just an after thought,if no fe gains no sence in doing it. as far as looking silly check out any car with homemade kamm back and skirts. i know i get loads of smiles,head shaking and questions

On a similar note, I've been wondering if having a wing hung from the rear bumper would help fill the wake ?
Would the drag from the angle of the wing be cancelled by the wake filling effect on a van ?

The air for that wind would have to come from somewhere. If there ain't enough of it it'll have turbulence just as before. That's the problem with being next to the ground.

6" holes will not flow much air

BamZipPow used 2 piesce of mesh from a gutter guard to vent his underbelly.
Looks about 8"X16".
It would help if the bumper cover is acting like a parachute.
I agree that it would be better to direct the air below it though not through it, less resistance, which we all know is futile ;)