Belly Pan slowing me down
 

I installed a belly pan on my Hyundai Elantra last week out of coroplast. Ever since I did my mpg numbers have gone down. It feels like I have a lot more drag with it on. I do not have a front grill or bumper block. I am wondering if the air that goes into the engine bay gets stuck in there with now where to escape because the underside of the engine bay is completely covered? and the only place for it to go is back out the front of the car.

Any one have this problem before?

I am going to try a bumper block with some left over coroplast.

wildfire8 -

That's the first I have heard of a belly pan "gone bad". Do you have pictures of your configuration? Without seeing the details, I am guessing that you are experiencing a "parachute effect" where the air is getting stuck in the pan somewhere. I would shoot pictures from the POV of the airstream. Find and close whatever hole is causing the problem, and the belly pan will start working as intended.

CarloSW2

Hi,

I think you need to do an upper grill block, and probably a partial lower grill block, too. I also had this happen, when I taped up the opening in the chin pan -- it was dragging me down, and now that I have a smaller grill opening, it may be helpful to block the under pan again.

here are some pictures.

1 front of car
2 front of belly pan
3 front hooked to the bumper
4 showing all the way back (cut a hole for the tow hook) (the hole in the back is for the CAT)
5 showing the cut away for my tire from the front
the next pics are in next post.
6 the hole in the back is for the CAT so it wont melt
7 pic from side of car showing the back of the belly pan.
8 showing the cut away for my tire from the back

pics 6 7 8

make sure that there is an opening under the engine compartment that is at least as big as all the frontal openings from where the air can penetrate into the compartment. also make sure the opening is placed as far back as possible.
but i would consider reducing the frontal openings aswell.

now it seems your pan traps the air or slows it down, turning your car into a parashute. at best it slows you down, at worst it could blow off your pan at high speed so beware.

Hi,

Add an upper grill block! And I'd cover ~ half of the lower opening too -- the outside part, and experiment with leaving some open near the lower center. On my car, I only have about 1/5 of the original grill opening left open, and the cooling is fine.

even if i do a bumper block i will still need to have an opening?

i don't have a belly pan yet myself, but common sense tells me it's not a bad idea to have some opening underneath. make the opening on a horizontal or rear upward sloping part, so that the air going under the car doesn't enter through there. i would still leave a partial opening in the front grille so that there is a minimal airflow wich should avoid air from coming in from underneath and messing up your cooling and aerodynamics.

Can't believe people are telling him to block the grill, with the Utah summer a week away...

Why not just make some holes in it?