Belly pan for f-150 4x4 truck
 

I would really like to smooth the underside of my truck as a lot of air passes under (ground clearance is high and is needed off road so no lowering). I plan on extending the air-dam a little but again need the clearance. I have covered the gap between the body and frame rails with some thin polyethylene sheeting. I am curious if anyone has any advise on negotiating the drive shaft and rear axle on a truck ( has an independent front suspension). I know a couple of members have put belly pans on trucks but have never seen a picture of that part. I have some skid plates that came from the factory in the front and under the gas tank and am thinking of a pan from the back of the transfer case to the front air dam and a rear piece that starts tucked up behind the rear axle and angles up to the rear bumper covering the spare. maybe an aluminum panel over the exhaust.

I plan on an aerocap in the future, but right now it has a snugtop cab-high canopy. I jack the tire pressure up on the highway and obsess over the scan gauge. In this configuration I am consistently getting 21 mpg on the highway-way worse in tow, with the 4.6l v8 auto (scan gauge and hand calculations).

what's all done to the truck? motor wise and transmission wise is it stock? And i understand you need the clearance for offfroad but do you really need 4WD?

drive shaft clearence
 

you do the pan the same as on a front drive car, except you leave the drive shaft exposed, atleast at a point where it drops lower than your pan which will be tucked up higher. i have a 1990 f150 4x4 have not panned it but looking at it you will need to leave a cutout for the transfer case also,, i would use self tapping sheet metal screws with big fender washers on the frame rails. watch your brake and fuel lines. those big rear leaf springs are another thing that cant be covered,you have alot of pattern cutting to do, but if you do it right, it could make a noticeable difference especialy if you combine it with grill block,mirror reduction or delete, but you also probably know that the rear is where the biggest gains are hiding, (aerocap,,,etc)

sleeper what about a heinged, cable operated air dam you could go really low with it and just tuck it back up for off road? just an idea.

Is there a transfer case skid available for your truck? If you got one of those it would be easy to tie together the front skid plate and the t-case skid.

Thanks for the replys,

Domman56,

Yes the 4x4 is an important part of this truck. It is all stock, I have a partial upper grill block and the body to frame rails covered underneath. I run the tires at 40 psi on the highway.

Moonmonkey,

An easy to remove air dam might work but I worry that with a high ground clearance I may increase the frontal area so much that I would be better off with a smooth underside.

I am trying to decide if I want to fair the axle with an upside down airfoil shape behind it tapering to the bumper in the hopes that the air disturbed by the axle will reattach or if should just make a flat panel under the frame rails. I just haven't ever seen this attempted. The angle should eliminate any clearance issues...

If you try to fair the axle, you'll rip that fairing off on the trail

You should check out what I did fer a belly pan on my Toyota T-100...maybe it will give you some ideas! ;)

I would use something like my custom brackets...makes it easy to not make mistakes in yer frame. :D

Nice work BamZipPow.

I doubt the luan will last too long but it will make a righteous pattern for another - more durable - material.

It's just a test bed...luan is cheap, easy to git, and easy to work with. :D