Frontier pickup belly pan project
 

I am currently working on what I hope to be a full or nearly full belly pan on my pickup. I will use this thread to document my progress and ask for suggestions and help as I go.


So far, I filled the large gap between the bumper valance and the factory plastic front under body pan up front and boxed off the front corners of the bumper valance. I also capped the front light holes and used body fill to effectively erase them from my front end. I can tell the difference already in sound and throttle load at high speed which is giving me the encouragement to keep going. Since the truck is relatively tall, even with 2" of suspension drop, I am going to try to maintain my ground clearance and go for what I would call the "high and smooth" approach. I am not willing to drop the truck any lower since I would loose my remaining suspension travel without expensive drop spindles.

My biggest question right now is how I am going to deal with the rear axle. The leaf springs will be quite a challenge as well. The rear bumper currently acts as a parachute. The rear axle back is a disaster really... I guess I will cross that bridge when I get there but suggestions and examples would be greatly appreciated!

Fog light shave:
http://carphotos.cardomain.com/ride_...4008_large.jpg
http://carphotos.cardomain.com/ride_...4017_large.jpg
http://carphotos.cardomain.com/ride_...4018_large.jpg
http://carphotos.cardomain.com/ride_...4057_large.jpg

Bumper gap and and corner box-off:

Before:
http://carphotos.cardomain.com/ride_...4053_large.jpg

After:
http://carphotos.cardomain.com/ride_...4055_large.jpg
http://carphotos.cardomain.com/ride_...4056_large.jpg

And getting started on side skirts:

Before:
http://carphotos.cardomain.com/ride_...4060_large.jpg

After:
http://carphotos.cardomain.com/ride_...4058_large.jpg

THIS should get interesting:
http://carphotos.cardomain.com/ride_...4052_large.jpg
http://carphotos.cardomain.com/ride_...4061_large.jpg

Look at all that mess under there (in the last 2 pics). When that gets 'filled in', along with what you've already been working on, you should see a good improvement in MPG.

You could put vertical fences on the insides of the leaf springs.
The belly pan can then go a bit higher up between these fences.
The front of such a fence can form the inner line of a fairing that shields the rear wheel/spring ; the rear end can become part of a boattail for the wheel/spring.

The differential can go under a bulged streamlined fairing of its own.
Mind the vertical travel of the diff. , or eliminate that by attaching the aft belly pan to the rear axle.
In the later case, the belly pan will need somewhere to pivot and will need some play to make up for the vertical movement.

It looks like the front bumper is still higher than the lowest suspension parts.
If so, you'd still benefit from an air dam that extends down at least as low as the lowest underbody part.

I have the same truck,

Did you notice any difference in coolant temps when you did the upper grill block? I have been considering doing the same, but I often use my truck pretty rigourously and overheating is a concern (similar climate to yours).

I'm planning on ducting the fog lights to the front brakes for cooling, as I have overheated them a couple of times on some steep mountain roads.

I'm already missing the front plastic belly pan due to a few not so well placed rocks.

At least your rear bumper is still straight, mines been worked over pretty good. Darn shrubberies!

To do my belly pan I was planning on cutting small pieces of angle iron and welding them to the frame, then drilling and tapping holes in the angle to allow me to bolt on the pan.

I am planning on the same concept only I will be using 1 X 1 X 1/16" aluminum with threaded inserts and/or plastic panel rivets (the resuable automotive type). The aluminum is very light , stiff, and inexpensive. I just picked up a 16 foot stick for $15 at the local industrial metal supply. I am using self tapping screws to secure the chloroplast to the steel frame. My install is inteded for street use only however!

The automatic grill block I am trying out is working out well! I have seen my coolant temperature actually fall recently with it installed since it is now only 95 degrees rather than 110. The engine temps have been in the high 180's to 190. The grill block remains open untill I hit about 50 MPH and the force of the wind will then force it shut. I designed it to do that so if you are pulling a load up a grade and your not going very fast, you will still have full cooling. If you are goning fast enough to shut it, the air velocity should provide enough cooling to the remaining open lower grill. Even though the whole lower bumper is sealed off now rather than open, I still get more than enough cooling. I still have not closed off enough to cause any higher temps than factory. I may close off part or all of the lower girll so find the "tipping point".

I have one complete side skirt done! Next is the rear wheel well. I am pleased with the results. The framework for the wheel well covering is ready to go. Took me about 6 hours. The other side will go faster.

http://carphotos.cardomain.com/ride_...4063_large.jpg
http://carphotos.cardomain.com/ride_...4064_large.jpg
http://carphotos.cardomain.com/ride_...4062_large.jpg

I fear I underestimated the amount of spplies this project would require; I am running dangerously low on cold beer.. Don't let this happen to you! If you plan on attempting a similar task, stock up ahead of time. ;)

BamZipPow seems to be doing well with c-plast on the rear undercarriage of his little pickemup.

I'm hoping to do a little aero stuff at the end of this year. Guess I better get on it since your cpm is now the same as mine, ha!

Your truck is not doing too bad for wieghing TWICE as much as mine and putting out at least 3X the HP... Holly smokes!

Yes, banzippow did a very nice job on his truck and helped inspire me to take this job on. So far it has been very labor intensive but also very rewarding. My current tank is absolutely destroying my last and so far it looks like I am on track for 29+ mpg! Should be able to hit 400 miles on this tank which is something I have never done. My goal is 30 consistently and that goal is becoming within reach.