underbody belly pan DIYing, rust from bolt/screw holes?

[freebeard]

For removable panels: strips of Velcro

For permanent mounting blocks or panels: the double sided tape used to attach trim pieces.

[ECONORAM]

Originally Posted by Sven7

Do an air dam and add pans under the engine bay and behind the rear axle. The minimal gains you're likely to see by doing a full belly pan instead of the former aren't worth it in my opinion. Use only existing holes when mounting stuff.

Roofing tar sounds promising but I still wouldn't chance it.

I used the same principle on mine. Avoided drilling any holes in the truck; used holes or bolts already in place, fabbed brackets to support the panels from L-angle metal (flat straps flop around too much to suit me). Had pretty good results with the first half of the truck covered. Did a full belly and didn't see much difference.
Be sure of what bolts you loosen though. I loosened two that required a new front end alignment. WHoops.

[slowmover]

Cibolo, hmmm . . . just outside Selma, TX, one of the most notorious speed traps in the US going back to the 1970's. One of the reasons I used US-281 to go back and forth from Dallas during college in San Antonio.

As to drilling: todays car paint is in layers which work together. For installing radio transceivers one of the old recommendations was to sand metal for vehicle bonds to bare metal. Not any more.

Some form of bellypan will eventually go on my CTD. But, as with component access and cooling needs, a bit more homework will have to be done. Drilling into painted metal not such an easy thing anymore, IMO.

[ECONORAM]

Yep, we are close to Selma. I do see Troopers on the roadside pretty routinely. 281 is a good alternate to I-35.
As for the belly panels, I have successfully used nylon tie-wraps, bailing wire, metal screws and brackets to secure various test panels in place. Self-adhesive velcro did not work. Duct tape doesn't hang on very long either. Packing tape does better.
I fabbed brackets from the front lower frame all the way back to the rear axle, plus a couple on my nerf bars to hold side-skirts on, plus a few more to hold my wheel flares in place.
I've used a couple of 3x4 pieces of .050 aluminum for the eng bay and under the tranny, but I really need to cut a couple access panels in it for oil changes. Although, I plan to replace the eng bay panel with some 1/8 ABS plastic.

[brucepick]

Building the belly pan on my '97 Civic (same generation as yours) I had to put only one screw into metal. All other fasteners went into either the plastic side skirts or into the front and rear bumper covers.

In some areas I did use 1/16" or 1/8" aluminum bar stock to create a frame. I attached the frame to plastic at the car's outer perimeter as noted above and then pop riveted the aero panels to the frame. You need washers on the visible side of those rivets because neither Coroplast nor aluminum flashing will hold a rivet just by itself.

[mcrews]

Can't see velcor holding.
I have over 80k miles on underbelly pans on the Q45.
you cant underestimate the force of the air moving around the car.

[a8ksh4]

I'm in the middle of the road on this one... I don't mind drilling into the bed on my truck for mounting stuff, but I wouldn't touch the frame. I might be okay will drilling into underbody panels on a uni-body car if I had access to the holes on the inside so I could weld on backup nuts/plates and seal.

Best thing under the engine bay might be to weld on a bunch of zeus clip fasteners so that the panel could be removed without tools for cleaning and maintenance.

[1carnut]

I did front and rear coroplast pans over the weekend. i attached the front of the front one to the existing plastic but the back was a head scratcher for me and I ended up mounting a plastic piece that went from side to side on the car and mounting the coroplast to that. I'm not sure how it will hold up. I did drill a couple of holes in the bottom of the car to mount the plastic but my hope is that since the coroplast is there that very little water and salt will get to the holes. I shot the places I drilled with truck bed liner.

[mcrews]

Originally Posted by 1carnut

I did front and rear coroplast pans over the weekend. i attached the front of the front one to the existing plastic but the back was a head scratcher for me and I ended up mounting a plastic piece that went from side to side on the car and mounting the coroplast to that. I'm not sure how it will hold up. I did drill a couple of holes in the bottom of the car to mount the plastic but my hope is that since the coroplast is there that very little water and salt will get to the holes. I shot the places I drilled with truck bed liner.

I have some pretty detailed pics of my intallations in my signature

[ECONORAM]

Originally Posted by mcrews

Can't see velcor holding.
I have over 80k miles on underbelly pans on the Q45.
you cant underestimate the force of the air moving around the car.

That is very true. My first set didn't make it across the state of Wyoming. We had a gust of wind that tore the vinyl panels right through the screws I was holding the panels on with.
You ought to see the aero forces at work on the front wheels! I've lost or torn 6 wheel covers on the front because of them.