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Began with four 2' x 8' pieces of coroplast (corrugated plastic) 4mm thick.
http://img96.imageshack.us/img96/8936/15ze3.jpg (http://imageshack.us)

1. Jack up one side of car and place one sheet underneath.

http://img449.imageshack.us/img449/8672/23zs.jpg (http://imageshack.us)

2. Slide edge of coroplast between black moulding flange and floorboard. Secure with three screws through moulding flange

http://img96.imageshack.us/img96/7430/32mw.jpg (http://imageshack.us)

3. Slide forward until you have enough coroplast to attach to front lip.

http://img449.imageshack.us/img449/2430/45vs.jpg (http://imageshack.us)

4. Cut reliefs into coroplast for clearance around A-arms. Attach to front lip with screws. Duct tape not required but it helps to smooth things out.

http://img449.imageshack.us/img449/2849/59tg.jpg (http://imageshack.us)

5. Bend up and secure coroplast with screws to complete the wheelwell treatment. This helps keep turbulence from wheel well from getting between the bellypan and floorboard. Trim around exhaust system leaving at least 1" clearance between coroplast and any exhaust component.

http://img158.imageshack.us/img158/5837/68ys.jpg (http://imageshack.us)

6. Repeat steps 1-5 on the other side.

To be continued.....

Aero Mod continued....

http://img449.imageshack.us/img449/2135/76ti.jpg (http://imageshack.us)

7. Install coroplast on drivers side rear. Forward end slides between front coroplast piece and floorboard. Rear attaches to rear lip. Secure with screws.

http://img158.imageshack.us/img158/1934/84rl.jpg (http://imageshack.us)

8. Install coroplast on passenger side rear. Leftward end slides between drivers side rear coroplast piece and floorboard. Rear attaches to rear lip. Secure with screws. Trim around exhaust system leaving at least 1" clearance between coroplast and any exhaust component.

http://img158.imageshack.us/img158/9678/95uq.jpg (http://imageshack.us)
Cut reliefs for suspension parts.

http://img449.imageshack.us/img449/1456/107dt.jpg (http://imageshack.us)
http://img449.imageshack.us/img449/2609/113wo.jpg
(http://imageshack.us)

9. Complete passenger side rear wheel well treatment. Trim around exhaust system leaving at least 1" clearance between coroplast and any exhaust component.

http://img158.imageshack.us/img158/7789/129fl.jpg (http://imageshack.us)

10. Complete driver side rear wheel well treatment.

http://img158.imageshack.us/img158/2600/144jp.jpg (http://imageshack.us)

11. Paint all coroplast flat black. Not yet completed.

http://img449.imageshack.us/img449/4540/152mz.jpg (http://imageshack.us)

Enough coroplst left over for wheel skirts and grille block.:D

The first thing that I noticed was, OMG, my car is soooo quiet! I think that a combination less turbulence and the insulative qualities of Coroplast made a very noticeable difference in road noise.

I took a 30 mile RT to get black spray paint and the NGK V Power plugs at Pep Boys as Autozone doesn't carry it. This course yields very similar FE to my daily commute. On one downhill section, I usually start it with engine off at 20 MPH and reach a max speed of 55MPH then coast down to 30-35 before another downhill. Normally I have to bump start to keep speed up (40 MPH zone with cars behind me) before reaching the second downhill and then engine off again. Today my max speed was 62MPH and I made it to the second hill at 35 MPH without restarting. Wooot!

The FE for the 30 mile trip was 62.1 MPG, a new personal best. :D My previous bersonal best was 61.4 with a 10 MPH tailwind. Whats even more impressive was that I had a 15MPH west wind and 53F. Since the route is generally N-S I never had the benefit of a tailwind and was always fighting the crosswind. I'm actually looking forward to work on Monday!

Current Tank: 91 miles, 61.0 MPG :D

Where'd you get it, and at what cost? About how many hours of work does this represent?

I bought it at a sign making shop. Coroplast is what signs are mostly made of these days. I spent $40 on four 2x8 ft sheets. It took about 5 hours total.
Good Luck!

Hi Dan:

___What a beautiful job! The next time I am Pittsburgh way, I think you and I should spend some time under the Accord or better yet, the Ranger! I would love to see the Cd numbers before and after but I can bet you dropped at least 4 – 5/100ths with the drop and the under body aero cover.

___Billy is already purchasing add-ons to improve his upcoming 06 Ranger and that thing would be a prime candidate for your under-body aero-mod treatment. I will PM him with this threads url.

___Good Luck

___Wayne

Yes, stop by any time. You can pick up your sleeping bag!

So do the clips and screws make it reasonably easy to remove for oil changes?

Ive been thinking of doing this to the Accord and Civic. Will be intresting to see how it holds up. And the drop in noise!!!! Thats worth the mod right there. Honda really needs to work on there road noise and acustic properties. :)

WOW: what a very interesting Thread. :) Great Pics. to go with Text. Not to forget the results after the Mod was Performed.

Great Job !!!!! :D

So do the clips and screws make it reasonably easy to remove for oil changes?

I think 3 or 4 screws is all that would need to be romoved for an oil change. Im using Mobil one so I wont be changing oil for a long while.:D

Yesterday I removed the passenger seat, mud flaps, floormat and a 10 lb trim panel in the rear which squeaks anyway. That was good for about 50 lbs. Then I drove to the park which has a road that circumnavigates a lake, about 5 miles per loop. The speed limit is 15-25MPH, 2 stop signs and 2 stop lights. I made two loops at average 20MPH, 5th gear at 600-1000rpm, 60F and I had the roof removed. The SuperMID said 72 MPG! :)

New personal best on the drive to work this morning. Things that have changed are the new belly pan, new side gapped spark plugs, 50 lb weight reduction (I will be putting the seat back in though).

Previous best trip was the "more highway miles route" which is now my preferred route, 50F Dry, 6 MPH headwind, 60.60 MPG.

Today, same route, 54F Wet roads, 10 MPG headwind, 62.75 MPG!

Woot!

I'm guessing that the plugs and weight reduction had a minimal effect. Probably all belly pan aero drag reduction. On dry roads it would have been even better. Also, much less road noise. :)

Current tank, 130 miles, 62.0 MPG. The 72 MPG 10 mile trip around the park yesterday gave me a nice boost.

New personal best on the drive to work this morning. Things that have changed are the new belly pan, new side gapped spark plugs, 50 lb weight reduction (I will be putting the seat back in though).

Previous best trip was the "more highway miles route" which is now my preferred route, 50F Dry, 6 MPH headwind, 60.60 MPG.

Today, same route, 54F Wet roads, 10 MPG headwind, 62.75 MPG!

Woot!

I'm guessing that the plugs and weight reduction had a minimal effect. Probably all belly pan aero drag reduction. On dry roads it would have been even better. Also, much less road noise. :)

Current tank, 130 miles, 62.0 MPG. The 72 MPG 10 mile trip around the park yesterday gave me a nice boost.
Hey;

What can anyone say but this: YIPEEEEEEEEEEE !!!!!!!!!!!! :cool:

man i was telling my mechanic about your car Dan, they don't believe me one bit. Saying that it was, "Impossible" and that i was full of it.

Some people just don't believe enough.

Two months ago I wouldn't have believed it, either. You really have to see the numbers on your own gas receipt before fully realizing how much room for improvement exists.

I believe it or Honda would not do the Belly Pan thing to their Hybrids that they do. Not to mention the {Beautiful-Wheels} they use to cut wind resistance.

Its hard for me to believe also. I won the car on ebay and before going to pick it up I was hoping for 45MPG. After driving a week I was hoping for 50. Now I am aiminf gor 70. A few more mods and I might just be able to do it in the summer.

Hi Dan:

___Although I can see the mods giving you maybe 5 mpg, it is still “you” behind the windscreen and you are still just wringing her out. I cannot wait to hear of your first 70 mpg tank! Congrats on the first segment at that level! Next will be a string of segments and then a tank after that ;) Sooner then later I suspect!

___Good Luck

___Wayne

Looks great, but I worry about it all catching fire since it is plastic.
How many miles have you put on the car since the mods ?
After a long trip, how hot does the underneath side get under the engine ?
I also worry about trapped heat near the fuel tank .

Your thoughts ....

Looks great, but I worry about it all catching fire since it is plastic.
How many miles have you put on the car since the mods ?
After a long trip, how hot does the underneath side get under the engine ?
I also worry about trapped heat near the fuel tank .

Your thoughts ....

In recent months I have sold the Del Sol and bought a Civic HB VX. I installed the same belly pan and added to it to completely seal the exhaust system except for the tailpipe. The coroplast has 1/2 clearance around the muffler. I have been driving a lot lately and have 7k miles on it since I installed it. I'm not aware of any fires yet.

Proceed at your own risk.
:eek:

Aren't you worried about getting a leak in the exhaust system and not having anywhere for the co to go but inside the cabin?

Please post some pictures of your bellypan ! ( The more the better ! )

We have the same car - mine is a DX auto though.

BTW, Honda included a small piece of plastic under the backsides of all VX models for better aero. I have never seen one of these pieces before, and have gone so far as to "accidently" drop something near a Civic VX so that I could see one of these.
Still no luck.
Any chance you could post a pic of the backside of your car before the mods so I could see what one of these things looks like ?

Aren't you worried about getting a leak in the exhaust system and not having anywhere for the co to go but inside the cabin?

I have a brand spankin new exhaust system so I;m not worried.

Actually, that will never be a problem because there is air flowing from the grille thru the exhaust tunnel and it exits around the muffler. There are also areas to exit at the rear wheelwells. It is not really completely sealed.:p

Please post some pictures of your bellypan ! ( The more the better ! )

We have the same car - mine is a DX auto though.

BTW, Honda included a small piece of plastic under the backsides of all VX models for better aero. I have never seen one of these pieces before, and have gone so far as to "accidently" drop something near a Civic VX so that I could see one of these.
Still no luck.
Any chance you could post a pic of the backside of your car before the mods so I could see what one of these things looks like ?


I took pictures but I cant figure out what I did with them. I will have to track them down. The piece that you are talking about on the VX is called a diffuser. It is just a hollow block of plastic that fits behind the drivers side rear wheelwell and the rear bumper cover. It just prevents air from getting hung up in the bumper cover. It is only on the drivers side because the muffler is in the way on the passenger side. I will try to remember to do it later as I am traveling without a camera.