The ideal would be one large piece of smoothy  shaped fiberglass,
particularily in the middle area.

But sure, anything with mounted metal panels you can fab, .......would be
some improvement, I'll guessitmate 3 % .

Also, front air dam.........to reduce flow under the van - that has
possibilities. 

So would an extensioin off the back of the box shape .
See that pointy thing off the back of an Adventurewagen top.
- that increases direction stability by moving the center of side pressur
aft, so there is an arrow affect .

also, on any box, filling in the flat rear with either body or at least side
and top fairings........helps.
there are racing sailboats whose stern is practically open.......but there
are extentions to the hull 2 or 3 feet long. 

and the smooth overall shape, 0f the Adveturewagon roof is  is CONSIDERABL
better in terms of roof drag than a westy.
The westy roof and front roof rack sucks, big time in terms or turbulence
and drag.  ( I have an AW , not ready yet, FS btw - darn clean no dents no
rust 85 ) 
I have faired over my 85 wolfsburg weekender roof rack - faired it over
smooth.
.5 % improvement maybe.
I have a whole plan for fiberglass westy aero roof system.

But yes, smoothing the bottom of Vanagon could have a small affect.
Going   75, unless downhill, or with a strong tailwind,
Is just burning up fuel unessarily, and very rough on the vanagon.

I figured it out - the whole concept was conceived in the late 70's.
The national speed limit at the time had been 55 mph.
The first 3 years of vanagons had that flagged on their speedo.

So really.........it is a 60 to 65 mph sporty, not quite truck, van.
Damn good vehicle overall.........but 75 cruiser - they ain't Baby ! 

Scott
www.turbovans.com 

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Chris S
Sent: Friday, May 16, 2008 6:02 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Belly Pans for speed or MPG

Has anyone ever fitted full belly pans under their Vanagon for increased
aerodynamic efficiency?  There's a lot under there that snags airflow and
causes unnecessary drag.  I'm contemplating installing galvanized sheets
under the van and some in front.  With 82hp every bit helps while going 75
mph.

Here are pics of the underside to help visualize:

http://i16.photobucket.com/albums/b7/misterpolak/Hershey/25.jpg
http://i16.photobucket.com/albums/b7/misterpolak/Hershey/26.jpg

Any engineering thoughts?  How would you do it?

Chris S.

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