I remember some time ago, there were links to trailers with winglets
on their rear side/top surfaces. Somewhat like what the "new" mitsu
evo-9 has on the trailing edge of its roof.

On 7/29/07, mathew Bennett <matsuwesty@earthlink.net> wrote:
> I have been reading the info about van aerodynamics with great interest, as
> I have been doing some brainstorming of my own in this regard.  The idea of
> an under body pan under the engine is intriguing.  Also, the idea of
> rounding the rear of the van has been something I've thought about and the
> best idea I can some up with that won't look odd and will provide some
> manner of practical use would be a trailer.  The trailer can have a rounded
> rear, it can be as long as you want it to be, it can be removed when you
> don't need it, and you can even attach a "bellows" between the trailer and
> the rear of the van to not allow air to become trapped between the van and
> the trailer.  It won't help our rear vision issue, but you could use a lower
> trailer that would allow some rear vision (with no bellows) and make it long
> enough to allow the air flow to smooth out off the back of the van.  I have
> a tandem kayak on the roof-rack of my Westy frequently and when it's
> inverted with most of the kayak off the back of the van (compared to the
> front), it makes the van much more stable in crosswinds and my gas mileage
> increases by about 1-2 mpg.  It is acting like the tail of an airplane to
> stabilize the van and it also allows the air over the roof to smoothly go
> over the roof instead of creating turbulence.
> Regarding high-output alternators: make sure you find out what the rpm range
> (of your motor, not the alternator) is for charging.  Many of these
> high-output alternators will put out tons of amps at higher rpms, but when
> you are idling they actually discharge your battery.  Also, many of these
> high-output alternators can damage your electronics in your vehicle.  They
> can come on with a large current pulse that will damage ECU's, radios,
> relays, etc, they can actually create more problems than they fix.  Many do
> not have "ramp-style" voltage regulators that will protect your electronics.
>  By ramp-style, I mean that the alternator output comes on gradually, not
> suddenly.  It's generally less than a second, but enough time to allow your
> sensitive electronics to take the increase in input and not be fried by a
> large pulse of energy.
> Just my 4 cents (adjusted inflation),
>
> Matt
>
>
> Matsuwesty Adventures website: http://home.earthlink.net/~matsuwesty
> FAVOR website: http://home.earthlink.net/~clubvanagon
> Yahoo FAVOR website: http://autos.groups.yahoo.com/group/vanagon_club
>