I normally drive with a window configuration that has very little buffeting.

On one side of the van only (usually driver's side) open the rear/middle
window 3-4 inches.  Then open the front wing window, and also the front
driver's window about 2-3 inches.  What happens is air blows in the rear
window and out the 2 front windows.  It provides a very nice circulation of
air without any buffeting.  You can experiment with different measures of
openness on those windows to get higher or lower air flow.

Roland

On Wed, May 2, 2012 at 11:46 AM, Steven Shelton <shelton4@gmail.com> wrote:

> A few years ago I bought a rear hatch lock extension bar.  It came in a bag
> with text in German so I didn't know that it wasn't recommended for use
> when driving (making it of very limited usefulness if you have the rear
> screen).  With the extension bar in place while driving with the windows
> open, the air flow through the van was smooth and laminar, far superior to
> the buffeting we get normally. It made driving in in a Georgia summer
> without AC bearable.  I confess that I have occasionally used it while
> driving since discovering that it is not recommended, but exhaust gases
> sometimes leak in.  I would like to come up with a way to achieve this air
> flow without the complication of carbon monoxide poisoning.   Has anyone
> come up with a modification that did this?
>