Date:         Wed, 15 Dec 1999 23:29:05 -0400
Reply-To:     Paul Schiemer <schiemer@MAGICNET.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Paul Schiemer <schiemer@MAGICNET.NET>
Subject:      Re: Air Scoops
Content-type: text/plain; charset="ISO-8859-1"

Cool incoming air comes down the flue (for lack of a better word) on both
sides at the rear of the van. It comes into the engine bay by way of the two
cubical openings on either side, and right across the engine.
The squirrel fan redirects the air through the vented tin channels around
the hottest part of the engine, the cylinders. Some of that air is directed
into the heating ducts, but is usually blocked off from moving forward via
the vents at the heater boxes around the "J" tubes.
Some of the air is used by the carb or air intake to mix with fuel and be
ignited in the compressed confine of the cylinders.
Cooling air exits the engine compartment through openings between the body,
the tin, and through the gaps provided by lousy fit (just had to say that).
It's not the most efficient design, but it wasn't intended to be either.
It is functional, clear and simple.

Temps in the engine compartment can reach 220°+ F under loads and highway
conditions. That's darn hot for any vehicle. Probably the greatest damage
occurs to the engine immediately after it is shut off. A better way to
utilize the exterior vents might be to add rheostat controlled fans up there
to continue moving cool air into the engine compartment for a few minutes
after being shut down. <---now there's a novel concept!

While the engine is a pump it produces an interesting byproduct from the
super heated air and combustion cycle- sulfuric acid. Ever wonder why
mufflers rust out so quickly?
At the same time, if you cool the pump too much while in use it can't 'burn
off' the acid solids (normally vaporized at the point of combustion).
A delicate balance.
But dropping the operating temp on a Vanagon by twenty to thirty degrees
can't hurt anything. Ideally it would run around 180° F.