Date:         Sun, 19 May 2002 14:45:34 EDT
Reply-To:     FrankGRUN@AOL.COM
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Frank Grunthaner <FrankGRUN@AOL.COM>
Subject:      Re: Addition engine cooling thoughts/ Oil Cooler Issues
Content-Type: text/plain; charset="US-ASCII"

In a message dated 5/13/02 10:34:27 PM, vanagon@VOLKSWAGEN.ORG writes:

<< The water-oil "cooler" is more of a oil temp moderator than cooler!
Sustained high speed driving is where I see my oil temps rise. The lower
Tstat helps to some degree, but as you suspect, an external oil cooler would
be the answer. Both Frank Grunthaler (I4) and Stan Wilder (air-cooled) have
installed a RX-7 oil cooler. They  have found that solution to work.

### Anyone have the dimensions of these coolers???

> My idea is to do the following to keep the temps down to a minimum in the
> engine.  First, mount an 12'x4' oil cooler on the right side of the engine
> bay where there is all sorts of room below the coolant bottle - protect it
 >>

Dave,

I meant to get back to you on the oil cooler questions but it has been rather
hectic here. Besides, reading your previous post in the North American
Standard English Format, I was stunned at you desire/plan to mount a 12 foot
by 4 foot oil cooler sail on top of the Vanagon. Really more surface area
than needed!!

The RX-7 cooler is a superb unit. The size is 23 inches x 5.25 inches x 2
inches thick. It has a built-in thermostatic bypass and a pressure drop of
less than 2 psi hot. It drops my oil temperatures by 45 F on the average
without cooling fans. I mounted a bank of 5 12V muffin tin fans in a puller
configuration on the cooler and mounted it to the body above the
transmission. I was going to mount it between the frame rails, but didn't
like angle I would need. I did add Aluminum ducting to add more air to the
region, but before and after testing showed no significant gains, so it was
removed. To access the oil I used a generic sandwich adapter without
thermostat. I also added a remote oil filter at the time mounting a huge
filter in a vertical configuration.

However, with the Audi 3A Turbo project, I have taken a different tack. I
have acquired the oil filter adapter flange from the early Audi 5000T,
complete with its dual oil filter casting (actually, I've got about 5 of the
single units as well). As you may know, this filter mount includes
connections to an external oil cooler and has an internal thermostatic
bypass. The unit mounts cleanly on the oil filter mount from an Audi 4000S or
Fox (angled to the rear). With a few modifications, this double oil filter
unit fits cleanly on the 3A block. I have fitted the original oil-to-water
cooler/heater to the oil flange as well. The dual oil filters clear the A/C
lines, water lines, etc. The unit has takeoffs for the turbo oil supply, and
all the gauges one could desire.

As for the external oil coolers, (as I have recounted here before), I am
mounting two of them (the original Audi 5000T stock external coolers) behind
the rear wheel, passenger side. I have cut an opening behind the taillight,
placed a heavy steel grill to support my auxiliary battery and added an 8
inch diameter radiator fan from a Ford Festiva in a pusher configuration
between the plenum air source and the oil coolers. The package is enclosed in
an Aluminum sheet duct which encloses the coolers and fan, blocks any water
or road spray from the tires and opens to the rear. The net air flow is then
from the passenger side rear air scoop, down to cool the batteries, through
the oil coolers and out parallel to the road and directly to rear. I measure
between 2 and 5 inches of water negative pressure at this point as a function
of vehicle speed. The fan is triggered thermostatically from the engine oil
temperature. One of the oil coolers is plumbed directly to Audi 5000T oil
flange. The other takes oil from the scavenger pump evacuating my auxiliary
oil sump (taking oil from the turbo) cooling it before reintroduction of the
oil to the crankcase. A mirror image of the air flow system is used on the
driver's side to mount the SAAB air-to-air intercooler. Here, I use the
chamber behind the driver's side to mount the air cleaner assembly and the
same model electric fan is used to push air through the intercooler. As a
result, neither of the rear air scoops inject air into the engine compa
rtment.

Oh well, hoped someone would be interested.

Frank Grunthaner