[s-cars] Oil Cooler Pics posted...

[QSHIPQ at aol.com]

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Ok, saw the pix, I'll put in my .02.
That sure appears to be a standard issue 19row oil cooler listed in the pic
(I gots the same one in my 83 urq), you can use it for a variety of fluids,
including water..  A couple of suggestions.  First, mounting it upside down
creates a potential problem.  Oil drain back into the pan will occur when hot
and you will have overfilled your oil causing oil leaking at the rear crank
seal.  Checking oil levels is a best guess scenario,  actual level will
depend on a couple things, but you can observe anything from +.5 to -.5 quart
depending - neither is a good thing.  ALL audi turbos since 1983 have a 100c
oil thermostat from the factory.  I'd highly suggest using rubber isolators
for the mounting, rigid mounts tend to cause the tank braizing to crack,
causing leaks.  VW and audis are infamous for high oil pressure on startup.
150psi+ is quite often seen, btmt.  Rubber hose clamp connections should be
replaced with something more substantial, you can get a good race shop to
adapt your stock lines to fittings on the cooler (assuming they are -10AN
fittings, which is what you should be using on the audi oil lines - not -8 or
-12).  IMO, the 19 row is equivelent to the stock oil cooler with good
ducting, a bit more if you mount it well (better surface area vs depth),
btmt.  A 25 row is a better choice for the audi turbos IME.  A 25 row will
fit behind a stock S4/S6 bumper with very slight trimming of the inside
bumper trim, btdt.  Assuming this cooler to be hooked to the stock oil line
ports on the oil bracket, one should see 100c, the size of the cooler will
dictate how far above that mark the car will go under extreme use.  Don't
trust ANY audi guage to give you actual readings of anything.  Here a quick
zap with the IR gun is a better measure of what's happening and a quick way
to "calibrate" that audi guage, and to measure temp drop across the face.
Over the years, I've measured dozens of audi turbo oil temps, here's my
summary wrt them.  With 19row OC and good ducting, you should see temps
averaging around 10-15c lower than the stocker, with  a 25 row, you should
see temps averaging in the 20-30 temp drops (all else being equal), which
means the 25 row pretty much sits at 100c for 90% of it's life.  On really
hot track day 90 degrees at Blackhawk full RS2 battle gear, I've seen 25 row
peak at 120 or so.  What you do observe is 100C temps before you get to the
paddock, something the stocker doesn't seem able to do.  I completely agree
with Teddy that oil should get to 100c, anything lower and you aren't
vaporizing the moisture out of the oil, offsetting the oil cooler gains with
a water infested recipe.

My own suggestion is that the stocker vs the 19row is a wash.  Bob Dupree
actually put a "track scoop" on the stocker, and sealed it well.  This
resulted in oil temp drops similar to the 19row application in my 83 urq.


HTH

Scott Justusson
QSHIPQ Perfromance Tuning
Oil coolers aplenty

In a message dated 11/13/02 7:33:08 PM Central Standard Time,
tedebearp at yahoo.com writes:


--- Paul Friedenberg <paulunm at msn.com> wrote:
> Darin, Thanks for posting, you are a great asset to us website retards.
>
> Guys,
>
> The oil cooler is a unit that was supposed to be used with a liquid to air
> intercooler system for a mustang (can't remember the brand, procharger
> maybe?) it was meant for water, but works better for oil. It is similar to
a
> motorcycle radiator. I had rubber lines fabricated to bolt up to the motor,
> and they are hose clamped at the cooler. I am having some oil seepage, but
I
> think that's an easy fix. The cooler itself is mounted to the frame rail
> with some hand made aluminum brackets. My oil stayed fairly cool before, I
> once saw 130 on a 95 ish day, up a steep grade at sustained 100mph+. Now
the
> oil never goes above the first tic mark, even at high speeds in 90-100
> degree weather.

paul,

i'm not quite sure what you're saying, but this thing looks like an oil
cooler to me.  they probably took it and used it for water.  i definitely
wouldn't want to take a heat exchanger designed for water and use it in
an oiling system without doing some checking first.

the viscosities of oil and water are different.  i don't know if you
can take a heat exchanger meant for water and use it for oil.  it
depends on the particular heat exchanger.  another issue is whether
the heat exchanger is designed to withstand the higher pressures seen
in an oiling system.  the cooling system doesn't see much more than
16-24 psi.  the oiling system, on the other hand, sees 30 psi (2 bar)
at idle when warm and 90 psi (6 bar) above idle.  i'm sure the pressure
spikes higher than that when you start the engine.  radiators aren't
built to withstand those kinds of pressures.  even if it holds together
the first few times, that's no guarantee that it won't blow up the 100th
time you start the engine.

i'd also be concerned about the rubber lines and hose clamps.  oil is
the lifeblood of your engine, and rubber hoses have been known to blow
up with pressure spikes.  i'd much rather use braided stainless steel
hose with screw-in fittings, such as AN fittings or NPT fittings.

and if you blow it up at speed, you could wind up oiling your tires
and stuffing the car into a wall.

so what temperatures are you seeing for the oil?  oil should be around
220-240 degrees F.  if you're not going above the first tick mark,
which is 60 degrees C or 140 degrees F, the oil isn't hot enough.
i would install a thermostat if that's the case.

-teddy