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

[Theodore Chen]

--- Paul Friedenberg <paulunm at msn.com> wrote:
>
> I am not at all concerned with the rubber lines, their rating far exceeds
> any pressure that the oil system would produce, even a cold start. Audi used
> steel braided lines because they could, and they (the Germans) love to
> overengineer everything. Rubber oil lines have been used for years
> successfully by many manufacturers and individuals. Besides, the most
> compelling arguement for rubber lines is-- You guessed it, Hap uses
> rubber(lines that is)!

it's clear that you've gotten emotionally attached to your setup, but
for the benefit of others who might be tempted to do something similar,
i'll suggest some bedtime reading in the form of carroll smith's books.

in just about every book he's written, carroll smith says he would
never use rubber hoses on a race car.  what do you think he would say to
hose clamps?  reinforced rubber hoses might be ok for a while, but a
few years of exposure to harsh environmental conditions can change things
in a hurry.

braided stainless steel hoses aren't much more, and they're more reliable.
how much will it cost you to rebuild the engine if you spin a bearing?
how much will it cost you to repair the car if you spin in your own oil
and stuff the car?

over the years, i've seen a number of cars come off the track with blown
oil lines, almost always rubber (but sometimes improperly installed
braided steel hose).  some of them were rubber with hose clamps, just
like yours.  they failed right at the hose clamp junction, since that is
the point of highest stress due to the compression of the clamp.

while i'm at it, i'll point out that you should revise the mounting of
the oil cooler.  one problem is that you used the tabs on the cooler
for mounting it.  that's going to subject it to a lot of vibration, so
at the very least, you should sandwich a layer of neoprene rubber between
the tab and the bracket on the chassis.  tabs like those have been known
to break, however, so i would rather mount the cooler using a channel
or fingers lined with rubber.  carroll smith specifically recommends
against using the tabs for mounting.

the next issue is the orientation of the cooler.  it would be more
effective if you turned it 180 degrees, so that oil enters and exits from
the top instead of from the bottom.  when the oil enters and exits from
the bottom, it will tend to take the path of least resistance, which
would be the rows at the bottom.  turning it so that the oil enters
and exits from the top will cause the oil to more fully circulate
throughout the cooler.  another one of carroll smith's recommendations.

this isn't to say that your setup is guaranteed to fail.  it may or it
may not.  but the changes people are suggesting will reduce the chances of
a failure (potentially catastrophic).  i don't believe audi engineers used
braided steel lines just because they could, but because they wanted to
make sure the lines didn't pop even after a few years.  how lucky do
you feel?

> The temps that I see on a hot day, at high speeds, is comprable to what you
> would see with a normal oil cooler on a winter day, at non highway speeds,
> ie the first tick mark, for lack of better terms. I cannot give you a number
> for this value.

did the later S4/S6 drop the numbers?  my '92 has numbers on the gauge -
not at every tick mark, but the first tick is marked as 60.  the manual
indicates that the next one is 100.

not trying to criticize, but i've seen plenty of people get so proud
of their setups that they don't want to know about the things that might
be wrong with it, only to come into the pits with their tails between
their legs after their setups fail.  if they were lucky, all they did
was oil down the track, requiring the track to be shut down for 20 minutes
so the cornerworkers can spread oil-dri all over the place.  and if
they weren't lucky, they spun in their own oil and had to bring
their cars home in a baggie.

the first rule of doing home-grown modifications on your car is never
get attached to any particular design.  you should be looking at it
critically and asking yourself, "how's this thing gonna break?"  that's
why i strongly recommend carroll smith's books.  he's had many years
of experience, and broken many parts in the process of figuring out
what works.  that's why i listen to people like scott j., who's worked
on more audis and race cars than i can shake a stick at.  i might not
always agree with him, but i listen.  perhaps you should do the same,
instead of getting defensive about your setup.

but hey, it's your car.

-teddy


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