---Dick Rasmussen <rasmussend@mindspring.com> wrote:
>
> In any case, letting
> the engine run (depending on what the owner's manual says) after
getting
> the car hot is a common approach to cooling the turbo oil back down to
> normal operating temp. It gives the turbo and oil a chance to cool
back down.
>
What's happening here is that the turbine, which spins at
80,000-120,000 rpm, takes a little time to spin down. Leaving the
engine running continues to circulate oil to dissipate the heat this
makes. An auxiliary oil pump like the "Turbo Luber" or the factory
stuff Porsche used on some cars serves the same purpose.
> expensive oils, such as Redline, is if you don't change it as often
as you
> would a more affordable oil, you lose some of the benefits.
I talked to a Mobil 1 rep about this once, and he said that in
practice you can safely double the maximum recommended factory change
interval (works out to 15,000 miles for my car), so long as you
continue to change the filter every 3K miles. I guess that means it
doesn't lose its lubricity as fast as mineral oil, but you still need
fresh filters to continue removing contaminants.
>I would either
> run the genuine Audi filter, or the correct Fram.
Dick, this is the only thing you mention that I _strongly_ disagree
with. I wouldn't use a Fram filter on a bet. I've heard too many
horror stories about their QC, and they seem to play fast and loose
with filter specs. (Example: The Fram filter listed for a Taurus SHO
uses a relief spring that puts the filter in full bypass at the
engine's normal oil pressure! I switched back to Motorcraft when I
found that little tidbit...) There are motorcycle racetracks that
have banned Fram filters outright, as one model was known to blow off
the engine at speed...(faulty crimp on the filter can)
Cheers,
Craig Blome
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