Rodney,
It's not as complicated as all that. Just follow the requirements in
your owner's manual, and change it regularly. All other things being
equal, lighter weight oils have lower frictional losses, but may
provide less lubrication at high temperatures (synthetics excepted).
With the higher oil temps a turbo motor sees, synthetic can offer an
extra margin of safety. That's because it has a higher "flash point"
(temperature at which the oil bursts into flame in open air), so it
can withstand higher temps than dino juice before turning into coal
slurry. Synthetics generally have higher film strength as well
(that's the amount of pressure a thin film of oil between metal plates
can stand before shearing). That will matter when, as Mike Lowe puts
it, you come off a corner one gear too high and decide to test your
engine bearings by mashing the throttle anyway.
There are proven benefits to synthetic *oil*, but I have yet to see
data for synthetic *filters*, so I'm sticking with the basic paper
filters. Unlike the case with oil, the OEM filter from some companies
like Ford and Mazda is much better quality than the aftermarket stuff.
Aftermarket, I would happily use NAPA Gold or Wix, and stay the
_hell_ away from Fram.
hth,
Craig Blome
TSSCC, TAMSCC, RTRT, and TLS#91 (I always thought it was obnoxious
listing all your titles... :)
---"H. Rodney Spear" <hrspear@coastalnet.com> wrote:
>
> I've got a new Audi 4 cylinder turbo (the turbo is oil cooled) with
4,600
> miles on it. I live in eastern NC (relatively mild year round). I
plan
> on running several autocrosses/schools each year. What oil and
weight
> would you recomend. I was planning on Mobil 1 15W50, but am now
> considering Redline as well. Redline recommends 10W30 or 10W40 for
> street and occasional track use. They discourage use of their 15W50
or
> 20W50 in cars whose oil temps are regularly below 225 F. I have yet
to
> see my oil temp guage over 200 F. Also, should I go with a
synthetic oil
> filter? TIA.
>
> Regards,
> Rodney
>
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