re: coking in turbo bushing

[gfl@cc.bellcore.com (grant f lenahan)]

Yes, a good synthetic will reduce coking-caused failure.
If you look at the _great_ posting by Ed Hackett, he
compares the "flash point" of many oild, including 
Mobil1 and Amsoil.  They have flash points which are MUCH
higher than the dino oils.

Just as a supporting observation, some oils are
rated for turbos, and carry a "turbo approved"
label.  These also have a hgiher flash point,
and a better viscosity index.  No 10-40 oils,
for example, qualify, but many 10-30w (with
better VIs), do.

If you don;t agree, take a low stability oil
and fry it hard on your stove.  Then take peanut oil
or another higher stability (higher heat) oil and do
the same.  Which resisdual do you want in your tight
turbo bushing?

Calloway always specified synthetic or turbo approved
oils for its VW/audi turbo kits, BTW.

Grant