Turbo Care - It's Red Hot!

[scott.john.mockry@bangate1.tek.com]

Regarding the recent discussions around extending  your turbo life.....

My favorite  SAE article #860103 has a nice graph showing the difference 
in temperatures after engine shut down over a 10 minute period for the 
turbo
impeller bearing and the impeller shaft sealing rings  (similar to metal 
piston rings) 
on the early  "oil cooled" turbo versus the 1986> "water cooled" turbos.

After engine shutoff on the "oil cooled" turbo within two minutes the 
impeller shaft sealing
ring temperature rises from 260 degrees C  to around 375  degrees C.
The oil cooled turbo shaft  bearing goes from 140 degrees C up to around 
250 degrees C. 

After shut down on the watercooled turbo the shaft sealing rings go from
190 degrees C  "down" to around 170 degrees C in less than  a minute.
 the turbo shaft bearing goes from 125 degrees up to around 
140 degrees C and then gradually tapers off back to 120 degrees over the
next 8 -10 minutes.

Even after 10 minutes the oil cooled turbos sealing rings are still
at 280 degrees C and the bearing is at 240 degrees C.

If you ever need a reminder to take  your turbo charged Audi engine
through a "cool down phase" after doing a hard run under boost, open 
your hood during the evening with no ambient light around and see
the red hot "glow in the dark" exhaust manifold and turbo housing.
Even on the water cooled turbos it will get your attention right now!

Scott M.