[torsen] Re: [urq] Water Cooled Turbos - should be water jacketed turbos

QSHIPQ at aol.com QSHIPQ at aol.com
Wed Feb 14 10:03:15 EST 2001

In a message dated 2/14/01 7:38:41 AM Central Standard Time, 
Ur-quattro at msn.com writes:

> Scott,
>  Please help me to understand how a WJ turbo extracts heat from piston 
>  post-shutdown.
>  TIA,
>   - Doug

A couple of things doug, Post shutdown, the temps are lower to start with 
-1>0min.  So post shutdown the rings are cooler  (in 860103 piston ring temp 
is 260C at 0t, with WJ the pisdont ring temp is 190 at 0t).  Post shutdown the peak 
is 375C without the water Jacket, 190 with the jacket.  So, post shutdown, 
the piston ring temps are not really influenced by water recirculation, the 
help is before water recirc.  If one looks at 880258 (The development of a 
Severe Turbocharger Bench test) you can see that it's sump temps that are 
*really* high without the water jacketing, like in the 150C range (indicating 
high piston ring temps due to viscocity breakdown of oil).  This also leads 
to heat soaking across the center bearing, and all this leads to higher 
combustion temps.

I encourage anyone that really wants to look at what's happening in your 
turbocharged car, to get some of the SAE articles, many printed.  And, unlike 
the single manufacturer t*rsen papers leading to a lot of self promotion, 
just about all the production turbo players are represented, so are many oil 
manufacturers.  The late 80's papers on turbos are pretty scarey in terms of 
what's been happening in your turbo motor up until the WJ turbo.


Scott Justusson

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