engine/turbo theory question

[JShadzi at aol.com]

In a message dated 10/17/00 5:00:49 AM Pacific Daylight Time, 
kris_j_hansen at yahoo.com writes:

<< Well, that sounds great, but what will create the
 hydraulic pressure to drive the turbo? A pump? Won't
 the hydraulyic pump drag on the engine more than a
 little turbo in the exhaust? Kind of like a
 supercharger?
  >>

    Yes, there is no such thing as free power.  It takes energy to make 
energy, there is always a trade off.  What most super/turbo charger 
manufacturers are attempting to do is create boost more efficiently, with 
lower lag and lower intake charge temps.  
    There are also other considerations too, for example an exh. driven turbo 
charger is a sink for much of the heat energy in the exh. gas, thus reducing 
the effectiveness of the catalytic converter during warm up.  A pump driven 
turbo would not contribute to this, thus being more smog friendly.  This is 
also why we may all see the demise of the exh. driven turbo in the near 
future.  Manufacturers are scrambling to build the next best thing.
Javad