[Fwd: [M] [M} IC Thermodynamics]- Part 3

[Roger Heflin]

On Tue, 3 Nov 1998, Bruce Plecan wrote:

> 
> A more cost efficient use (cheap) is to cool the turbo with water/alcohol
> >>  injection into the turbo inlet. The turbo really atomizes the liquid,
> >>  causing it to evaporate rapidly, absorbing a lot of heat and volume,
> thus
> >>  reducing boost, which the turbo promptly replaces. This is very
> efficient
> >>  for street thrillers that don't need more than 10 seconds worth of WOT.
> >>
> >I went this route several year ago, and had problems with the
> alchohol/water
> >mix having an "abrasive" effect on the compressor wheel.  I would not do it
> >again.  BUT I have never seen pistons so sparking clean at teardown time,
> >as with water injection.
> 
> A SECOND I WOULDN"T DO THAT.    The cetrifical force blows it
> to the walls anyway.  Use lots of pressure downstream of the the turbo.
> Bruce
> 
To add to the comments, I remember being told that if you get your
steam too cold and doplets form it is really really hard on the
turbine, and I would expect the same thing for a turbo.  At the kind
of speeds those things run at water is an effective abrasive.  If you
were going to do water injection put it on the other side of the
compressor before the inlet, the effect should be pretty similar.

				Roger