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

[Greg Hermann]

>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

Plus you will avoid the compressor work (and volume capacity) involved in
compressing the evaporated portion of the H2O.

Greg