Whats a safe EGT for our engines?

[AudiVWguy]

Bugnut, I understand the cooling effect of the last water injector. How does injecting pre-turbo increase the turbo's efficiency? I would think that anything other than air wouldn't not be good for the turbo blades spinning that fast. Please explain?
Cheers,
-JB

[bugnut]

 Some people do worry about compressor erosion.  Just got to make sure the water droplet size is small like a fog.  10 micron range.  In a nutshell the cooler you can get the air the more efficient the turbo can be.  And if you can do this before the compressor you are way ahead of the game. Now when I say before I mean the heat is removed before it builds up.   I have read that some people can get the temps so low that intercooler is not used.  If one was to be used then that would actually heat up the charge.  If this is true or not who knows.  I did most of my reading on this pre-turbo over at the aquamist web site.  There are a couple of stickys on it in the gasoline forum.