I too experimented with dry ice and found out what Brian has in his other post. I didn't have any datalogging software or a thermometer and I had 3x the volume of liquid. The water was cool to the touch, but once the car was running it warmed up fast. Here's the video of the old setup, it was ghetto, but it was cheap and allowed me to experiment. http://www.youtube.com/watch?v=lefNz407oeg
And as Brian stated the dry ice makes some serious smoke, which makes people wonder WTF? I started working on a new/cleaner setup this weekend. Looks like this so far.