Hi Doax,
Here's a link to the generic 'water injection' for fuel saving:
Snow Performance : Diesel MPG-MAX
There is a little deiesel stuff on the aquamist forum, but if you read that forum you will get the idea:
waterinjection.info - Powered by vBulletin
THIS is the main link that will help you though:
CHEMICAL COOLING « Killerbee Performance Technologies
Once you know a bit, I'll be happy to field questions.
PS - Aquamist know what they are doing. They setup the WI system on the land speed record diesel:
http://www.aquamist.co.uk/dieselmax/