Steve
in addition to water injection, improving charge air cooling will be directly be reflected by EGT. Using a 2 stage cooling as in air/air with water spray, then thru an ice water cooler will provide charge air temps of less than ambient on the salt. My data was with a gasoline engine, with turbo air flow of 75 pounds per minute,
I don't quite know the failure modes of diesel engines with high EGT's, I would expect melted components like turbine wheels, but Inconnel turbine wheels and exhaust valves were common when I was running the Merkur.
After one failure with a lesser alloy, I switched. With these parts 1900 degrees F could be withstood. The old Roush turbo GTO engines were consistently running 1850 f.
With your water injection, as others have said, you need to provide a way to seal the tank, and have sealed containers of water that they can observe being added. I've never run water injection but coincidently
just read a very old white paper where Ford did some testing in the mid 50's with water injection and how it affects NOx and HC. There findings were that no power improvements at the conditions they were testing.
Interesting that they were looking at these things so long ago. Not surprising though. In the very early 70's I spent several years at research and worked on and witnessed some really interesting programs. I sure learned a bunch.