https://www.dieselplace.com/forum/63...roject-12.html
Gonna leave this here. PrivatePilot added Water Injection to his 97, and it saw a 1 to 2 MPG benefit. He was only using tap water, there might be more benefit if you use a Water and Methanol Mix. I don't know all of the details, supposedly the 6.5 has detonation issues if you use much methanol and that'll destroy the engine?