https://industrialpowerup.com/....product/cummins-def-
Deleting the emissions system on a Cummins X15 engine—commonly called a “delete”—involves removing components like the DPF, EGR, and SCR. While some claim improved fuel efficiency and performance, it's illegal under EPA regulations and can void warranties, reduce resale value, and harm the environment. Owners should weigh the risks carefully and consider legal performance upgrades instead. Always consult a certified diesel mechanic before making modifications.