Considering a elimination of your Cummins ISX engine's pollution control system? A “delete,” typically referring to the bypassing of Diesel Particulate Filters (DPFs) and Selective Catalytic Reduction (SCR) https://medium.com/@shine.santhosh61/heavy-duty-diesel-engine-performance-ecm-diagnostics-remote-tuning-and-engine-specific-solutions-f72d130268cc