Considering a removal of your Cummins ISX engine's pollution control system? A “delete,” generally referring to the bypassing of Diesel Particulate Filters (DPFs) and Selective Catalytic Reduction (SCR) https://medium.com/@MatthewArnoldd/diesel-engine-performance-ecm-tuning-and-reliable-equipment-maintenance-9e5d06ef3076?sharedUserId=MatthewArnoldd