This mod is Cummins N14 Celect Plus engine with straight pipe sound Version 1.0 Feature: Cummins N14 Celect Plus 435-525HP and 600HP tuned with staright pipe sound Realistic turbo behavior when start, stop, no throttle, jake brake and blow off valve engage Custom sound attenuation for realistic sound fade off Custom sound orientation for realistic sound from different angle Custom sound distortion for realistic exhaust tone depends on how much throttle pressed