Mack E9 V8 Straight pipe sound v1.0 1.57

This mod is Mack E9 V8 Straight pipe sound for Harven's R Series, Dielingwu's Superliner, KSW's Superliner, and BPM's MH613 Latest Version Feature: -Mack E9 V8 400-500HP with straight piped sound -2 variants available: electric starter and air starter -Automatically activated engine fan -Exhaust stack simulation effects -Sound attenuation effects for realistic sound fade off from the distance -Sound distortions and directional effects for realistic distortions from different positions around the truck