to use the new engine sound, open the sound.txt file located on your
/sound dir and copy these lines at the end of it:

2158		// Sound ID
0x00,0x01	// Type (0), Flags (0)
69MPS.WAV	// File name
5300		// Priority
1		// Repeat rate
250,400 	// MinVol, MaxVol
0,0		// MinPitch, MaxPitch
0,0		// MinSpeed, MaxSpeed
0x0		// Special FX index
0		// Number of low memory alternatives