well I have been messing about with .wav files trying to get my engine to sound different then the normal chatter it puts out all of the time. I have been trying to replace
Submarine_diesel_underwater.wav
Submarine_diesel_exterior.wav
in the data\sound\ folder
I recorded/mixed new mono sounds at same bitrate as the original file and tried to make it about the same length as the orginal .wav's (I don't think I got the length right on, and this might have something to do with it)
But when I replace the old files I get no engine noise at all.

Anybody have any clue as to what I am doing wrong? anyone have success doing this kind of thing before?