One of the features of ACE is that one of the PBOs has the feature that it lets spent ammo stay around longer. The tank shells in my mod have the shell whistle sound "attached" to them, so if another mod makes the shells stay longer than usual the spent shells hang in the air over the tank wreck and whislte until the code tells them to dissappear. In the stock game the spent ammo dissapears straight away and so is not a problem.

What you can do to enjoy both worlds is to turn off "ammo stays" by either changing the ACE game settings or removing the COOKOFF.PBO from the ACE folder. Or not using ACE.