Then again, the smoke might thrust it in an upward motion, causing it to dissolve in the extreme heat? I got an idea...
...the Pipes aren't as thick as they really are, right? So maybe that extra empty part of the tube collects water, and doesn't disturb the thrusting motion let out by the smoke. Eventually, the pipes will heat up, and they will naturally dry off, without distrubing the natural flow of the exaust, leaving that signature sound there 24/7. Just a thought.