Thats just a resonator, Its a section of pipe that is wider than the rest. Basically it attempts to create a bottle neck at one end, thus making the sound rattle around a little longer making it sound deeper. In theory. However these usually never work like that except on V8s which are already low in the first place.
And if you use that as a solitary muffler you will be extrememly loud.
<span style='font-family:Geneva'><span style='font-size:14pt;line-height:100%'><span style='color:red'>Fox</span></span> <span style='color:gray'>the Pirate</span>
Diplomacy is saying "nice doggy" until you find a rock.</span>
I live my life one quarter mile at a time, and for those 23 or more seconds I'm free.