muffler inlet & through hole size..

[wildboar]

ok lets say a muffler has got a 2.5" inlet...should the diameter of the hole flowing through the muffler box be also 2.5"?? ive seen many mufflers wif supposedly 2.5" inlet but when i look from the outlet (inlet got piping connected so cannot see into the hole), i notice that the hole is smaller...is this normal?? or should the size be 2.5" all the way fr inlet right thru the muffler box till the outlet hole (not the muffler tip)...

hope u guys understand wat im talkin abt...

 

[taqu]

The cheaper mufflers are usually like that. I don't if they're scientfical reasons for that. I guess consistent size all the ways is better.