I was checking out a set of Borla mufflers today ... they were 3" in/out... but when I looked thru the muffler I noticed that the perforated tube inside was considerably smaller then 3"... more like 2.25... is this how Borla makes their mufflers? or are these not really 3" in/out and maybe a muffler shop opened the inlet and outlets to look like they were 3"


anyone who has some, can you take a look and let me know your findings

 

Check to see what the core size is. It is possible for inlet/outlet size to be different then the core.

 

thats what I am asking... I have many other 3" mufflers that all the same inside diameter all the way thru the mufflers... the core does not get smaller inside the muffler case

 

That's what makes borlas so much quieter than other mufflers.