i was wondering how exhausts are measured because the exhaust i was looking at(tanabe ultra) is supposedly 3.175" or so....a little bigger than 3. When i measured the across the inside, the actual width of the inside is only 2.75'' , and the width of the wholeoutside was like 3.1 something. I was guessing when they say 3'' exhaust, that thats the width of the inside of the pipe? If so, i guess the tanabe ultra im looking at is a 2.75'' which would be good for me. Ok right on..

 

anybody/?

 

You measure the inside diameter.

 

you don't measure the exhaust tip. For example, the hks hi power has a 4.5 inch tip, but is really like 2.9 to 3" in piping. Like the other guy said, you measure the pipe's inside diameter.

 

inside diameter.