there is a pipe that is welded in at 90 degrees after the cat but before the split
what is it for?

 

It's a hemholtz resonator, used for tuning out unpleasant "droning" from the exhaust.

 

after many miles on the freeway with my ap2 i need to call Honda and let them know it didn't work.

 

Get an Invidia or a single exhaust without one and you'll appreciate it being there

 

my ap1 has the same piece

 

mine too. A 2001. I was wondering what it was earlier this week when I was installing my test pipe.

 

All stock S2k exhausts have it.

 

My Triflow exhaust has one but its at 45 degrees

 

Or maybe it does!

Drive Safe,
Steve R.

 

can one.. theoretically sawzall it off.. and weld it onto an aftermarket muffler? i assume 1 can.. but i also assume the resonator is frequency dependent and tuned to the stock exhaust, hence inaffective for aftermarket units...