Cat bypass pipe or hollowed out converter?

[PK 77 911]

I live in Victoria, B.C. Canada
Is there any difference in sound or performance between the two.
I am going to put one or the other on my 84 cab but unsure of the different caracteristics of the two.

Thanks
PK

[Zeke]

AFAIC, by the time the exhaust gases get to the cat, things are out of balance and nothing will make much difference other than less back pressure. An old clogged cat can be problematic in that regard. If your cat is restrictive, either choice will make a little difference.

I'm waiting to see a better aftermarket system for the 3.0-3.2 engines than what I have seen so far that is CA legal. I think dual cats is part of the answer.

You don't say where you are, so I don't know if that makes any difference to you.

[Rick V]

Well gutting the cat is big time trouble if you get cought doing it, no matter where you live. Ok enough of the leagal crap. If you gut the cat you will get a tinny sound, there is too much space for the exhaust to move and bounce around. The Test pipe is a good alternative for sound. I have the Bursch plain old steel test pipe on my SC and I love it. I don't have to have a big name on my stuff, just has to perform well and be made right.
I also matched it up with the Bursch muffler, I like the sound.

[kepperly]

Second on the Bursch, works good and just keep it painted and they will stay PRETTY.
Keith Epperly
87 slant nose turbo look carrera cabriolet

[rnln]

so there is not really performance gain, only sound?

[PK 77 911]

Sound is what I am after. I am not expecting a big performance gain. I have a 77' 2.7L with SSi and 2 in 1 out. It sounds awsome! I would like to get close to that if possible.

Sounds like the pipe is the way to go. There is no emmission testing in BC.

[911nut]

I hollowed out my cat on my old Sc and the car felt like it was tied to a tree.
Go ahead and buy the bypass pipe. They are not very expensive and they do free up the motor a little bit at high rpms.

[rnln]

911nut,
"tie to a tree" meaning it's feel SLOW? How can hollowing the cat make it slower while straight pipe make it faster? umm..