Are they basically the same thing? I had an extra 2.5" catco cat that I hollowed and upon doing so it isnt exactly a 'straight' pipe since the heatshields flare around and make an oval into the outlet. I may decide to use this 'hollow' cat, but would a straight pipe be better (if so)? Thanks.

 

i have heard that you should run a straight pipe vs. a gutted cat, due to resonation of the gutted cat impeding exhaust flow. something to the extent that the big hollow opening of the cat is not conductive to exhaust flow vs a straight shot with the test pipe. i never dynoed back to back, so it is all heresay.

 

evil polluter you! No J/K , but the above statement is correct.

 

[Modified by joy-Ride, 6:51 PM 7/13/2002]

 

I tried gutted stock cat.
I tried testpipe
I am running 2.5 gutted cat now..
Testpipe performs better than gutted cat or highflow cat.

 

Im running the testpipe now as well. Very loud and according to the butt dyno more power than the high flow 2.5"