that pipe is for you are pump/smog it lets the excess air in to the exhaust to help with poulition control you need it connected if you have emissions in your state it will lower the poulition gases when they stick that rod in the tail pipe it will help you but if you dont connect it you may not pass. there are no hanger brakets on cats they are held up by the exhaut pipe so if you straight pipe it i recomend to well that piece in. if you look at your air pump on the top there is a valve that goes into a large rubber hose then into a pipe that goes right over the header that leads down to the cat

 

i forgot who said it but someone said that taking off the cat wont do anything or be worth it...... sorry but that is a load of bull. i have a 1994 dakota with the 3.9 in it and when i took the cat off it woke it up big time, if i drive the truck rite i can get 30mpg!! i got about 10mpg just by taking the cat off. it sounds much better, i used to have a cherry bomb on it and it sounded awesome , then i upgraded to a flowmaster super 44 and it sounds even better... if u can get away with it off GO FOR IT!!

 

Your 3.9 doesn't get 30MPG and you didn't gain 10MPG by removing the cat. You are higher than a kite my friend.

 

How does a glass pack or cherry bonb even sound on a 3.9, i personaly thought and was told that since its only a 6 cylindered engine it would sound like crap
and are flowmasters for performance or just give good or loud sound

 

IMO glasspacks usually don't sound good on anything. Flowmasters will outperform factory mufflers but still flow less than many other mufflers out there, I noticed the difference between my 40 series and Aero Turbine, and the AT sounds better too.

 

+1 to what Hahns said. The only way your truck got 30 mpg is if you were going downhill with the wind and the truck in neutral. I doubt the 2.5L 4 cyl dakota can even pull off 30.

 

the glass pack sounds ok when idleing but it sounds like crap when reved and i was told that the 2 1/4 exhaust was to small for my v6 is that true as well?

 

if any one wants a update i decided to remove the cat completly i put ona off brand flowmaster on dualed it out in front of both tires with 3 inch stainless steel tips it sounds almost like a v8