Ditch the Cat or not ?

[ROGER/DODGER]

I just got a new 2006 duelly 4x4. I think I will trash the muffler, and run the straight pipe like on my 2001, but I don't know if I should leave on the cat or trash the whole works? Any thoughts on this one ?

 

[BTighe]

unless you need it id say toss it. unless you want more restriction.

 

[Coolslice]

I tossed mine. . Well, actually I kept in the garage it after hearing what they cost. :-laf I like it better without it. It sounds, runs, and smells better IMO. However, I live in a state where there is no emissions testing. If I did, I would have left it on. Then again, I have heard some people here say that the truck will pass the actual emissions test w/out it, but not the visual. Not really sure about that stuff as it doesn't really apply to me.

 

[JRD]

I put a resonator inplace of my cat to help keep exhaust drone down. Plus when it comes time to visual inspection, I hope they will think the resonator is a cat. Some of those guys that work at the inspection facilities dont care as long as something is there that might resemble a cat. Also I gained . 2 off my ET after removing my cat with no other mods (not much but its some performance gain). EGT's dropped about 50 degrees cruising down the highway. Not to mention it sounds better and smells more like a diesel than a forklift... But just in case, my cat is still around if I need to install it. Dont throw it away!

 

[JStaib]

I cut the pipe just past the cat and installed a magnaflow 4" in and dual 3" out. While i was down there i peeked into the cat. Sorta clay like material in there. I took an extra long drill bit and drilled into the clay about fifty times till i could take a prybay and break it up. Ran the engine till it all blew out. This way it looks stock and will still pass inspection. Quiet till you hammer on it.

 

[GButia]

I lost my cat and it sounds pretty good. Put a piece of 4in. in its place and no drone at all even on the hiway. In fact it is hard to tell its straight thru going down the road with the windows up. Outside it is loud. Maybe I got lucky with the no drone thing but I would rather be lucky then good!

 

[MMeier]

Kill The Cat !!!!!! :d

 

[Chaw]

Seems like Jannetty did some tests keeping it in place? I would like to see a dyno run before and after.

 

[RankRam]

I lost my cat and it sounds pretty good. Put a piece of 4in. in its place and no drone at all even on the hiway. In fact it is hard to tell its straight thru going down the road with the windows up. Outside it is loud. Maybe I got lucky with the no drone thing but I would rather be lucky then good!

No drone huh, did you remove the stock muff too?

 

[steved]

I tossed mine. . Well, actually I kept in the garage it after hearing what they cost. :-laf I like it better without it. It sounds, runs, and smells better IMO. However, I live in a state where there is no emissions testing. If I did, I would have left it on. Then again, I have heard some people here say that the truck will pass the actual emissions test w/out it, but not the visual. Not really sure about that stuff as it doesn't really apply to me.

Me too... took it off, but kept it in case...



No resonation in the cab (but I have a short muff).



No power or mileage increase by removing the cat that I could tell...



steved

 

[sweeda]

I remove the muffler and left the cat. muffler shops in CA are restricted from removal of smog equip. it's got plenty of noise and will still pass a complete CA smog test when it is required. when not if, this is CA and we will more than likely be the first. big rigs are already required to do smoke tests. to keep the cab quieter try welding up all the stock clamp locations.