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Discussion Starter · #1 ·
the dynomax is just too quiet on my 02 and i want to do true duals on it. couple questions. i noticed that after the rear 02's and the Y-pipe, there's another cat. is that a third cat or just some kind of expansion chamber of some sort? there's no sensor after it that i could see, so removing it shouldnt hurt anything, would it? idealy i would cut the Y-pipe and just run back to 2 14" magnaflows. is the Y-pipe on there 2 1/4" before the Y? id love to do an X pipe inline, but i think the duals will be running too close together to fit a pre-fab one in.
 

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yes it's a 3rd cat, and yes dodge is retarded for doing that. i removed mine, but good luck getting an inspection done w/o it. there's no way a shop will pass it ever again w/o all the emissions components intact. to make them happy you could leave it on one side and just hollow it out, or run a pipe right through it to make it look like it's there at least.

for my duals i removed it. i would also recommend getting a full replacement and not trying to reuse the stock y-pipe because that is the most restrictive element in the exhaust system. rip it out and replace it with all new 2.5". i put in small round cats to replace the stock precats and keep the O2's functioning like they should. you should always use some type of crossover pipe on duals. i used a magnaflow x-pipe and it fits just fine with the pipes running side by side. you could always make your own though out of 2 90deg bends or use an H-pipe which has a totalyl different sound, but isn't as good for performance. that was a muscle car thing for sound.

duals will be louder, but the 4.7 runs the best on a single 3" system unless you are planning on adding a bunch of supporting mods for this? don't go any larger than 2.5" for duals, and if you are stock and staying stock i would do 2.25", but still use 2.5" for the down pipes.
 

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^ So if you remove that 3rd cat it isn't going to throw any CEL's right? We don't have inspections here so I wouldn't have to worry about that. Where/what all did you get for your pipes? I want to order up exhaust for my truck this weekend and have been having trouble finding anything as a complete system, and I doubt any shop is going to mess with it if I cut the 3rd cat out or if I ask them to.
 

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no codes at all as long as you keep the precats and the O2's hooked up where they should be.

i had a shop fab up my pipes, but it did take a lot to convince them to do it. they didn't want to at first either because of removing the cat, but it was like do you want $800 or not? and they did it. yeah it costs a lot, that wasn't even including the extra parts i bought because i supplied the muffers, cats, and x-pipe. that price was also for them to install my shortie headers.

if you were to do it yourself it would be pretty dificult w/o a pipe bender because a lot of the bends needed, especially if you are making new down pipes are not perfect 90/45 bends. it would take a lot of hacking and time to make these out of premade bends, though it could be done. i would do my own single, but prob not attempt duals. they also did an awesome job with supporting the pipes and keeping them inline.

you just may have a hard time getting a shop to do it for you cause they don't want to take the risk of you getting in trouble and it coming back on them. but if you don't have inspections up there, then you may have better luck.
 

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Discussion Starter · #5 ·
im not going to replace the entire system, there's nothing wrong with mine. and its a DD, im keepin this on the cheap i was actually gonna just continue whatever size the exisiting Y pipe is (2.25" ???) back to mufflers, then 2.5 out. ive already got a dual-out dynomax that came on the truck when i got it. i figured just pull the muffler, hang the new ones on each existing tail pipe, then make the 2 pieces to come off the Y-pipe after the cats. all i'd need to do is cut before the Y, then manipulate the 2.25" pipe slightly to run back to the mufflers. and i didnt think the 3rd cat removal would throw any codes, since there is no sensors behind it. so really, the truck wouldnt even be able to tell if its there or not since there's nothing to sense the exhaust after it.
 

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if you aren't going to do a full dual build, then why not just go 3" back from the Y-pipe and then keep the SI/DO muffer style but replace it with a better sounding one like a magnaflow. it'll be easier and cheaper that way and still offer good performance. no cutting the Y-pipe, and all you would need is some 3" pipe, and a muffler. it'll still be loud enough with a good muffler on there this way.
 

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Discussion Starter · #7 ·
if you aren't going to do a full dual build
it will be true duals, the Y-pipe will be cut BEFORE it comes together, just after the last 02 sensors, then the 2.25" pipes will both be continued to 2 mufflers, exiting in 2.5" tail pipe sections. im just not gonna replace cats to do it.
 

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i know you mean true, but i'm saying why go through the hassle. i wouldn't do it unless you do a full replacement, or it's not really worth it all. you said you were looking to save money and single 3" would help a lot, sound good, and perform better. just throwing it out there, but it's your truck.
 

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Discussion Starter · #9 ·
you said you were looking to save money and single 3" would help a lot, sound good, and perform better. just throwing it out there, but it's your truck.
i understand, but im not spending $800 to replace my perfectly good cats. im not trying to milk every single pony out of it i can. just running $50 worth of 2.25" pipe to 2 magnaflows at $80 a piece will be much more sensible for me. and remember, im in ny, so unless i dump over 1k on a complete stainless manifold-back system, this will need to be redone in a few years anyway. i could re-do it 4 times over the life of the truck and still not have it cost me as much as a complete system.
 

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If you are trying to stay on the cheap just take the 3rd cat out and leave the rest of your exhaust how it is. I would think (some else know?) that taking out the 3rd cat would add some more power to your exhaust, and I KNOW that it would make it louder then what it is now.

I was just looking on Ebay for systems for myself, didn't realize you could get the one in two out muffler + all the pipes for dual from there back for ~$150 shipped. I think my plan now is to just order one of those and take out the 3rd cat. But again, does anyone know how much of a difference removing that 3rd cat would make for power?
 

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Discussion Starter · #11 ·
If you are trying to stay on the cheap just take the 3rd cat out and leave the rest of your exhaust how it is.
i think i may do that for now, and see how i like it. ill wait and do the duals when i get my tax rebate for buyin a house. the hard part is gonna be NOT going to the harley dealer and gettin a Rocker C with that money, first :mullet:
 

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How do you guys find room for dual exhause under your truck, i don't even think i could get it to work if i wanted to with my spare tire in there. (don't want to take that out and put it in the bed)
 

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How do you guys find room for dual exhause under your truck, i don't even think i could get it to work if i wanted to with my spare tire in there. (don't want to take that out and put it in the bed)
My tailpipes fit around my spare.....
 

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Discussion Starter · #14 ·
My tailpipes fit around my spare.....
+1 for me. its close, but it clears. ive just got a catback now, but true duals are the same as a catback when it comes to the rear end of the truck.
 

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I looked up under there and it looks pretty congested getting around the spare, do you guys have the 265/70/16 spare with a hitch?
 

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Discussion Starter · #16 ·
I looked up under there and it looks pretty congested getting around the spare, do you guys have the 265/70/16 spare with a hitch?
yes, its just the stock size tire. and no, i dont have a hitch anymore. my pipes exit at a 45 degree angle from the bumper, not directly out the back. you could still get around it, you'll just be closer to the drivers side shock. anythings possible if you got the time and money.
 
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