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So, in an attempt to switch my 02 DX exhaust to an EX exhaust I have run into a small problem. I know that you have to replace the cat converter when you put the new header in and that's where I have run into a problem. I purchased a universal cat thinking I could just have them weld it into the pipe, but because I have the DX headers on there now with a magnaflow exhaust without the ex extension piece, the pipe doesn't have the correct bend or flange. The guys that I had putting it together for me told me that it would be really expensive to fab something to make it all fit.

So, i thought I could possibly buy an EX downpipe/straight pipe or something to that nature and just have them weld it into that and then cut the cat-back and put the flange on that (or just weld it to it). I can't seem to find a downpipe that has a 2.25" in and out and most of them have a resonator where I would want the cat put in. I am wondering if I should just buy a cat pipe and sell my universal cat. But then there is another problem, where can I find one that's not $200+??

Any one have any help on this?!

 
Rep Power: 303

ok you will need an ex header ex cat pipe and ex exhaust either aftermarket or stock, or you will need the lx header ie: obx, the tanabe extension pipe and ex cat back. dependant on which way you go you will also need the ex swaybar and you WILL need to extend the o2 sensor wires.
there is only 1 place that makes a cat pipe for the ex and its random tech. its the only place that is 50 state legal. otherwise your in for a resonator/fake cat pipe to make it work.
1 thing you want to keep in mind is that just any universal cat will not pass smog. inspection is different in NY than in CALI so you may want to research the applicable laws in your state.
it really shouldnt be that expensive to have a shop fab it up maybe like $50-70 at most. any more and they are just ripping you off. it should take more than a half hour to do the work..
if you have any questions at all dont hesitate to ask, i have done this swap on my lx and as well on a coupe lx with different parts. there is only 3 ways to do it and i have done 2 of them

 
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I have a DC 4-1 ceramic, and the O2 extension wires. I bought a universal magnaflow cat that says 50 state legal. If I bring it to a shop like meineke or monrow can they fab something up? Like, what I mean is will they know where to bend, and how long it should be, etc?

 
Rep Power: 303

i used the dc 4-1 ceramic with the random tech cat pipe and greddy evo 2. any competant shop should be able to fab it up p[retty easily. you may want to stray from a well known branch type shop and try to find a muffler hitch and welding shop. they will do it for sure and it will be easy for them. you may want to buy a resonator pipe and remove the resonator and have the cat installed in its place. that is another idea if the shops arent wanting to help.

to keep the cost down you should just go with an rsx s exhaust and have it fabbed too. it should only cost you like $50-100 for the entire set up and you shouldnt lose as much bottom end.

 
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Thanks for all the help, but I guess my main question wasn't "what should I do" but more "where can I find a decent resonator pipe/cat pipe that is 2.25" in/out or a cat pipe that doesn't cost $250+"..

I searched ebay for downpipe / straight pipe / cat pipe, etc.. and all i can find are 2.25" in / 2.5" out pipes. And I can't seem to find any cat pipes except for the random tech ones that are $280+ at dezod and a couple of other places.

:: EDIT ::
Just been looking again and thought about it. If I buy a downpipe / resonator pipe that is a 2.25" in / 2.5 out and then cut the resonator out and install the cat, it will be 2.25" out cause that is what the cat is, right?

 
Rep Power: 303

the piping on a 2.25" in and 2.5" out is self explanatory. the section before the cat is 2.25" nad after is 2.5" so to answer your question directly NO.

but to offer some other insight the pipe is straight with a bend down from the manifold/header. the rear section can be copied in a 2.25" at a shop if your desire is to have nothing larger than 2.25". but i believe almost all the cat backs offered are 2.5". i personally think 2.25" is perfect if not 2". the stock is 1.5-1.75". increasing the dia of the piping only decreases the amount of torque the motor will produce at a lower rpm but open it up on the top end.
you can just use the 2.25" in and 2.5" out and use a .25" reducer to make the cat fit that pipe where the resonator once was.
usually you cannot modify any pipes that have the cat present and pass inspection, but once again that is cali. you may want to reference your state laws in regards to this

 
Rep Power: 247

so u got ur exhaust setup to pass smog here in cali? there were so many restrictions i scrapped the whole idea of converting to ex exhaust and im just getting 2.25 piping from the header/cat back through a vibrant resonator and a magnaflow muffler.

 
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For your EX exhaust conversion you can use this:

http://dezod.com/pd_megan_racing_high.cfm

Less than $100

 
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that pipe will require you to replace the swaybar. the resonator looks to be the same as the random tech cat pipe as far as size.

 
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Not true. I had the RT pipe on my stock EX and had a stock sway with no problems.

 
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I have already replaced my stock DX sway bar with an 03 EX sway, much smaller in diameter. The DX is fatter and hollow, where as the EX is thinner and solid..

I am also trying to purchase a used RT cat pipe right now from a guy and just scrap the whole magnaflow universal cat / create my own pipe idea. I'm keeping my fingers cross that I get it.. if I do, it will make things sooo much easier (and probably more legal)... but thanks Dezod for the link and Fam for the help.

 
Rep Power: 303

exactly my point you had and EX already. he has a dx/lx. using the R/T cat pipe on an dx/lx requires you to use an EX swaybar. believe me i know this from personal experience. the LX sway will not fit with r/t cat pipe

 
Rep Power: 266

ok so i have a question on the lx ex swap... i have a 2001 lx sedan auto and i just bought an megan racing axleback form another member ... couldnt find it on their site but it it fits and sounds decent im happy for the price i payed.. so my question is if the axleback fits can i buy the ex test pipe and header to replace the rest of my exhaust? will everything line up? is it going to be crappy sounding ie "fart can" at any rpms? you said the sway bar may be in the way so is there an after market that will allow it to all fit? thanx for your help

 
Rep Power: 388

^^^^^
well... you have it hooked up already? The dx/lx exhaust is a straight back pipe from the header to the muffler tip. SO if its on, you got it custom welded.. which you'll have to bust up if you get the rest of the ex stuff on there.

I'm assuming that your muffler connects to the pipe at about your rear axel... the ex piping will go to the ex header, to the downpipe, which has the cat at the end of it. Then from here to your axel back, you'll need a pipe, probably with a resonator in it so your exhaust isnt crazy loud. I'm not sure of the pipe hookups in the ex after the catback, but if its one pipe straight back to the muffler, you'll need to get some more pipes.

If you wanna use your stock lx piping, dont. Its ridiculously thin. No point in getting the free-er flowing header with the fat downpipe, then constricting the flow until it hits the muffler.

 
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Well, as for the swaybar, a stock ex, or aftermarket ex sway will work. After I did this conversion (it turns out to be a rather pricey conversion), I too my front sway bar off. I tryed it with the cat shield off, and it still didnt fit- so everyone reading this, dont bother trying to take the bolts off while your under there, its a pita and doesnt fit- my time loss is your gain.

Anyways, after I took it off, my cars handeling is more accurate-- lol. My tighter turns feel much better. I might try a sway on the front later down the road, but at the moment, i'm loving it off. Saved a good amount of weight up front too!

 
Rep Power: 247

yes wat Triz said. the header and test pipe will fit uld just have to cut ur current exhaust piping and replace ur sway bar for an ex one. as for the loud exhaust, a lot of ppl leave out the resonator, which suppresses sound, this makes it a lot louder but increases airflow