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Discussion Starter · #1 ·
I'm trying to put an exhaust on my car. originally i was just gonna go cat back, but after reading about the stock cat breaking up and going into the motor, i wanna go full exhaust. Here's what i'm planning:

Ebay Header
Megan midpipe w/resonator
cat
megan mo-e muffler

all with 2.5 inch pipe.

The thing is all the o2 sensor garbage. i've read about using the spacers and moving them off the pipe, but where exactly are the o2 sensors. Is it just the one cat in the stock manifold, or is there one lower? If i put on a header, will i have to move o2 sensors or can i just leave them where they are? please help me. haha
 

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On my phone, so I don't know what year you have. You have 2 o2 sensors; 02/03 have both o2 sensors on the exhaust manifold, while 04-06 have one on the mid/downpipe and one on the manifold. You need to space the second/downstream sensor, leave the first one alone. You should not have to move any sensors if the exhaust parts you buy have bungs in the correct spot.
 

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Discussion Starter · #3 ·
Ok, i have an 03. So if my header has the bungs in the right spot, i'll only have to put a spacer on the lower one?
Also, do i need a down pipe AND midpipe? and will a midpipe reach to an axle back?
And, i know i don't NEED a cat, but would it make it sound better? i'm not looking for a raspy or high pitch tone, i want a little deeper and quieter, thats why i'm not going with an N1 muffler.
 

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Ok, i have an 03. So if my header has the bungs in the right spot, i'll only have to put a spacer on the lower one?
Also, do i need a down pipe AND midpipe? and will a midpipe reach to an axle back?
And, i know i don't NEED a cat, but would it make it sound better? i'm not looking for a raspy or high pitch tone, i want a little deeper and quieter, thats why i'm not going with an N1 muffler.
Yes, just the lower sensor needs to be spaced. If you want a full exhaust with a 4-1 shorty header you will need a downpipe, midpipe, and axleback (or just downpipe and catback). The midpipe (at least what Megan calls a midpipe) will connect to the axleback.
I highly recommend a high flow cat, it will make your exhaust less conspicuous in almost every way.
 

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Discussion Starter · #5 ·
ok. I'm not trying to buy a whole kit, kinda just piecing together my own. but i want a resonator too.
 

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just buy a 4-1 header and a catback. that will keep the main cat in place and get rid of the precat, and any good catback will have a resonator.
 

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You dont have to worry about the cat on the exhaust itself. ONLY the one on the stock header. But if you want to get a high flow for an extra horsie or for sound purposes, go for it!! lol
 

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Discussion Starter · #8 ·
I'm super confused. So there is the cat on the manifold AND one in the mid pipe section? but the o2 sensors are only on the upper one?
 

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Discussion Starter · #9 ·
And if i get a header, will i need a down pipe to connect that to the Cat, then a cat back to go from the cat out?
So what all do i need to buy? a header, downpipe, and cat back system? leave the stock cat in the mid pipe section?
 

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Yes, two cats.
A complete exhaust would consist of a header, downpipe, midpipe, and axle back, in that order. A catback consists of a midpipe and axleback. You can replace whatever you want, many people just buy a catback and header and leave the stock downpipe.
 

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The stock downpipe is 2 3/8" and includes the second catalytic converter. If you remove it, you will need to cut one of your new pipes to weld in another converter, if that's what you want. A resonator in the catback will quiet the sound a little but the exhaust will not be as quiet as stock if you do a full 2 1/2" exhaust. Some people insert a second muffler to get a quieter exhaust.
 

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Discussion Starter · #14 ·
So if I just used that into the stock cat, then a 2.5 cat back (w/resonator), it should sound just fine? it won't make that much of a difference whether i use the stock or new downpipe right?
 

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The stock cat is pretty restrictive compared to a high flow unit, especially a high performance metal core cat. Also, the stock downpipe is crush bent, which flows 30% less than a mandrel bent one with the same diameter.
 

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Discussion Starter · #16 ·
Ok. well i know doing all this but leaving the stock car and downpipe will still add a little power, mostly i'm doing this for sound and so the stock precat thing doesn't destroy my car. I've never put exhaust on a 4cylinder, only V8's, so sorry for so many questions.
Do you think the set up i'm talking about will sound ok, or will it be hella raspy?
 

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In that case I would just get a decent header and leave the rest of the exhaust system alone. You may decide later to do the other changes.
 

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Depends on the catback and if it has a quality resonator and muffler. Generally brand name stuff sounds better than the eBay junk.
Check youtube for sounds clips.
 

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Discussion Starter · #19 ·
i found an SRS cat back with resonator built in. clip on youtube sounded pretty good. think ima go for. Thanks for all the help guys
 
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