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Hi Triz, I am fairly new to this forum and I just read a ton of stuff you posted on exhausts, however I am new and not familiar with this stuff.

basically my questions is what should i remove if i want a louder/deeper sound from my exhaust?

I was looking to remove either the cat/resonator or my muffler

not sure which is better for our cars (mine is 2003 civic ex sedan) because my friend removed his resonator for audi a3 and another removed a muffler for mazda 3, both sound great, so yeah just seeing if anyone had the experience of removing either the cat or muffler and straightpiping for the exhaust tone?

 
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I have a 2002 lx and I bought an exhaust system for an ex. I'm wanting to keep the stock manifold. When I went to put the exhaust on it was too short. Do I have to buy a header for an ex or what do I need to do? I'm not worried about having a cat and I have searched the forums like crazy trying to find info on this.

 
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Remove the whole exhaust and it'll be as loud as you can get it.

I'd say just get an axle back exhaust, aka just a new muffler and it'll be louder.

 
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You need an ex header and downpipe with cat.

 
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hey. i know this was posted awhile ago. but i just purchased a cat back exhaust for my 2004 civic lx(sedan). at first they told me the cat back(greddy spetrum elite exhaust) would fit both sedan and coupe. now that i ordered it they say it will only fit on the coupe version lx. im really geared into getting this exhaust and was just wondering wat the difference is and why they say it would not work. is it possible to get an adapter?

 
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It'll work. the underside of the cars is the same as far as the exhaust system is concerned.

 
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I just came across this.
Thought it would be good for a visual of the system.
(credit to trustdestruction on hondacivicforums)
DX/LX/CX/HX Exhaust Layout
(please note that components in the picture may not exactly match yours in color, etc.; however, this is the same layout)



The headers available for 96-00 Civics are only made for Civic EX%u2019s (except for one made by Magnaflow, but I am not going to talk about that because it is not as good as an EX header). Civic EX’s have a regular exhaust manifold, with the catalytic converter located directly after the exhaust manifold.

If you have an aftermarket catback exhaust on your DX/LX/CX/HX, then chances are, your catback looks like the one in the first diagram, but has a short removable ~16" section of piping, located where the catalytic converter is on the EX layout. In this case, when you get the EX catalytic converter, you just replace that short ~16" pipe with the catalytic converter. This ~16" section of piping is essentially a test pipe.

EX Exhaust Layout
(please note that components in the picture may not exactly match yours in color, etc.; however, this is the same layout)



There’s two things you can do - a wrong way and a right way.

The wrong way:
Install the EX header onto your car, and leave the catalytic converter completely out of the equation.

This is a bad idea for a few reasons:
1. It is illegal, and if caught, you will be penalized.
2. You will throw a CEL (check engine light) and the car will run in limp mode (limited power, bad gas mileage lower rev limiter, etc.) because the secondary O2 sensor will think that the catalytic converter isn’t working, or you may not be able to hook up the secondary O2 sensor at all.
3. Instead of CO2, NOx, and H2O, your exhaust will spew out hydrocarbons and poisonous carbon monoxide gas.
4. You will fail emissions/smog/inspection/etc.
5. A test pipe gives you only ~1WHP over a high flow catalytic converter. 1WHP isn't worth breaking the law and/or failing smog.
6. You will be polluting our air even worse than it is already being polluted.

The right way:
Convert to the EX exhaust layout by installing the EX header, installing an EX catalytic converter located directly after the header, and using an O2 sensor wire harness extension to relocate the O2 sensor to it’s new location on the EX catalytic converter.
You can convert using bolt on parts designed for an EX, or you can cut and weld the exhaust parts together as needed. You can have your original catalytic converter cut off and welded directly after the header if you want. The advantage to bolt on parts is that anyone can do it themselves with simple hand tools, and different pieces can be taken apart in the future if necessary.
Any method will work, as long as the finished product has this layout:

Converted Exhaust Layout
(please note that components in the picture may not exactly match yours in color, etc.; however, this is the same layout)



Items needed:
-EX catalytic converter
-EX header (a.k.a. exhaust manifold)
-O2 sensor extension wire harness
-EX aftermarket or stock catback exhaust (aftermarket DX, LX, CX, HX catback exhaust will work if it has the removable ~16" section that I mentioned earlier. If it doesn't have that section, the only thing you can do is cut the piping and weld the catalytic converter to the mid-pipe of the catback exhaust.)

 
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so basicly they dont make headers that dont require you relocate the cat?? that really sucks, i had to custom cut, bend and weld my cat back and now to put in headers id have to do it all over again? is it worth it and is the cat back useless because i have stock headers? also is the tiny bit of perfomance i may have gained from my cat back taken away by the fact that due to bored cops i had to put in a silencer?

 
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I have a 98 Ex. I bought a Apexi N1 exhaust kit. Well they sent me the Exhaust for Dx and want an additional 300 to send me the right one. So I'm sticking with what Ive got. Its a 3 piece system. How am I going to make this work?

 
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Same thing happened to me with the same exhaust catback for my 2004 dx... What I did was bring it to a custom exhaust shop.had them use what they can and fab what they had to to make it work was only like 120$ to instal and custom weld and bend pipes

 
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Getting a 2" downpipe for an lx, is it even worth it or will the dx/lx header/cat combo negate any restriction that would be lessened by the new downpipe?

 
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What if you were to remove the cat and open it and remove the internal guts and replace it back on a 2001 civic with 1.7 engine with the defouler mods would it work the same as a downpipe and not cost all the funds as I am very new at this trying to get by old and retired just trying to find the cheapest way to fix without have to buy a new cat please reply and let me know willing to try anything as the cat is bad thanks in advance

 
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sorry did not add that it is civic lx

 
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came across a ex exhaust and wanted it but i have a dx :c
anyway, got the ex headers and did the swap
just some side by side pics cause it might help someone
who knows



not to sure why the first to were flipped but w/e

 
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That isn't a stock ex exhaust, is it?

 
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nonono
its a meganracing for an ex, and a random tech high flow cat.

 
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Hey honda fans,

I need your help please ! today my girlfriend & i tried to fit wrapped buddy club racing headers on my B18C ITR but impossible to pull it up into the two studs on both gasket ends. This engine is installed on a 1995 eg6 hatch, we took the radiator stay off to move it a bit & see if it could help but we noticed that on the right side of the engine would it be the a/c compressor that blocks the way to install those headers on ? Would it mean i have to remove 1st the a/c system ?

In advance, we thank you for your help & answers,

Ashly & Marc.

 
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I've heard that a 2001-2005 lx/dx exhausts are the same, can anyone confirm this? I'm looking at a catback thats designed for a 2001-2003 lx/dx and I have a 2005 dx. I just want to know that it will fit before I order it. Thanks

 
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You said "If you want an EX header and stock DX/LX exhaust with a cat, buy a cat and take it to a muffler shop and they will connect the header to the rest of the exhaust and weld the cat in line. This is kind of stupid- see backpressure. You'll also run a check engine light. To avoid this- see O2 extenders / defoulers. "

Does this mean, buying a stock EX down pipe and fitting it in a DX/LX stock exhaust won't work?
I'll have to buy a separate cat from somewhere and weld it inside the stock down pipe from DX/LX?

Also why would it affect back pressure?
Doesn't the stock exhaust system already have a CAT already included in the stock exhaust manifold?

My intention is to buy a stock EX Header and buy a stock EX downpipe with the cat included, the thing is, I'm not sure if the stock downpipe from the EX will fit with the rest of the exhaust.

 
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They should be able to weld it in. My car is lowered, and someone ended up backing up into a curb when I lent them the car. It bent at one of the elbows near the front of the car. I hadn't planned out my car yet, so I was doing it piece by piece (big mistake) when we decided as long as we're replacing the pipe, let's get a nice muffler on there and increase the size. Down the line, I get a crack forming on my LX header. Did a little research (thanks to this thread), and got myself a DC header and EX downpipe/cat. The shop I took it to was able to hook it up to the pipe I already had in there from last time. I guess they just spliced where the EX pipe ended and hooked it up together.

 
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Thanks TRIZ for this great sticky. I have a 97 LX that I just upgraded the exhaust manifold and catback. When I was doing a Seafoam treatment I noticed a good bit of smoke coming from the original exhaust manifold. Removed the shield to find a crack. Followed your advice and found a great deal on the Megan header, used the Magnaflow free flow cat converter and cat back exhaust. Everything bolted right up. The 24" O2 sensor extension was just the right length. A bit louder than I was hoping, and there was a small but noticeable increase in performance. Now to see if mileage improves. Thanks again TRIZ for the GREAT post.

As a side note I had NO increase in mpg. Your experience may differ, but don't have high hopes for gains in mpg. Best thing about this is stainless doesn't need replaced. Thanks again TRIZ.

 
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Hi guys, great thread here. I am hoping someone could help me out with my issue. I will be replacing the headgasket, timing belt, and water pump next week on my 03 Civic LX. My exhaust manifold is also cracked and I would like replace this while I am already in there working. I really don't want to spend the $350 or more on the OEM exhaust mani. There aren't many after market headers for the LX but I found a few that didn't have the cat on it which are a lot cheaper. If I understand everything in this thread correctly I can use one of these aftermarket headers w/out a cat but will need some type of defouler or O2 simulator to keep my car from throwing a CEL correct? If there is a better option please let me know. I don't care about performance or sound, just reliability. This is my gas saving daily driver w/ 340,000 miles on the original engine and trans, gotta love honda's.

edit: yes I know my vehicle may not be emissions legal however my state does not check for this and I am looking for the lower cost solution here. Thanks guys!

 
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You've got the idea. I didn't do a thorough search, but I found your header/cat for about 500 bucks.

I was about to add up the price of getting a header (cheapest being about 200, more reliable ones working up to 370) and adding that to the defouler and whether or not you'd need to weld in a bung for the O2 sensor, but then I stumbled upon this from Procivic.com,

http://www.procivic.com/pages-produc...827/index.html

Looks like that takes care of the cat problem as well, and the price isn't bad. No experience with Magnaflow or this particular header, so that might need to be something you research, or other forum members can give their .02 about. I would usually argue for maintaining Honda parts if you're looking at reliability, but mine cracked as well (just under the 100k miles point...), so maybe this would be the exception to the rule and let someone else try to make one.

 
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Thanks Matt, it does seem like the exhaust manifold is the weak link on these cars based on the research I have been doing. But I'm not going to complain, the car has been great to me. I guess I under shot the price a bit, the cheapest manifold/cat combo I found was at autozone for $270, it was a Walker brand I believe which I have no experience with. All the rest are well over $400.

That magnafllow seems like a pretty good deal I'm surprise I didn't stumble across it yet. Right now it seems like the best option. I'm not fond of putting cheap parts on my car, and especially not thrilled about using a cheaper header that doesn't have a cat on it. Not to mention having to use a defouler as a work around for throwing a CEL. In my opinion a work around is not a fix. Thanks again Matt for taking the time to help me!

If anyone has any experience with the mangaflow header please let me know. Thanks!

 
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So the manifold on the lx/dx is a weak point on our cars. How about the ex, since the ex doesn't have the cat in the manifold does that mean there would be no improvement upgrading to header? Just wondering if it is worth my while

 
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It would be an improvement since the Ex headers have longer runners and they appear to be of similiar length. Adding a high flow cat would also help.

I'm not upgrading until my cat is bad not worth the money for the little gain, IMO.

 
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question to anyone that can help!! i got some speed daddy headers since my stock headers have been cracked (by the mechanic!!!!) and everything else on my car is stock... what i want to know is if my car will still pass smog even if i connect the oxygen sensor back on? Im a girl looking for simple answers please help!!!

 
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First of all Hello nice to meet you all

Second of all sorry if my question has been answered or is annoying. Speaking of annoying. Buying 2003 Civic LX exhaust parts!

Can someone PLEASE explain this BS to me?

What is number 11? Listed as Pipe B, Is that the downpipe for an LX civic? What is number 12? Is that just the main pipe? I can't find that by itself anywhere. None of the genuine OEM sites will let me buy that part. Is that a resonator on the end of it? What is number 4? Is that an EX downpipe with a cat? If I knew what the pipes were actually called (Pipe B means nothing to me I can't find that on ebay or amazon) I could find them. I'm replacing the manifold for another manifold. I have an after market header on their now and I don't want it. I want a stock manifold again which I have found no problemo. I have a feeling because the shop that replaced the piping had to shorten what they put on there to line up with the aftermarket header it may not line up and connect to a stock manifold. No resonator anyway I'd kind of like to have one.


What is that part 18 connected to the manifold? Surely not a downpipe with cat for an EX model, why would you connect that to an LX manifold which is evidently shown in the image? EX's don't have the cat built in correct? So what is that part do I need it? Is that the downpipe with resonator for an LX?


Finally what is pipe A? is that a downpipe? Is that something I can buy separate? Is pipe B the whole thing with resonator minus the downpipe? Why is this pipe B different from the other pipe B? I found this image on a hondatech thing where you pay someone to answer your question. Anyway the customer was asking about an exhaust for their 02 Civic LX I believe and the dude posted this image as reference. Nothing else about it.


So here's the deal. From what it looks like where they welded it from what I saw breifly looking under my car a bit ago it look like I can keep the muffler that's on there now. I know an EX downpipe won't work on an LX manifold because it is too long and has to include the cat yes? So after the cat you have this sort of bent section of pipe to connect the muffler too correct? So I'm thinking I should just be able to replace the downpipe with resonator and connect that to the bent pipe that connects to the muffler correct? I have no idea because it's all so varied. Honda sure is annoying with their exhausts :/ especially with the LX. Anyhoo I can't find the entire exhaust system for an LX without buying a $500 magnaflow or something similar. All the aftermaket systems I find for less than $300 are for the EX only :/ I'm also looking for stainless as I have a lot of salt. I can find what I'm looking for, for the EX but not for the LX. So I'm sure someone will ask "why don't you get an EX system manifold and all and just install that since you can find EX stuff what you're looking for so readily?" Can I do that without modifying anything? I CANNOT do any welding I don't have access to a mig or tig that is capable of welding this kind of material. And I am not paying the shop to do it. I've been to several shops in my area, all of them are untrustworthy and do poor work. I'm installing this myself. I can do it I just need to know which parts I actually need for my LX civic and I need to find them. I'm on a budget I have to make do. Any help would be appreciated. Sorry for the long post it's hard to explain what I'm doing, what I'm looking for, what issues I'm having, and everything, it's all so super stressing.

Thanks for your time. So now I'll explain how much I love trying to find all this info out by using the snazzy emoticons on the right:

 
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So to clarify. Can I just put ex headers and ex cat back exhaust on my lx coupe ?

 
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i have the magnaflow header/highflocat 1 piece for my LX (this is not universal part it is direct replacement header and high flow cat from magnaflow). it looks nice sounds nice and seems to help a lil w/accel but no huge diff (mine is automatic as well). the stock OEM heat shield on the top of header fits, but the lower one does not/...(no issues with o2 sensor or anything, passed inspection no problem with this magnaflow 1 piece and other bolt ons/basic aftermarket parts).

im thinkin installin a universal lower heat shield cover that fits with adjustable circle clamps (not tape), since the lower OEM doesnt fit w/magnaflow... legit?