Rep Power: 0

ok so if i buy a stock ex header it should bolt right up
to my lx right ? my second question is i know if i do that i wont have a cat
anymore so im gonna have a high flow cat installed under the car will i pass smog
with a stock ex header and high flow cat on my lx ? and since i am installing a stock header
i dont have to get a a downpipe since the lx has straight piping from the header back tp the muffler?

 
Rep Power: 0

high flow cats are street legal?

 
Rep Power: 367

goodie another header thread I can reply to!

okay.

EX header doesn't bolt straight up.

u'll need to have a downpipe made... and u'll also be eliminating ur stock cat convertor if u use an ex header...

so yeah ur cat convertor is gone... and u can get an actual highflow cat (with actual catalyic in it)... and in a sense your emission probably wont be effected much.

but you still wont pass smog... cuz you're not using the stock cat. plus, most states has regulations in using aftermarket cat... you have to show proof that there's a defect in your stock cat... or that you have used ur stock cat for a certain amount of miles. (more than 50,000 miles)

highflow cats are street legal in a sense with condition.

the HP racing 4-1 "highflow" cat is not an actual highflow cat... so its not street legal.

instead of explaining further. I'll let pictures do the talking:

EX Exhaust Manifold (aka Header):



DX/LX/HX Exhaust Manifold:



you can see that there's a cat convertor there... look how small the actual header is! ouch!

here's the rest of the exhaust system:



all of #4 is for the EX.. you can see the downpipe welded to the cat convertor...

and #12 is the DX/LX/HX's long mid pipe all the way to the resonator...

this is where some of the extra 12 hp and some more amounts of torque are coming from.

a better flowing exhaust system.

a Honda trademark. EX in most models usually have a better flowing exhaust system with other etc. such as variable valve timing and lift electronic control.

 
Rep Power: 367

oh yeah before someone ask where's the diagrams coming from..

its from www.hondaautomotiveparts.com

its a very helpful site for ordering and looking at parts diagram, when you dont have a service manual or something similiar.

 
Rep Power: 0

hey man thanks for the info kinda sucks it won bolt up
so if i was to use a ex header what would i do with the
02 sensors on my stock cat . move them and extend the wires
to be used on the "high flow cat" or what

 
Rep Power: 0

also i have a custom midpipe so i think i wouldnt have to have a downpipe made but i could be wrong

 
Rep Power: 0

never mind i take that back the ex bolts to the midpipe diff than the lx
so i would have to have one made

 
Rep Power: 367

yup.

and u gotta extend the o2 sensors...

one before the cat.. and one after.

 
Rep Power: 0

ok thanks alot for clearing that up
ok with that known what would take less modiifcations
a ex header or a aftermarket header .

 
Rep Power: 0

or i think it they would take the same mods right ?

 
Rep Power: 367

u can try the kamikaze dx/lx header...

which bolts straight up to the dx/lx exhaust system...

it eliminates the stock cat.

but at least it bolts straight up.. plus it has the necessary o2 sensor holes....

i believe the check engine light will come on though.

so you'll need to either buy an o2 simulator or ignore it.

but at least its a bolt on part... so when its time for emission check, u can just slap ur stock header and cat back in.

and er... there's a decent design to it.. its fairly similar to the ex header design..

 
Rep Power: 0

i have a lx, but if i buy an aftermarket ex header, downpipe, and cat--back exhast it should all bolt up, right?

 
Rep Power: 0

Wow, thanks for the awesome diagrams ! I was just wondering what the differences were.

 
Rep Power: 367

as long as they're all ex parts.. yes.

u can do a complete dx/lx/hx to ex swap.

should yield some gains there..

 
Rep Power: 338

the thing is, if u get the ex downpipe, u have to extend the wires to reach the o2 sensors and whatnot

 
Rep Power: 0

is it just me or does the lx header have smaller diameter pipes than the EX header.

 
Rep Power: 336

dont forget about the ex sway bar.

 
Rep Power: 0

so let me get this straight,

1. i take off my whole exhaust including the header on my LX

2. get a EX header with the downpipe up to and including the cat, then install a cat back system designed for the EX sedan/coupe.

3. get oxygen sensor wires extended to the cat which is now located under the car

4. swap the LX sway bar with a EX sway bar

that should be it..... if not let me know i could have missed something

i'm guessing that the lx and ex headers have the same pattern and bolt holes

 
Rep Power: 0

all this seems like a lot of work...why not just buy the kamikaze headers with an o2 simulator???...will the EX header swap give you more gains then the kamikaze headers???

 
Rep Power: 0

because then you can get the dc header and it will be carb legel for those of us that live in cali.

 
Rep Power: 0

oh i see...thanks for the info...i guess it's worth it

 
Rep Power: 0

how often do u do emission and smog checks? i was just wondering cuz i want to see if switchin between the HP header and highflow cat and o2 simulater and the stock headers and cat would be worth it everytime there is a check up

 
Rep Power: 0

how often do u do emission and smog checks? i was just wondering cuz i want to see if switchin between the kamikaze header and highflow cat and o2 simulater and the stock headers and cat would be worth it everytime there is a check up

 
Rep Power: 0

forget the post about the HP headers, just reply to the one with the kamikaze headers. SORRY

 
Rep Power: 0

i already have lx aftermarket headers that i know fit. got em on ebay. tried them out on my car for a week. wat if i order an lx COUPE cat back exhaust? will i still need to get the ex sway bar and just for the side that the exhaust is on right? and also have to get stock ex cat/piping from headers to ex cat back exhaust location beginning?

 
Rep Power: 228

lol i just posted this for some other guy, so you're lucky.

alright i'll set yu straight bud. please rep me for this since it's gina take me alot of time to do for you and i've never been reped even after doing this for like 8 people with very good info.



YOU DO NOT NEED AN EX SWAY BAR!!!!!!!!!!!


guys please don't give info if you have no idea what you're taking about. my mom has a 4 door lx and i hav a 2 door ex. they're the exact same car body (slightly diferent between 2 and four door). so the sway bar doesn't need to be switched which would have cost you alto of money. if you bought a cat. back for an ex the muffler will fit up and over your lx sway bar.




first off you need to know why you want an exaust set up.
power?
sound?
looks?

you won't make much power (hp or torque) even if you have a full setup, which i do.
i have
~k&n short ram intake, new $320 (but don't be stupid like me and buy brand nam, get it off ebay for $50 then buy a good aem filter)

~stock ex header (you don't need a bigger header if you have an ex since the exaust ports from the head match the header diameter. you only need bigger if you port your head)

~2in downpipe (not sure if it was stock buy it was on the exhaust when i bought her)

~2.25in megnaflow high flow cat. $100 new (make sure to get the one with the bunt whole for the air sencor between the two converter plates)

~2.25in megnaflow cat. back exhaust, $150 craigslist

~custom welded and cut for $170, for parts, labor, and tax.

with all of that i've seen minor gains in power and torque. my automatic is now at 8.2-8.5 seconds for 0-60, which is around the best time i've seen for a stock manual. so don't expect a rocket after you do intake and exhaust.

however it sounds amazing!!!!!!! and looks way better.

you also have to think about money. buying from ebay and craigs list is good for non vitale parts of your car.

now for your question. the lx (which my mom owns, has a very restrictive exhaust manifold, which has a built in catalitic converter. that will be your most restrictiv section of exaust flow. you have to remember that the smalest diameter size tube for your exhaust system (header,downpipe,cat. and cat. back) will be very restrictive even after you put a cat. back exhaust on, like you want. so if you want as much power as these bolt ons will let you have the ex header is definately better.

the ex header will bolt directly on to your lx head because both cars have the exact same engine. the lx has the d17a1 and the ex the d17a2 (there's also an a3 but don't worry). all the a2 means is that the ex has a vtec system attached to the same base engine that you have.

if you swap the header you'll need to buy a catolitic converter. what's nice is that a stock size cat., 1.25inch, is around the same price as a high performence high flow cat. (mine was $100 after tax). you'll also need to extend your o2 senosor.

there are 3 o2 sensors. one in your intake, one after the header and one in the cat.

the one in the cat. is the one you'll need to extend (just cut the wires extend with wire with high heat rated insolalation wire and remember to get the type of cat. with the air sensor whole in between the two converter plates like i mentioned above).

if you're just going for the exhaust but don't want it to do anything but look cool and sound a bit loader then just take what you bought to a GOOD exaust shop tell them to weld a pipe to extend it to the cat in your lx. they might need to add some 3bolt flanges but any decent shop can do it.

if you are going for the maximum amount of gains you can get off intake and exaust you also have to think about the diameter of piping you use. you need back pressure (i don't know the exact sciennce of it so google it). if you already baught a 2.5inch cat. back don't despare but try to get a 2.25in downpipe and cat. 2.25 is better for our car's since the engines are so low in displacment.

but if you're eventually going FI (forced induction, ie turbo or supercharged), then you'll want 3inch piping so your car can breath properly with the much higher volume exhaust of the FI setup.

2.5 is ok and alot of people us it even on the 7th gen civics, but i've read on this forum and others that 2.25 is best for NA (naturally asparated engines, so stock engines without turbo or supercharged).

 
Rep Power: 0

but wont geting a hi flow cat trigger a CEL? wheres a good place to get a mid pipe section with the cat in it? and wat do you mean the 02 sensor between converter plates? and will this fit up to my lx cat-delete headers?
not sure how to rep people.

would this fit my set up then?

http://cgi.ebay.com/ebaymotors/HONDA...Q5fAccessories

 
Rep Power: 228

no CEL light if you have the right cat.. there are people who mount the air sensor in the down pipe because after the lx to ex header swap they don't want to extend the sensor. but the civic sensor needs to be mounted exactly the same way it is in the stock cat. which is between the two catalytic plates in the catalytic converter.

the cat. looks like this ( l o l )

~the brackets, (), are the outer walls
~the "l"s are screens inside the converter. they look like a fine mesh, and this mesh converts (i think) CO to the less deadly CO2.
~the "o" is the air sensor in the middle.

you don't want this



where the sensor whole (bunt whole) is after the two iner mesh plates.

you want this


where the sensor is inbetween the two mesh filters, like it is in a stock ex cat.

secondly you don't buy mid pipes with cat's in them you just buy the cat. then get an exhaust shop to use a mid pipe to conect to the cat. back or your cat. back might be long enough to reach.

third you CAN NOT cat. deleat the lx exhaust manifold. the cat it built in to the manifold. the manifold needs to be deleted. then where it bolted into your engine head you bolt in the ex header or after market header. once the header is in then you attatch the down pipe. then the cat. then the cat. back.