+MM+

I did some searching here for quite a while and couldn't really find any results regarding this. What is the ideal diameter for a cat-back system for a stock LX? A local shop wants to order me a 2.5" but I read somewhere here that this would be too big. Should I stick with 2.25"? Thanks.

ex-cobalter

What year????

A 2.5" may be overkill if you are running a n/a car. if you want a good exhaust, i would suggest sticking with 2.25". The car comes with a 2" system on it, so too much bigger, and you will be seriously risking a lack in pressure in the system.

+MM+

Sorry, it's a 2003 LX.

I'm surprised that this guy ordered me this system then. He owns a local performance shop and seemed to have been rather knowledgeable. Just goes to show you, do your own research before buying or installing. Thanks for the feedback.

ex-cobalter

anytime. FTR: i am an exhaust mechanic, and also work in a performance shop, but i drive a civic as well, that's the difference. The performance guys want you to buy the biggest system possible for your car. A 2.5" kit will fit, but it is really overkill for your car, and if you wanna throw codes, go for it. 2.25" kit is large enough to improve flow, but small enough to keep the computer near the specs as to not give you that red CEL on the dash.

+MM+

Hey man, if you wouldn't mind, seeing as you're an exhaust expert...could you please give me your opinion on this exhaust? This is the 2.25" system he will sell me. There is no brand name, but it looks quite similar to that garbage that sells on e-bay. The price is $280 Canadian. To me, it seems to be alright except for that rice-errific 4.5" outlet. Anyone else feel free to comment if you have a similar system. Much appreciated.

ex-cobalter

not too impressed with it. It's not the outlet that gives it the ricer sound, it;s the muffler itself. In all honesty, if you wanted to improve the sound, without going "super rice honda", try keepong the factory system, add some pitch by removing the resonator, and go with a magna flow or flowmaster muffler. I wouldnt trust that to fit on your car, where's the overaxle? if that slight bend in the pipe is the overaxle, you are in trouble.

civic-driver

iTrader: (4)

i had a custom 2.5" exhaust with a vibrant res and a megan racing muffler for almost a year and i never had any cels... what would make it have a cel? i just ditched it cause it was too loud but it did sound really good... was sooo deep. i would say go with a 2.25 helps keep the lower powerband... what little we have

ex-cobalter

quite often, when people go and try to change their exhaust, the shop's first instict is "can we sucker this guy into getting rid of the cat?" took the guys at my shop 4 months to get over that mentality with the OBD2 cats. The OBD2 cats are used in an exhaust setup where there is 2 oxygen sensors, one in front, and one behind the cat. If you change the cat, and str8 pipe, it will guarantee a CEL. If you install a system that doesnt create the right amount of backpressure, the second sensor wont get the right reading, and thus throw a CEL out of fault.

TRIZ

iTrader: (14)

That exhaust you have pictured wont even bolt up to what you already have without having some custom exhaust work done, or buying a different down pipe. Get your 411 at my exhaust FAQ- link is in sig.

+MM+

Problem solved. I ordered a Magnaflow cat-back system today. Thanks for all of your help.

civic-driver

iTrader: (4)

the cell associated with the cat being removed has nothing to do with back pressure in the exhaust system. the second O2 sensors job is to check and make sure that the cat is in place, it does this be finding a set difference in readings between itself and the first O2 sensor. if you remove the cat and are getting the cell (dont remember what it is off the top of my head) you can use two spark plug defoulers that cost like 5 dollars at most autoparts stores, drill one out .5" and stick that between the second o2 sensor and the dowpipe. It moves the O2 sensor out of the direct path of the exhaust gases making it read lesser than the first thus removing the issue that would cause a cell. there are also a few companies that make a "race header CEL fix" , omni power or weapon R. yes doing this wont alone you to pass a sniffer test with installing a cat if you have to but it will pass a visual inspection. I had to remove the cat in my LX when i got a new header and i have used a spark plug defouler for over a year with out any problems. Im planning on getting a universal OBD2 high flow cat installed within the next few weeks because i just got my new exhaust put on and i got to reinstall my header. the way my setup is i wont have the cat put in the stock location but i will still have it so i wont have a guilty conscious. I dont have to pass any smog in my area of colorado so some of others concerns dont apply to me. ok thats enough on that subject.

to the OP i have heard good things about the Magnaflow exhausts good choice. is the exhaust for a LX or an EX?

+MM+

^ It's a 2003 LX.

I'll be sure to post some pics of my car after the install this weekend. I've been meaning to take some good pictures of it anyway.

civic-driver

iTrader: (4)

i mean is the exhaust made for an EX or an LX/DX ? the first exhaust you showed (in the pic) looked like it was made for an EX if it was even made for our cars. The EX exhausts wont bolt up to your LX without an adapter pipe. As long as the Magnaflow is LX/DX specific then you are golden.

Look forward to seeing some pics of the car man.

+MM+

Then I guess I am golden I made sure this time.

http://www.magnaflow.com/02product/s...e=SPCT&id=3538

civic-driver

iTrader: (4)

thats pretty cool. they have the adapter pipe included and it looks like the flange to connect to an ex as well. looks good. get us some pics

+MM+

Well, I got the exhaust installed today. Unfortunately, it's hanging much too low (especially with the clamps, see pic). So I'll have to take it in to the shop and have it welded up. I'm impressed with the overall look and quality of this product though. Although it's not as loud as I had expected.

ex-cobalter

nice ride, love the all black look.

civic-driver

iTrader: (4)

definately like the look have going on very nice. I know you can spin the clamps so the bolts face sideways and it gives you the extra inch of clearance that welding probably would.

d17civickid

iTrader: (4)

very clean.. looks really good man.

maverick27

i
If you have the money go with a stainless steel exhaust. Otherwise go with the galvanized steel. Two and a quarter inches is perfect. You,re not boosted so you don't really need to go bigger. Sound along with perforfance and looks obviosly is the key. I,m sick of hearing these tin can exhausts on civics (supposedly with type R motors) day in and day out.