Rep Power: 0

I have an 02 civic lx i really want to buy headers and a new exhaust system but i was wondering are the quality of the headers on ebay are good enough to buy also some of the headers have the upstream and downstream sensors do i still need to put a catalytic converter if im going to buy a cat back exhaust system

 
Rep Power: 229

it's a header, not headers. headers would be placed on a v6 engine, where you have exhaust coming out two different sides of the block. our 4 bangers only need one header.

i wrote this next part for an ex header, but it's the same as an ebay header. for a header you really should just get an old ex one from a scrap yard, the larger size aftermarket headers aren't going to give you any more power because the size of the exhaust ports on the head are smaller then the aftermarket headers sold. they'd onley help i foy port and polish your head, and that's onley really effective if oyu boost 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

Okay, I've put on a megan race header. I do still have the stock system the rest of the way. So here's the plan or plans. Either Y it out and make some lake pipes along the bottom of the car or just do a single exhaust and run the exit through the centre of the bumper. I'm thinking that i'm gonna use a 2.5inch cherrybomb for the main pipe instead of just straight pipe. After the cherry bomb i'm thinking of using a flowmaster hushpower muffler. Has anyone on the forum used a hush power exhaust? I'm sure that the cherry bomb is going to roar like a M.F. Any ideas?