dsj51

Hi everyone. Have a 99 civic lx and im tryng to figure out what to do, and im lost. I have what looks like an exhaust manifold-header/catylic converter combo. Well 1 of the pipes is cracked. Can i switch to a 4-2-1 header and weld a cat under the car instead. Also, i believe my car has a precat. Do they make 4-2-1 headers that accept them. I found some headers, but they had no hole for it. The downpipe on the car is also cracked. Would 4-2-1 headers eleminate that pipe?

B_Swapped93

LX so the d16y7 engine which has the cat right in the manifold it's self. and im guessing one of the pipes leading to/from it is craked. you can get a 4-2-1/4-1 but you'd have to cut a chunk out of the exsisting exhaust to make it work along with extending the o2 sensors. my .02 just get a new d16y7 manifold can be found on ebay for cheap.

Junbug871

I HAVE A QUESTION NEED SOME HELP..... I HAVE A 96 civic with 17 and I want to know what's the lowest I could go with out having any problem with turning and I want to use springs

B_Swapped93

Don't thred jack ! start you'r own thred you can... this isn't even CLOSE to the thred topic.

dsj51

Ok, so extending the o2 sensors is just splicin the wires right? And looking at pics, it looks like it would eleminate the downpipe. As for cuttong the exhaust, not a biggie. Have welding buddys eager to do it lol. And another thing, i was gonna go with a flowmaster 60 series with the stock resonator in place. Would i still weld a cat under there somewhere?

Laughing Man

If you are loacated in Ca. you can not do that and pass smog. My exhaust mani is cracked as well, right at the upper O2 sensor. I just left it like that since all Ca. compatable mani/cat's cost over $600, even on ebay.

B_Swapped93

yes but there's also a plug you can buy that does it for you. you'd have to get rid of the stock resinator first. but as laughing man said this won't be "smog legal" if you live in california. in short it's an easy job you've got friends with welders most ppl that ask these questions don't so ya you can make it work with little effort

dsj51

Luckily im in NY. So then what about the pre-cat? I havent found 1 aftermarket header that specifically said it wasnt pre-cat compatible. Are all aftermarket headers like that? Is the pre-cat normal on civics? I didnt want a super loud car, so was gonna keep the stock resinator for thst reason

92lxsleeper

get a header, an ex cat, and an ex mid pipe. extend your o2 sensors, and enjoy having a normal exhaust

B_Swapped93

no the y7 is the only one with that set up all others have it after the header. no it won't be any louder

hunan beef

Probably the best thing to do if you still want to follow the law. Probably wouldn't hurt your pocket much if you grab these off a 4 door EX at your local junkyard.

Otherwise, you can stick an aftermarket "header" on there and extend the 02 wires, no need to cut or extend any piping. It will bolt right up. I was in your situation and ended up going this route. One downside to this...is finding a header that has both 02 bungs (stock manifold has one on top of the cat and in the middle of it). I ran into this issue, most aftermarket manifolds only have one.

I have heard of tricks of leaving the secondary 02 sensor dangling away from the exhaust to prevent tossing a CEL... didn't work for me though lol

dsj51

I def want to pass inspection. Im gettin an idea of what to do, but still stuck on what to do about the pre-cat. Can i take that off without throwing a code?? Is it important?

B_Swapped93

You mean the primay o2 right ? extend it you NEED it if that's not what you're talking about what are you ?

hunan beef

If you were to put a cat after that "header" and plug up the 02 sensors before and after (assuming you have good 02 sensors), you should be fine and not toss a CEL.

dsj51

I might b mistakin an o2 sensor as a pr-cat. Where would the pre-cat b located? Would it loom like an o2 sensor?

B_Swapped93

Ok there's 3 things we could be talking about here: 1(orange)the primary o2 sensor 2(blue) the secondary o2 sensor(sits in the cat) 3rd(green) the cat it's self there's only one of those.

grumblemarc

iTrader: (4)

I am removing the entire exhaust system from my wife's hatch. Replacing it with an Ebay 4/2/1 header that has provisions for 2 O2 sensors, a Magnaglow replacement catalytic converter for an EX with provision for O2 sensor after the catalytic converter and a Yonaka catback exhaust. Bought an O2 extension from Hondapartshero's Ebay store and I'm set.

NOTHING HAS TO BE WELDED ON!

cvcrcr99

y5/z1 are the same set-up as well. We could go on and say many 01+ Civic are set up this way, too.

This. Just swap to EX(, or y8) parts and extend the o2 sensor(s).

dsj51

Thanks for the picture. It helped alot. Another question. Do i plug both o2 sensors into the aftermarket headers, or do i put 1 into the downpipe part of the headers and 1 after the cat in the midpipe? Ive also seen universal cats with a hole in them for the o2 sensor. 2 many wuestions. Sorry guys.

B_Swapped93

The primary o2 goes in the header right before the collector. The other(secondary) in the cat it's self.

dsj51

ok. so i found headers, but they say non-egr. im pretty sure my car has an egr, so can i use them? And also, im gonna buy a universal magnaflow cat with the o2 hole in it, good?

Laughing Man

Not trying to thread jack, but does anyone know if a y8 mani will bolt up to a y7?
I was toying with the idea of converting my exhaust to y8 configuration to make it easyer and more affordable fix for this issue. If so, it would be an easy fix for the OP too...

dsj51

found headers with a o2 hole on the header, and 1 on the collector pipe. seems to me the 1 on the header only gets 1 pipes gas, while the o2 hole in the collector pipe, gets all 4 pipes. which is the better spot to put them. say i put it in the collector pipe, do i still put the other o2 sensor in the universal cat? and do i put the cvat in the spot where my stock resonator is?

grumblemarc

iTrader: (4)

it anyway.

dsj51

So i figured out the pre cat is just the o2 sensor before the cat lol. Im about to buy headers with 2 o2 holes in em. 1 on the headers themselves, and 1 on the downpipe. Where's the best spot to put them, header or downpipe?