I have a 94 gsr motor in my car, but it had the stock dx civic cat on it still and there is some type of stock manifold on the motor that bolted right up to the stock cat.

I was told that the gsr header wouldn't fit because of the different sized cats, am i correct?

My O2 sensor is on the header, and I am wondering if it is a stock 94-95 gsr header, or if it is from another car...would I be able to use a stock gsr header if i used a stock cat also? I'm asking because I wanna goto the ref, but want to have everything fully legit and stock before i do so.

 

well, im not sure of the location of civic sensors but, for the integra...at least on my 94 LS there is one O2 sensor and it is on the header just prior to the cat. I couldn't really figure out what you were trying to ask but i think your asking if the OE integra cat will bolt up, and yes it will. But only to an integra manifold or aftermarket header.

please clearify

 

Sorry, I was just trying to figure out how to word that.

I am wondering if the sensor placement is different between the obd1 and obd2 gsr's. And if it is the same for all models or different for the gsr.

Some guy is selling his stock manifold, cat, and intake stuff for 150 and I was gonna buy it, but I dont want to waste money if I already have a gsr manifold.

 

ok, thats WAY better. I can see you already have the GSR motor and the exhaust manifold is what im assuming you are talking about. If you already have this you dont need a different one. Chances are that it will go as soon as you do some research and get a decent header for that swap. Now, your car is indeed OBD-I. The obd2 has 2 O2 sensors. One prior to the cat located on the manifold/header just before the flange AND one in the cat itself. It is ontop of the cat. Im not positive where exactly in relation to the center, front or rear of the cat because i havn't ever seen one, because i have a 94. If you have the stock exhaust hardware in your civic the the cat really isn't compatible as you know. If someone is selling the cat from a obd2 GSR it will work, just an extra hole for the 2nd o2 sensor.

My suggestions: junk yard time. Find what you need at a yard.
or start saving for aftermarket stuff. If you are running exhaust gas through the stock civic plumbing you are killing the performance by not allowing that engine to breath correctly. However if you want the stock exhaust i would get stock exhaust from a GSR or ITR even. Which is hard to find intact unless yo uknow someone who recently took it off there own car. The 2 stock integra exhaust systems may not fit underneith the civic perfectly at all but with some help from a muffler shop this is do able.

Again, i simply recomend getting the correct OBD I cat or get a highflow cat and then an aftermarket header and catback system.

 

bump

 

Well in all actuality, I DO have an aftermarket cat, its a 2.5" but the muffler shop that installed it was ghetto, and they used the flanges off of the stock civic cat

So now my 2.5" cat is more like a stock cat, as flow isnt really helped any...which is why I was wondering if I could get a stock GSR cat and swap them until I have a JDM header and all the associated items that go with it. (i have the flange and gasket, but not the header, and I still need a flange that will connect to my Apexi N1 b-pipe)

 

ok.... the straight answer is.....

the only O2 sensor on the OBD1 GSR is supposed to be located in the cat. Only OBD2 GSRs have a sensor in the header (as well as the cat). Hope that was the answer you were looking for.

 

Thank you very much. That was exactly what I needed to hear.

So that means when I buy a header for my gsr it probably wont have a hole for the 02 sensor on it then right? And since I dont have one on my cat currently, I can just get one welded on. BUT, what if it DOES have an O2 hole in the header and I already have one on the cat, is there a plug they sell???