bnuk

ok this is kinda a long story...
I bought my integra GSR in virginia like 2 years ago as a theft recovery. The catalytic converter on the car at the time was having problems, so i bought some shitty aftermarket one. It didn't fit so i just said screw it and hollowed out the old one (most of Va doesn't have emissions). At this same time i had some money left over so i got a used DC sports header off of ebay. The header also didn't fit. At the time I just assumed that the guy had screwed me over. The reason it didn't fit was that the bottom piece was about 4 in. to long. Rather than going through all the hassle of trying to get my money back I just got someone to cut and reweld the end of the header back on, which worked fine. Now on the DC heaher there was an O2 port on the bottom end, which was cut out in the process of getting the header to fit my car. But this was okay because on my OE header/manifold there was no O2. but there was 2 o2 sensors on the cat (one on each end)

This setup has worked fine for the last two years, however now I am geting my car registered in PA i need to pass emissions. So I bought a Carsound (Magnaflow) Cat [#22639]. I just picked it up today and when I started looking at it i realized it is not gonna fit. There are two differences between the cat on my car and the car sound cat (These are the same reasons the aftermarket one would fit):

1. The angle between the flanges is different, that is if i were to bolt it to the header, the 3 holes in the flanges on the other end would be off by about 20 degrees. however it is the right length.

2. The car sound cat only has an O2 port on the exit of the cat. while the one on my car has one at each end

For starters can you guys fill me in on whether my header is supposed to have an O2 port on itm, and if it is, why the hell didn't mine? I have no reason to believe that the exhaust was not completely OE when i got the car, and yes, I am sure this is a '98 GSR

It is kinda hard to describe the angles of the flanges without pictures, but if anyone knows what is going on please help me out.

Tobra

Are you sure it is a B18C1 motor?

westcoaststyle

First off, I know for a FACT that at least the 01 GSR had different rotations on the flanges than the previous years - 99- I think. My buddy and I went to install an N1 cat-back on his 01 and it wouldn't bolt up because it wasn't made for the 01, but rather a previous year so the cat flange was at a different rotation than that of the exhaust.

Not everything on the exhaust system is the same from 94-01. Maybe that will give you a little insight.

bnuk

that sounds like the exact thing i am dealing with. Was the exhaust the right length, or was it just the wrong angle on the flange? and yes I know am working with a b18c1. As far as i can tell the only thing that wasn't stock on this car when i got it was a CAI and a short throw shifter. (and all of the interior and wheels, because they were gone.)

JimBlake

Sounds like you've got a mixed-up set of exhaust stuff from different years. My '95 GSR has the O2 sensor located in the cat, but it's upstream from the catalyst material. So the A-pipe is a little shorter & it doesn't have a sensor bung. Later ('98?) they went with a longer A-pipe with the bung, & a shorter cat without the bung.

Maybe you gotta cut your losses & get an entire exhaust system from some single model-year. Pick the most expensive part, keep that, & get everything else to match that year.

bnuk

hmmm. but what year has 2 O2 sensors on the cat? my cat has one at each end of Cat. could it be that this exhaust is off of an LS? I thought maybe the junkyard threw on an exhaust from some random integra just to make the car run. But that doesn't make sense either because I did the orignal exhaust work like a month or two after I got the car and everything was real rusted and seized up, no way those bolts had been touched in a long time.

TheOtherDave™

On the bright side the flange angle issue is fixable, but it seems like the upstream o2 sensor ought to be mounted in the header, like it is on my 97 LS.

If you're looking for the best possible performance, I'd fix this problem at the header.

Buy an unmolested header for your specific model year. Then using the stock springbolts and doughnut gasket, bolt up the Carsound cat. Lastly, trim or extend the exhaust system as needed.

Later on, upgrade the cat-back section.

bnuk

but having a header with no O2 sensor is not uncommon, here is picture from an ebay auction for a '98 GSR stock header.

you can see that the bottom bracket and the flange are right on top of eachother, no room for an O2 sensor. this is how mine looks.

its an ebay link so if its dead just search ebay for an oem GSR header. there is almost always a couple on there.

bnuk

ok, just finsished calling car-sound. Apparantly the CA-spec integras have one O2 sensor on the header and one on the converter, this means that the CA-spec headers are longer. Non-CA integras have both sensors on the converter and have the shorter header. Odd thing is nobody sells "CA-spec" exhasuts components. You would think if they were different, parts would be specified as such.

TheOtherDave™

But....my CARB-legal DC Sports Header has an O2 sensor bung on the header - about 2" away from the bottom flange. I'll swear to it on a stack. Oh, wait a minute..:doh::reechy:

:loco: Let me step back a second...and look at the whole picture. h:

• Your GSR is from 1998, and thus it's OBD-II.
• Since it's OBD-II, it would need 2 o2 sensors, one before and one after the catalytic converter.
• So a 1998 GSR Header (stock or aftermarket) ought to solve the flange angle problem.
• Since an upstream o2 sensor bung is missing from the Carsound cat you have now, exchange it for one that has a bung at either end.