Question about exhaust system/flex pipe?

[Teh Luckinator]

I was looking at my whole exhaust system, and I found something weird:

http://exel.fcuk.org/images/Lucky/wtexhaust.jpg

A while ago I looked it up somewhere, and it's... just there. It's not the cat, but some big ass hollow space. I'm just wondering, is it really needed? I really want to put in a flex pipe, because the exhaust system shakes like shit (it broke off the place where the cat and the exhaust join together... wonderful), but I'm wondering if that hollow part is needed. If it's for emissions, then I'm keeping it on for sure, but yeah. I'm just wondering what it does. And is there any other place I could install a flex pipe? I'm getting a new cat back exhaust system, so yeah.

[misnomer]

Don't take this as gospel, but I believe that is simply a resonator. Removing it may change the tone of your exhaust, but shouldn't effect performance or emissions. IIRC, the s14s had the resonators, s13s did not

[anthony240]

on my 98, that's where the cat is. on Zenki I'm not so sure.

[projectRDM]

All S14s run the close coupled cat. That's what that large item is at the front, right off the manifold. The second item further back is the resonator, followed by the muffler at the end, though yours looks to be aftermarket.

A flex pipe is best added in the downpipe, right after the OE cat, or if using a header it can be cut and welded in there, just before the resonator. You should also at least replace your OE hangers, or going to stiffer ones or even hose clamping them is even better to prevent further breakage.

[LigouriRd]

Not exactly true
'91-'94: beats the hell out of me.
'95: first bulge is the cat, second bulge is hollow.
'96-'98: first bulge is the cat, second bulge is another cat.

[projectRDM]

Not exactly true
'91-'94: beats the hell out of me.
'95: first bulge is the cat, second bulge is hollow.
'96-'98: first bulge is the cat, second bulge is another cat.

Wrong.

The second one can have either filters or be hollow, it depends on production line and what they had leftover to use. I've seen both on all years from 95-98. My 95 had filters in the second can, my 96 and current 98 do not. The last three cars I stripped (two 95s and a 97) all had filters, two or three out of the handful locally I work on also did, the rest didn't. There's no gaurantee what you'll have.

[LigouriRd]

I stand corrected
My '96 has two cats, granted the second one is much thinner in material. The '97 that my new engine came from also had two cats. A '95 that I helped out on had one cat and a hollow thing that looks like a cat (Which I wanted to buy so I did not have to bust mine out).