Eliminating upper Cat on stock downpipe??

[dued]

Car: 1995 S14


Hi, this might be a dumb question but here it goes: I currently have a stock header, stock downpipe, and stock cat with a 3" cat-back exhaust.

I noticed that the stock downpipe has a cat at the top of it, and a stock cat at the end of the downpipe. So I was thinking if I were to buy an aftermarket downpipe + test pipe, would the downpipe eliminate the upper cat? I know that the test pipe will eliminate the final cat, but my goal is to eliminate both.

[!Zar!]

The cat at the center is hollow on s14's. So a test pipe would be worthless.

Only the cat on the downpipe is an actual functioning cat.

[nismoracingsx]

Why would you want to eliminate both cats, and don't say for hp, for the love of god >.<

[murda-c]

The cat at the center is hollow on s14's. So a test pipe would be worthless.

Only the cat on the downpipe is an actual functioning cat.

My car had a cat there :confused:

[dawagarage]

does your car not have to pass CA emissions? if yes, how do you intend to do so with your cat removed? as for the 'pre-cat', i think its purpose is to serve as a noise reducer/resonator. when i replaced my stock exhaust manifold with a used hotshot header i scored off ebay, the car was noticably louder. i dont think youre going to find ka24de downpipes, etc. you should just replace the whole exhaust manifold, thus gaining power and eliminating the precat.
i heard DC was very good, yet discontinued, yet somehow theyre available here:
DC SPORTS 4-2-1 RACE HEADERS 95-98 NISSAN 240SX : eBay Motors (item 170472885151 end time Jul-13-10 00:15:20 PDT) (http://cgi.ebay.com/ebaymotors/DC-SPORTS-4-2-1-RACE-HEADERS-95-98-NISSAN-240SX-/170472885151?cmd=ViewItem&pt=Motors_Car_Truck_Parts_Accessories&hash=item27b0f9cb9f)
failing that, try to acquire a hotshot or pacesetter header.

[!Zar!]

My car had a cat there :confused:

Really? My s14 had a hollow cat on the bottom, and a fully functional honeycomb cat on the downpipe.

Same with another s14 I worked on.

I could be wrong. Maybe both just happened to have no center cat in my case?

[murda-c]

Oh i think it might be because my car is OBDII.

That's probably it.

[sirfallsalot243]

Really? My s14 had a hollow cat on the bottom, and a fully functional honeycomb cat on the downpipe.

Same with another s14 I worked on.

I could be wrong. Maybe both just happened to have no center cat in my case?

No, youre right. My S14 came with a hollow second cat. I would assume its because thats where the real cat would be on factory SR20 S14's, and since we got the KA with a cat in the downpipe, Nissan just threw an "oem testpipe" there. Every S14 ive worked on has been this way, OBD2 or not.

[Homer_Simpson]

No, youre right. My S14 came with a hollow second cat. I would assume its because thats where the real cat would be on factory SR20 S14's, and since we got the KA with a cat in the downpipe, Nissan just threw an "oem testpipe" there. Every S14 ive worked on has been this way, OBD2 or not.
My 95 does not have a hollow secondary catalytic converter. I was expecting a hollow cat when I bought the car but it was full of honeycomb.

[sirfallsalot243]

Interesting. I've only done exhaust work on 1 OBD1 S14, maybe it was already gutted when I got to it. I know my car's exhaust wasnt touched before me (obd2) and it had a hollow 2nd cat.

[S14DB]

Federal cars have only the primary cat. California (CARB) cars have a secondary cat.

[Homer_Simpson]

Federal cars have only the primary cat. California (CARB) cars have a secondary cat.
That make sense, I totally forgot about it being a CA car.

[sirfallsalot243]

That make sense, I totally forgot about it being a CA car.

And would also explain why ive never run into an s14 with a secondary cat.

Not too many CA cars make it out here to PA. :)

[SHINCHU]

i have a CA 95 with a honeycomb cat that unbolts from the downpipe. i could put on my SR test pipe if i want. no pre-cat.
however i might try to hunt down a CA OBD-II pre-cat style manifold if i have trouble passing smog? hmm... good thread.

[projectRDM]

SR downpipe and RT cat bolts right to the OE manifold, or buy a header and any aftermarket cat.

We've talked about this since 1995. Nothing has changed.

[DALAZ_68]

We've talked about this since 1995. Nothing has changed.

except for the crowd sir...:cj:

[!Zar!]

except for the crowd sir...:cj:

You're right.

They are even more lazy, and dumber than before.