Headers, Cats, Testpipes?

[nurseryboy]

I have a 3.5 Coupe and would like some help in understanding a few things with the exhaust.

1. I read a post that said that the catalytic converters are part of the headers. Is this true?

2. If so, would testpipes cause any kind of issues? Or, would they be replacing the cats?

3. If I got testpipes, where would the 02 sensors need go to prevent the CEL light from going on?

4. Would I need to put a catalytic converter anywhere? (For inspection and CEL prevention)?

Thanks guys!

[rcboy514]

1. No, they are part of the y-pipe.

2. If I recall there arn't any test-pipes available for the coupe. Check out the racingline y-pipe, I think thats the closest thing so far.

3. no test pipes

4. I'm pretty sure it's illegal to run without cats.

hope this helps

[nurseryboy]

Hey man, thanks for the reply.

1. It's my understanding that the Y-Pipe has one cat, but there's two others as well.

2. I'm talking to a local place that says they can make me some test pipes. I just got the Racingline Y-Pipe and want to open things up even more.

That's pretty much why I'm wondering about this stuff. Trying to see what drawbacks there could be with getting testpipes, and what I'd need to do if I would get them. I'm most likely going to be moving to South Carolina soon, and they don't have vehicle inspections, so I'm not too worried about emissions tests or anything

[Dexion]

There are 3 cats.

Two are in the stock downpipe's (right after the exhaust manifolds) and one in the stock Y-pipe. We do not have cats in the headers (exhaust manifolds)

[nurseryboy]

Ok, so removing the stock downpipes will be removing the two cats? That'll obviously throw the CEL. Do you think a high-flow cat on the Y-Pipe (once it's down to one pipe) with the O2 sensors after it would work?

[Dexion]

nope!

[nurseryboy]

Dang. So I'd have to do high flow cats on each downpipe with the sensors after each? Hmm.. may just have to put up with a CEL, haha.

[emprbasist]

There is another thread in this section about Fast Intentions possibly producing aftermarket downpipes for our cars, the first post shows the prices and there are three options for the cats: high-flow cats, test pipes, and resonated test pipes. All three are going to be offered at different prices (if it ever even happens).

[nurseryboy]

Yeah, I saw that (and made a few posts in it), but it doesn't sound like they're going to be making them So.. I was looking into the possibility of just having someone local make them for me. Not sure what I'm getting into though.. haha.

[doi]

you can make test pipes and run them without a cel being thrown. i know alot of cars that use it and im about 99% sure that it will not throw a cell with these. Im going to have a local shop custom make me some test pipes and maybe even some headers. This is what the part looks like that u need to make the ell go away while running catless downpipe.

http://www.evasivemotorsports....r.jpg

check that out they come angled or straight

[nurseryboy]

Interesting.. I was wondering if there was something like that, to simulate a working sensor. Thanks!

Does anyone who had testpipes made for them want to chime in and maybe give a little info on how they had them made, any issues, suggestions, etc?

[nurseryboy]

Ok.. So now what I'm thinking of doing is doing straight through testpipes (like http://fastintentions.com/exha...s.JPG) and using dummy O2 sensors (like http://www.evasivemotorsports....1R-DP) to try to prevent a CEL. Anyone see any possible issues with this?

Also, I already have the Racingline Y-Pipe and Nismo cat-back, and it's already getting a little loud/raspy for my liking, and I'm sure doing testpipes will only magnify everything. So, I'm thinking I'd get a resonator to install on the Y-Pipe. Should this help cut down on the raspyness? If so, any recommendations on a good resonator? I'd like to go for a mellow, smooth sound (as much as possible, considering..)

[rich2342]

Has anyone had any progress with this.

Is Fast intentions scrapping plans for test pipes?

i think we should get stillen and others involved. I for one would be interested.

[rcboy514]

I guess im kinda confused, so there are catted pipes (down pipes?) from the headers to the y-pipe? I would be interested is downpipes if it didn't sound obnoxious. more info plz

[nurseryboy]

Has anyone had any progress with this.

I never really got anywhere with it. I found more than one place locally that said they could do it (for me, not on a mass-production scale), but I haven't had the time to just leave my car there for a few days for them to fab everything up. I really wish there was someone who made them already..

I guess im kinda confused, so there are catted pipes (down pipes?) from the headers to the y-pipe?

Yes, headers to downpipes (2, each with cats) to y-pipe. If someone was making them, it should be a pretty easy install. I'd imagine we could get some power out of them too. Don't know what it would sound like, though.

[rich2342]

It would free up prob around 4-6 whp maybe more since we are fwd. The Z's are about that for rwd test pipes.

Resonated would be the way to go if they are produced. Very raspy without. It really opens the flow of the exhaust and with a Y-pipe/ exhaust would really be insane for our cars...

[nurseryboy]

It would free up prob around 4-6 whp maybe more since we are fwd. The Z's are about that for rwd test pipes.

Resonated would be the way to go if they are produced. Very raspy without. It really opens the flow of the exhaust and with a Y-pipe/ exhaust would really be insane for our cars...

Man, I'd love it if someone was making these! Fast Intentions is, but not for the Altima Coupe (near the bottom of the page - http://fastintentions.com/exha...t.htm). They say it added 9 WHP / 10 LBs TQ to a "bone stock" 350z. I agree that along with the Y-Pipe and cat-back, we could see some very good results. The Y-Pipe alone helped out quite a bit. Dang it.. Someone make these!!

[rich2342]

This clip is a stock exhaust with just resonated test pipes added. It is so much better.

We really need to get these done.

http://www.youtube.com/watch?v...om=PL

[rcboy514]

that sounds really mean lol I guess we better put our kissass faces on and start begging stillen

[nurseryboy]

that sounds really mean lol I guess we better put our kissass faces on and start begging stillen

Yeah, haha. I'll send them an email right now!

[nurseryboy]

Yeah, haha. I'll send them an email right now!

Ehh.. Maybe I'll hold off for now. I think all of them are up in Newfoundland right now with the targa rally. No use bugging them now if they're pre-occupied with that.

[razah9]

I'm not going to get a cat-back so would a non-resonator typebe what I want if I want a louder exhuast sound with my y-pipe?

I understand better go resonator if you have a catback but in mycase if I want a sound increase I should go non-resonated if theymade one?

[crayzitalian3]

i really hate to ask this question and im sorry if this was asked before but im half asleep, what do these do exactly, and could they also be made for 4 cylis

[nurseryboy]

i really hate to ask this question and im sorry if this was asked before but im half asleep, what do these do exactly, and could they also be made for 4 cylis

The 2 downpipes for a 3.5 connect the headers to the y-pipe (headers -> downpipes -> y-pipe -> catback). Since the v6 has 2 sets of headers, there are 2 downpipes. They're also what the catalytic converters are on. (See my pic a few posts up for a general idea of what they look like. Obviously the stock ones won't look that pretty.) I'm sure the 2.5 has a (1) downpipe too, that performs the same function, but I don't know anything more about it. The general idea of having aftermarket ones made is to make them more free-flowing, hopefully providing some more horsepower.

[nurseryboy]

I'm not going to get a cat-back so would a non-resonator typebe what I want if I want a louder exhuast sound with my y-pipe?

I understand better go resonator if you have a catback but in mycase if I want a sound increase I should go non-resonated if theymade one?

I really have no idea. Since they aren't available for our cars, I'm not sure what the sound difference would be between resonated and not. I'm sure non-resonated would change the sound quite a bit, but I don't know if it would sound good or not. (My guess is it would sound good)