Okay so I've been reading the threads typing in numerous searches to really get a good understanding of exhaust. There are a few terms that are throwing me for a loop and just random questions that I have. I'm a novice and do know general maxima info to gain hp but I feel like i dont have a true understanding. So im hoping this thread will help me and others for future exhaust info.

I'm looking to see if people will help give a exhaust breakdown. If im going to do an exhaust overhaul where should i start. What components to replace in what order. I see people talking about gutting the cats but im a litttle lost because i know i need a new cat but i just found out there are three(i think i need the front). But what does gutting the cats mean and do? I heard getting an aftermarket y pipe(warspeed) but if that replaces the cats wouldnt i get a code? When replacing these exhaust components do they all need to be the same diameter? 2.5inch, 3"? B Pipes replaces the Cats in some cases? What are the best companies to go with when replacing?(or most reputable)

Okay These are just all general questions I can come up with but i think you get where im going. I just hope this thread can break down exhaust systems and how people like me should go about modding it up to get performance. ALLLLLL INSIGHT WELCOME

Oh and I know some of this is scattered throughout but Im hoping to bring it together here. A couple of these questions I know but ill be following up with general questions that will help people in the future so please bare with me. I hope this thread gets going.

Y-Pipe Header Write Up For 5.5 Gens: TunerMaxima3000
http://forums.maxima.org/5th-generat...00-2003-a.html
OBX Headers Install Links:
http://forums.maxima.org/5th-generat...n-writeup.html
http://forums.maxima.org/5th-generat...-comments.html

 

I'm in similar situation but in Canada.......

How much of a budget do you have?

 

Okay so first off, it really isnt as complex as it seems.

1) gutting the cat means to empty all the carbon deposits or whatever out of it. Its like a bunch of black chunks that are just sitting in there. It is a good short term alternative to replacing the cat. If you are going to replace the cat go ahead and buy a Fast-cat or high flow cat.

2) Yes you should always try and keep the same diameter of piping throughout the system. As a general rule, bigger diameter piping results in more power and a deeper tone.

3) Most cost effective exhaust mod would be the Y-pipe. Coupled with headers and a catback your looking between 15-30 hp gains. With the Y-pipe it could throw a code, then you just use an O2 sim or anti-fouler.

I hope this helps, RC

 

Well right now my particular situation is for me is just replacing my Catalytic Converter.

 

So if im having an issue with the cat I should just replace the stock y pipe with a warspeed y pipe? Because that eliminates all the catalytic converters right? Then just use the O2 Sims or Anti-Foulers right? BTW If i was going to a 3" Cattman further down the line should I keep that into consideration when doing the Y Pipe?

 

Run! Run! Away now!

 

Hey like I said before this thread isnt just about me. Im hoping that this thread can turn into a one stop thread where NEWBIES or experts can either GET info or GIVE info on ANY exhaust info. It's to help

 

http://forums.maxima.org/5th-generat...ics-video.html

 

Your obviously very new to this subject and still have a lot of searching to do. I will give you a brief overview but you should search because all of the knowledge is out there.

The most common place to start with out cars is with a catback. This replaces the exhaust from the rear catalytic convertor all the way back. Two of the more preferred brand names for our cars are cattman and Meagan.

The y pipe isn't as effective when it comes to horsepower gains compared to previous generations, so I wouldn't look into them.

Instead, look into headers which both front and rear precats and gain the most bolt on power for our cars. FWIW I have had obx headers on my car for 3 years and loved them. Although if you have the money to spend, cattman is a more quality option. If you decide to go this route all you will need is a dual output o2 simulator (search this term) in order to keep your engine light off. Goodluck

 

I was new and just went through all of this so I might as well help a bro out with what I've learned so far.

The air system in the car goes in this order:

Intake > Engine > Headers > Y-Pipe > Catalytic Converter > Catback (Which includes muffler at the end)

I started by adding an Intake (Injen, not the best) to get more air into the engine, then I added a bigger diameter catback (SRS, again not the best). These 2 alone made the car quicker and much louder/deeper because of the improved airflow through the larger diameter piping.

Then I replaced the Y-Pipe, and went with Warpspeed (decent).

All of these individually will add small horsepower gains, but once you have the entire system ridded of any smaller diameter piping (which chokes the whole exhaust chain) then you really start to see decent hp gains.

I still have stock headers and a stock catalytic converter which are choking my system. It's a daily driver however and I've acheived a nice sound so I dont care to go further.

 

For comparison (exhaust flow out of the cylinders):
(Stock) exhaust manifold --> pre-cats --> y-pipe --> [main] cat ----> catback
(modded) headers ---------------------> y-pipe --> hfc/test pipe --> catback

hfc = "high flow cat" aka "race cat"
test pipe = "for track use only" pipe that replaces the main cat
catback = b-pipe (resonator) --> over-axle pipe --> muffler

Corrected/more clearly explained:

 

replacing the main cat is a silly thing to do on this car, IMO.

On your car, OP, replacing the Y pipe is pretty much pointless. You will not replace the cats by replacing the Y pipe, they're separate on the 2002/2003.

If you need a pre-cat, the cheapest route is to gut them and install a non-fouler (weld into the pipe). This will 'trick' the computer into thinking the Pre-cat is still there.
Gutting = removing all the Catalyst material from the inside of it. Cat is short for Catalyst. Without the stuff inside, it's just a hollow pipe.

Or you can get HFC's to replace the stock pre-cats, but you'll still need non-foulers.

Or you can get headers, but you'll still need non-foulers.


The price jumps a few hundred dollars for each option listed. How much do you really want to spend here to fix the problem, or do you want to modify this car for power?
If you just want to fix the issue on the cheap, gut the cats and put in non-foulers.

 

Well my particular problem is that my catalytic converter has a hole and gas is getting out and sometimes you can smell it in the car. So my thing is whats the best route to go since i will eventually want to mod the whole exhaust. Would it be a big price difference just to replace the cat or should i just go ahead an and do whatever exhaust mod that replaces the catalytic converter?

 

I appreciate everyone's input thus far. Keep in mind my questions are just to get the conversation going. Anyone is welcome to add their inpit on best exhaust set-up, Best order to start in, most popular company, etc. Or just add advice.

 

In my experience right, it is better to do it right the first time, i.e. go for the performance upgrades now. It is much better to pay more up front than to do it twice, as you will most likely pay more and have more hassle with the latter. Also, I get slightly better mileage after installing headers and exhaust. Example: an increase from 23.5 to 25.0 mpg avg over 15000 mi is ~$150 (@$3.91/gal). Which is real money.

YMMV

 

Cattman Headers, Cattman Fastcat aka HFC, Cattman 3'' Exhaust most will say the BEST.

OBX Headers with a little work, plug a o2Bung and Relocate it to the right spot, 2.5in Test Pipe, Ebay Exhaust for the Piping to Stock Muffler, there is so many ways you can do it, I just bought once and was very Happy and that was with the Cattman Set Up....GL...

 

There isnt really a mod that replaces the cat at the same time as improving something else, it's a stand-alone part. There are Y-Pipes that mess with PREcats for 00-01 Maxs, but if your main Cat has a hole you might as well just throw on a new High Flow Cat right now and start the whole upgrade process. That would be the best place to start considering your existing part is already broken.

 

You have 3 catalytic converters. Which one?
If gas is coming from your exhaust you have way bigger problems than changing the exhaust.
Unless you mean exhaust gases.

 

Wow incredible point, this makes me want headers.

 

me 2!

Do you lose any torque on the bottom end with the headers or just gains across the board?

 

Do it, Tuner! You could even get longtube headers for your car
I haven't dyno'd it yet, and I have a 350Z IM, so I can't really say. But I want to say not noticeably...

 

If I buy headers, they'll be for the G35, not my winter beater

 

I just finished installing my OBX headers this morning. All I have left on that front is to extend my rear primary O2 sensor harness so I can plug the damn thing in. Other than that I have a fast cat and 3" cat back system coming from Brian as soon as he ships. I'm very excited and can't wait to hear it on the car.

 

sick dude^^ nice setup!

 

Thanks! I think it's going to be pretty awesome. In progress picture...

 

I gained all the way across the board! Couple it with Popcharger/R2C/NWP sparcers/ hi Flow cat/3" Catback and you'll b really surprised at the throttle responsive.....

 

That's what I meant (thus LTH)

 

Ahhhh gotcha. Eventually.

 

Its the front cat. the one that has an elbow. But wait if i get a high flow cat, that means ill get a code right? then i just get the foulers? um oh and which cat does the warspeed y pipe replace? like you said i dont want to do the same thing twice.

 

Think Fed Spec deletes both, and Cali Deletes the Rear one, I would get them OBX Headers and bust the o2 Sim, do thery do a Sniffer test in the ATL...

http://www.ebay.com/itm/OBX-Racing-S...bc30e6&vxp=mtr

 

^This, but under your name it says you have a 2002 "NYtoocool", if that's the case, there is no Y-Pipe that will replace ANY cat's on your car.

The only way to modify/delete the pre-cats is to:

1. Gut them
2. Replace them with HFC's (High flow cats)
3. Install Headers

 

What tuner said.

In a nutshell buy headers or replacement precats.

y pipes that rid precats are for the 3L engines

 

I see but the keyword is precats....I think ill just buy some headers...So since my front main cat is the problem though, ill buy headers and still a high flow cat to replace that main front cat?(the elbow one) or the headers will take care of that?

 

I think i figured out obviously which order ill start but in which order in general would you all start modding the exhaust? Using which company? and 2.5" or 3" set up?

 

Headers come right off the engine and replace the stock manifold and y pipe completely. They completely eliminate the pre cats.

 

Here this should help you understand

Http://forums.maxima.org/5th-generat...00-2003-a.html

 

Read. Very informative write up. I placed your link into my original post. The only thing either I haven't gotten to yet, or seen was. 2.5" Headers or 3" Headers? Would either make a difference whether I decide to get 2.5" Catback or 3" Catback?

 

lolz FTW

 

Header size is normally under 2.5, they get progressively larger as they split, this is for a reason, you want the headers smaller than the rest of the exhaust.

pick a brand not a size with headers.

 

Besides Cattman, any other Brands that you recommend? And i dont see Cattman's headers on his page? i take it i have to call for our stuff