Whtmax'01

I may have to chagne the precats, and wondering if anyone knows if this company has good precats. I have 95,000 miles so I am beyond that 80k emissions warranty.

precat

foodmanry

iTrader: (15)

From what I see in that picture it looks like that is the Y-pipe. If that is the case, then I would recommend replacing your y-pipe with an aftermarket. It is less expensive plus you get higher performance.

But...if you are getting the P0430 code changing the y-pipe will not help.

AnDyMaN

iTrader: (19)

or you can buy one from someone off the .org for like 1/4 of the price....

foodmanry

iTrader: (15)

Yup...but if he's throwing the P0430 code he needs to make sure to get the right pre-cats. He would basically need it off someone who has replaced their headers. Not sure if any of those people are willing to give up their OE piping, but worth a shot.

Whtmax'01

i have the PO420 code but i use the O2 sim to get rid of it, however i don't want to have that faulty cat and replacing with y-pipe will cause problems during inspection. Last time i had the car inspected the guy was very detailed in inspecting the exhaust of the car.

2001SE

The precats only work when the car is cold. After 15 min, you could pass inspection 30 times in a row as long as the engine is kept warm so the pre-cats wouldnt need to work. I dont think he could ever know that you have an aftermarket Y-Pipe unless the engine is cold, so he can look under your car for a week. You shouldnt worry.

Whtmax'01

There are two precats on my car, does the y-pipe get rid of only one? Anyone know which precat the y-pipe eliminates, and will I need to have two 02 simulators with a y-pipe?

frankd121

iTrader: (1)

That is correct, the y-pipe only eliminates one of the precats. There's another one in the front exhaust manifold (not sure if there's one in the back). If you get an aftermarket y-pipe, you don't need an o2 sim, only when you get headers do you need them.

foodmanry

iTrader: (15)

If you are in fact ONLY throwing a P0420 code then yes an aftermarket y-pipe will solve the issue since that will remove that pre-cat from bank 1 (rear).

I, on the other hand, am throwing a P0430 code which is bank 2 (front) and am running an aftermarket y-pipe. So my problem would be solved either with new pre-cats, or O2 simulator. I haven't figured out what I'm going to do yet.

DubbedQ45

I had my ses light pop on and I took it to the dealer and they said it dropped a p0420. They want $950 for everything. That’s some bull! They said aftermarket may be cheaper so I saw your thread. I’m more of an audio junkie than engine junkie so I’m a bit less knowledgeable about motors.

From all the searching I have been doing on here people say that the Y pipe will give a little kick(all for that) but also give you a bit of increased exhaust sound(not too sure how I feel about that). Anyway, I had a couple questions.

With the aftermarket Y does it hurt fuel economy? I travel about 150 miles a day for work and loosing good highway fuel economy does add up for me in the long run.

Also, I have a 01 AE I know they have a small difference with exhaust that a normal 01. Does that benefit or hurt?

If the Y pipe is replaced is there anything else that needs to be replaced or added? I don’t want to put a Cattman Y pipe in and find out that its killing my car because I don’t have an intake or aftermarket cat-back system.

How do I tell if I need the federal or Cali spec Y pipe? I’m in the Mass/NH. I saw a diagram but that didn’t help me out at all. I know the Cali spec cars can be anywhere so I just was curious if there is a better way to find out before I make a purchase.

Thanks in advance.

foodmanry

iTrader: (15)

It will actually improve your MPG slightly, unless of course you leadfoot it more due to the increased performance.

Enginer and exhaust systems are the same between 00, 01, and AE edition. IT will not affect it.

No..the only other thing that you would want to replace are the exhaust gaskets and crush rings/washers.

Open up the hood..look at the engine bay facing it from the front. You will see a line of plugs just in the front part of the engine on the top behind the radiator. If you have 4 plugs then you are CA spec, if you have 3 then you are fed spec.

upstatemax

iTrader: (15)

Not entirely true, 00's have an EGR while 01-03 do not.

00MAXI

You can solve the Low efficiency P0430 Bank 2 code with an O2 sim???? That's way cheaper than buying precats! Right?

Please enlighten me...

Why would an 02 sim solve this?

Is it because the 02 sensor "senses" a dirty precat and records it as a CEL?

So is the flow of the exhaust affected by not replacing the precat?

Do I lose horsepower or gas mileage?

Puppetmaster

iTrader: (48)

All 2001s are Cali spec.

http://forums.maxima.org/showthread....935#post275935

Whtmax'01

OK, I realized that when we put in a O2 sim it solves our headaches when passing inspection, but doesnt P0420 mean that the precat is not working right and thus doesnt that mean that there is a kind of choke point in that area of exhaust?

00MAXI

You can solve the Low efficiency P0430 Bank 2 code with an O2 sim???? That's way cheaper than buying precats! Right?

Please enlighten me...

Why would an 02 sim solve this?

Is it because the 02 sensor "senses" a dirty precat and records it as a CEL?

So is the flow of the exhaust affected by not replacing the precat?

Do I lose horsepower or gas mileage?

upstatemax

iTrader: (15)

all the O2 sim does is give a false possitive reading to your ECU so it thinks that your Pre-cats are working.

The sim just sends a constant I think 12v signal to the ECU and your car thinks it is fine...

EDIT: and yes a clogged cat can effect your perfomance, I would just get an aftermarket y-pipe to eliminate the precats and simulate the secondary O2 sensors...

Puppetmaster

iTrader: (48)

But if the car is Cali spec, the y-pipe wouldn't replace the Bank 2 pre-cat. In which case, the options would then be:

a) get a new OEM pre-cat
b) punch out the existing pre-cat (probably needs O2 sim)
c) do a Fed spec conversion with Fed manifold (O2 sim required)
d) aftermarket headers

00MAXI

Sorry I should have clarified. I have a Cattman Y-pipe. The P0430 is Bank 2 Front pre-cat. But even so if this front pre-cat has low efficiency then performance could be hindered. CORRECT?



Just read the post after yours. My option is pretty much getting a new front pre-cat. I don't have the know how or tools to punch out the pre-cat and stick a 02 sim in.

upstatemax

iTrader: (15)

If you have a 2000 Cali spec with a cattman y-pipe, as I remember you should not even have a pre-cat left... If I remember from my header install, both pre-cats are in the y-pipe.

Puppetmaster

iTrader: (48)

Are ya positive about that? I guess technically, the 00 Cali specs have the front pre-cat between the y-pipe and manifold. Its on the bent part that bridges the y-pipe to the manifold.



I think this diagram (from the O2 sensor TSB) is pretty accurate for 00-01 Cali specs, but not for 02-03 because the rear pre-cat is not on the y-pipe and that isn't reflected here.

upstatemax

iTrader: (15)

Man I really wish I took pics from the header install. I am almost positive both pre-cats were in the y-pipe... I am trying to call my brother who helped me with the install to see what he remembers...

Puppetmaster

iTrader: (48)

Sounds good...

Now where is Irish44postwhoreJ when ya need him... he replaced his 00 Cali spec y-pipe with a Cattman y-pipe recently and should know too....

Puppetmaster

iTrader: (48)

One more piece of evidence I found... Desert Pearl's Fed spec conversion of his Cali spec 00:

http://www.desertpearlmax2.homestead.com/Fed_YPipe.html

You can clearly see that the front pre-cat is attached to the front manifold:



Left - Fed manifold with extension Right - Cali manifold with pre-cat