cmax1

I caught that crap today...

Too bad i live in the midwest and my bolts are very rusted..







Looks like i have to cut those bolts off the y pipe that comes down from the rear cat because i spun two of them.. Also, my grinder cant fit in that tight place so do they make a cutting wheel that can fit in that tight area? Thanks..

NmexMAX

iTrader: (22)

Why are you doing this?





























IB_becauseracecar

cmax1

Looking to improve gas mileage with the hopes of keeping the most likely clogged cats from killing the engine.

OnOiShNo0dl3Z

iTrader: (2)

Do you have a p0420 or p0430 or any other reason to believe it's clogged?

Rochester

iTrader: (3)

That made me laugh.

Gutting the cats on a 10 year old car is the in-thing right now, NmexMAX. All the kids are doing it...

...toocheaptogetheaders.

Clashez

iTrader: (5)

gutted pre cats and a warpspeed y pipe would make some good power on the cheap.......

cmax1

Its not really about power, just want to get rid of the precats.. I searched around and seen many benefits in doing this, but my main goal is the better gas mileage(maybe).. BTW, any suggestions on the cutting of the bolts? Would a angle grinder get in there to shave off the bolts?

Cant_Get_Ryte

iTrader: (52)

you can put a too small socket on and utilize a ratchet. basically an old trick for when you lose your wheel lock key. basically the 14mm, beat a 133 with a hammer. or you can use PB Blaster to loosen it hopefully. Only other way would be an air hammer. I have one in the garage lol, but you aint local lol

cmax1

Air hammer or angle grinder? Which would work best for the three bolts that connects to the rear cat? I just want to have the best angle at those bolts so i dont mess up the y pipe itself..

Rods03Max619

iTrader: (5)

How much Clash, you do them Dynos yet....

cmax1

pieces of the mesh missing from the front cat..



is it possible that the chunks pulverized and went through the cat, or did it go into the engine?

cmax1

if while doing this project and you strip the threads that hold the oxygen sensor to the b piple, how do you get the anti fowler sleve to hold onto the b pipe..

Edward Lee

iTrader: (3)

dont gut your cats

cmax1

tooooooooo late!!!!! they are already gutted but i stripped the secondary 02 sensor coming off the rear cat... how do i get past that?

oms

Did you end up using a sawzall to remove those bolts?

As for the threads, if the oxygen sensor threads are mangled you can use a universal thread repair tool (you will need to measure pitch etc of the thread). If it's the read cat hole you need something like a Helicoil kit.

cmax1

I used the sawzall on three bolts for the rear cat (firewall side) and for the main cat.. Bolts where too rusted to even heat loose..

Helicoil kit? I will look into that. Thanks..

cmax1

On the rear precat, is there a ring that fits where i have the screw driver pointed? I think it is but i cant seem to find it. If there is a ring that belongs in the location can any provide the part number.. thanks

nelledge

iTrader: (6)

There is a ring in that location, but I don't know the part # off the top of my head.

It should be 20691 8J100. It's depicted as a flat gasket in the parts catalog, but it should be a ring. Your local dealer will probably have it in stock.

cmax1

Thanks for the response... I guess i will have to go to the dealer and get screwed because i would hate to order a gasket and it doesnt fit.. My stealership wanted to charge me $13 for the gasket that goes between the main cat and the stock y pipe..

036mtmax

iTrader: (11)

I re-used my old one with no leaks but i also gutted the cats on a whim so i didn't have gaskets but i might have just been lucky.I looked on courtesy parts.com and couldn't find that ring but i guess if you brought your pre-cat in to the stealership's parts dept and show them the missing gasket they may be able to find it for you.The diagram of the a33b exhaust on courtesy's site isn't right

036mtmax

iTrader: (11)

cross threaded is better than not threaded

cmax1

Looks like i may have to.. They dont even me b4 they do me. $20 ring gasket fo sure..

036mtmax

iTrader: (11)

lmfao, the least they could do is give you a

1991Maxima1991

iTrader: (3)

i baught my "crush rings" when i did my cats from napa.... There is actually 2 crush rings total 1 on the y pipe section and one on the rear cat....they costt me about 4 dollars a peice....they also had the manifold gaskets for 14 bucks and the rear main cat gaskets for around 4 a peice also...if your thinking about going that route then i might be able to find the wrapper that the gaskets came in for the part #'s

o and btw i also stripped the threads out of my 02 sensor getting it off...i played hell trying to get the sensor to screw into the anti fouler and then getting that whole thing into the stripped out y pipe...so i got it in as much as possible and jb welded around all the threads...its on there pretty damn tight but only problem is when i was trying to get the sensor off i some how i think damaged it and i heard rattling inside of the sensor...and i am throwing a ses light right now i believe its the p0430...

spock

iTrader: (5)

That would be extra. Minimum 1/2 hr labour.

cmax1

if u can find the part# for the ring that is between the manifold and cat..

for this i may take the y pipe to a exhaust shop and see if they can weld a bong into it..

1991Maxima1991

iTrader: (3)

wow crazy the one wrapper i found i believe IS the correct one lolol, part number is 31354

cmax1

Well I finally got everything back together and figured i would post my personal results of gutting the precats..

With everything stock, on start up the car is noticeably louder than before. It has a gurgle that wasnt there before, but not raspy like some have posted they experienced.. Now the drive is when things get interesting.. First thing I noticed is a "moan" at around 2-3k rpm which turns into a "wooshing" sound as you lay into the trottle.. The wooshing is coming from the gutted precats i assume due to the large hollowed area.

As far as power gains is cocerned. I dont know if you would call it a gain or a power recovery, but it is noticeably quicker than before and pulls hard as heak all the way to redline.. It actually gets the 'slip' light going when punching it to redline in 2nd , just overall better in all rpm ranges to me than before.. I think i have to realign the y pipe to the rear cat because i can hear a rushing sound at wot in that area.

Im using the anti-foulers for my down stream sensors and the only code im getting is a p0057, one of codes i had before the job. I had a p0057 p0037 and p0138 (sensor on the ubend in the ypipe) and i replaced sensor so now just the lonely p0057. If anyone can help out would be most appreciated.

Overall i love the mod, just a lil too loud for my taste inside of the car...

Rochester

iTrader: (3)

IDK about any "wooshing" sound, but overall your assessment seems about right.

Personally, I like the new, deeper rumble inside the car when at idle.

cmax1

I love that part.. Has a real nice tone to it.. I need to tighten up my exhuast pipe more because its real unstable from the center section back and i think that is causing some resonance.. Real strong mod no the less.. I guess this is how the mod snowball effect starts out?

Ghost_54

iTrader: (13)

This what I found using a google search as you said you were using anti fowlers I found it odd that your still getting a O2 sensor code.

P0057 NISSAN Description
Oxygen Sensors (O2S) or Heated Oxygen Sensors (HO2S) need to reach a minimum operating temperature of 750 degrees F to produce an accurate voltage signal. The faster the heated oxygen sensor reaches that temperature the faster the sensor will start sending an accurate signal to the Engine Control Module (ECM).

In order to achieve the require temperature, a heater element is included inside the heated oxygen sensor. The ECM controls the heated oxygen sensor heater element based on signals from the engine coolant temperature and engine load. The ECM controls the heater element circuit by allowing current flow to ground.

The ECM monitors the voltage signal received through the heater element circuit and determines the state of the circuit by comparing the voltage detected with the factory specifications.




Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
Possible causes
- Heated Oxygen Sensor (H2OS) Bank 2 Sensor 2 circuit open shorted to ground
- Heated Oxygen Sensor (H2OS) Bank 2 Sensor 2 circuit poor electrical connection
- Faulty Heated Oxygen Sensor (H2OS) Bank 2 Sensor 2 circuit
- Heated Oxygen Sensor (H2OS) Bank 2 Sensor 2 circuit fuse
- Faulty Engine Control Module (ECM)
When is the code detected?
The P0057 is set when the ECM detects an excessively low voltage through the heated oxygen sensor heater circuit
Tech notes
The code means that there is a problem with the heater element circuit of the heated oxygen sensor. Water getting inside the heated oxygen sensor connector can caused the heated oxygen sensor fuse to blow, which is a very common problem for this type codes. Before replacing the sensor, check for the condition of the heated oxygen sensor fuse and connectors.

The tech note seems to be a good place to start, check to make sure you don't have water getting into the sensor and of course check any possible blown fuses. The other note of interest would be the engines coolant temperature.

cmax1

Thanks ghost.. I'll look into that tomorrow..

svezarov

cmax1, can you please give a more detailed explanation on how did you remove the 6 nuts that attach the y-pipe to the manifold and the 2 bolts that attach it to the catalytic converter. Was any drilling and re-tapping involved as well. My car is in it's 16th year in Ontario and my y-pipe is almost severed at the flex section, so I have to change it soon. I looked at it last night and my bolts all look like yours - can't even see any thread on them. I need to know if you cut the studs to the manifold, did you have enough space for the sawzall (especially at the rear manifold) and if you cut them, how do you attach the pipe to the manifold after that. Please explain in detail.

Thanks,
Tony

ivey_usmc

Im thinking about gutting mine too but I don't want it real loud. Post a sound clip if you can.

cmax1

For my car the three bolts that hold the y pipe to the front precat came off easy because i used a impact gun.. For the rear cat i had to use a sawzall on two of the bolts, but ran into a problem with one of the nuts that sits in between the y pipe.. What i ended up doing with the rear cat was removing the precat from the manifold attached to they y pipe.. You do have to bend the rear precat heat shields to get the lower bolts out..

Once every thing is out you can use a pipe wrench to remove the damaged bolts from the pre and rear cat then replace with store bought nuts and bolts...

Ivy usmc, i will post a clip over the weekend for you...

Brl24

It's not loud at all, if you still have a main cat and stock muffler, it will barely change. I did a Cattman y aswell an the unequal length caused a bit of a rumble at idle and when down revving, besides that it sounds mostly stock still