[phrog man]

Where do the 3 exhaust Flange gaskets for?

 

[RacerXXL]

Where do the 3 exhaust Flange gaskets for?

They are for the Y pipe.

 

[phrog man]

so headers to cats get a crushwasher and a 3 bolt gasket each?

 

[phrog man]

3 EX Flange Gaskets (2 Bolt)

why a 2 bolt flange gasket if the headers to cats are a three bolt pattern?

 

[RacerXXL]

so headers to cats get a crushwasher and a 3 bolt gasket each?

No I misunderstood you above and edited to fix it ..... sorry. There is no 3 bolt flange gasket it is just a crush washer.

3 EX Flange Gaskets (2 Bolt)

why a 2 bolt flange gasket if the headers to cats are a three bolt pattern?

Because you unbolt the Y pipe to get it out of the way and make room to remove the down tubes. Being a Y pipe it has 3 pipes and connection points all with 2 bolt flanges....so 3 gaskets.

 

[phrog man]

got it thanks for editing.

 

[mikeman1985]

Awesome write up.

I have the same cracked manifold problem on my 01 and have been toying with getting the headers and cel eliminators from 4x4 parts.

I'm curious though, will the cel eliminators cause any problems? My concern would be anything that would hurt the already bad fuel economy I get... My x has 4 cats could I just relocate the back o2 sensors to after the secondary cats, or just go with the cel eliminators?

Did you notice any change in fuel economy? I'm also looking at this to maybe help improve my 15city/18highway that i'm getting.

Next after this would be prolly a nismo cat back. I hate the stock y-pipe, it's really more like a t-pipe, horrible.

 

[Mirage]

Awesome write up.

I have the same cracked manifold problem on my 01 and have been toying with getting the headers and cel eliminators from 4x4 parts.

I'm curious though, will the cel eliminators cause any problems? My concern would be anything that would hurt the already bad fuel economy I get... My x has 4 cats could I just relocate the back o2 sensors to after the secondary cats, or just go with the cel eliminators?

Did you notice any change in fuel economy? I'm also looking at this to maybe help improve my 15city/18highway that i'm getting.

Next after this would be prolly a nismo cat back. I hate the stock y-pipe, it's really more like a t-pipe, horrible.

Definitely worth it, I picked up a couple mpg's, though it was down because of the cracked manifolds.

The CEL eliminators are for the back o2 sensors, not the front ones, the front o2's go back into the headers just the like stock, the back ones are the ones that make sure the cats are working. I reccomend http://bigdaddiesgarage.com/angled-cel-fix.html for the cel eliminators.

 

[girene]

After being out of the States for awhile I'm back and finally buttoning down to do this project. I hope to get the parts on order in a couple weeks and all ready have some friends willing to help me out.

I'll probably need it.

 

[RacerXXL]

After being out of the States for awhile I'm back and finally buttoning down to do this project. I hope to get the parts on order in a couple weeks and all ready have some friends willing to help me out.

I'll probably need it.

Welcome home and glad you are getting ready to do this. One thing I would do different....well two. First the Thorley's are cheaper and I've seen both so I would probably order the Thorley's. Two if you end up with a custom downtube assembly using a three bolt flange and traditional gasket to connect the downtube to the header I would use these instead of the standard paper type gaskets.

My paper gaskets lasted two years and blew out but these look like they will last much longer.

 

[girene]

Well it'll be interesting. The Thorleys have been sitting in my cargo space for almost three years now. I got them right before I trucked across the nation the first time.

However it just occurred to me that I have a Cali X with the double sets (which I think just the first set is removed). Fine and dandy because its registered in IL now (and saves me a boatload of money on license renewal in the process).

But, I renewed my base decal (old one expired July 2010), and its good until Sept 2013 which is maybe a month before I get out. Which means I have to renew my base decal right before I get out. Which sucks, because anything older than 6 years, even if registered out of state needs a smog. My last two the X ran pretty damn clean, so it'd be interesting to see how it'll turn out with one set of cats out.

I would like to figure out down the road when I get home where I can get some stuff fab'd up to make the 2nd set larger downpipes to match the catback.

 

[girene]

Update:
With a long weekend thankfully given to us by the CO, I'm looking at starting to tackle this project today.

Wish me luck.

Another Update:
After much knuckle dragging and such I have them in! 8 hours of work but I ran out of time as the hobby center closed but all I have to do is tighten up the exhaust system bolts I dropped in and threaded, zip tie the O2 lines away from the exhaust, and start it and leak check it, retorque the mount bolts, put the wheels on and roll out like a boss.

I will offer my perspective on a Cali-cat'd 2001 SE 4x2 and DT headers:

One: Scruffy 2nd's the PB Blaster. I only got about 5 hours before I started the job in, but it saved me arse!
Two: I found it easier to bust down the Y-pipe, remove the connecting pipe on the driver's side (fwd of the Y-pipe, connects to the 2nd Cat), Then disconnect the first cat from the manifold. This allowed me to pull the 1st cat, 2nd cat (w/ downpipe) back to get at all three of the 1st to 2nd cat nuts. With a breaker bar and a bit of airframer strength they all came out.
Three: A long long extension is boss for getting the manifold nuts off/on.
Four: A 8-10 incher is great for the working in both sides.
Five: Did I mention a breaker bar?
Six: My Y-pipe to 2nd cat & down pipe had one nut that I just ended up rounding off. I didn't have cutting implements to get at it, and had no clue where to go from there. So I gave up and did the Driver's Side first.
Seven: I found the Driver's Side super easy.
Eight: Many body mounted heat shields were removed because I hated them. The Driver's side has one that will block the O2 sensor. The Passenger side has one that will be in the way when it comes to removing the 1st cat bolts (the outboard side one is "hidden" behind the heat shield), a proper application of the airframer's motto of "hammer, screwdriver" solved that problem and after getting everything apart I removed that heatshield as well (it was beat all to hell).
Nine: Passenger side is easier to get at for removal of the manifold.
Ten: Order extra manifold nuts. Because DT provides the header to 2nd cat (or downpipe) bolts & nuts you may turn out with some more 14mm nuts, IF the studs don't come out with it as one piece.
Eleven: You may as well right off any nuts that turn out with the studs because I dethreaded about 75% of the ones I put in a vice and turned. They are stuck for a reason. PBB couldn't save me here.
Twelve: I only have my PML on the front and back and got everything out with a little work. You will have to disconnect EVERYTHING and then remove the manifolds but it will all come out the wheel well holes.
Thirteen: Speaking of which, those damn tire wall backers and the plastic clip things are cheap and horrid. Mine are now ruined and gone and I don't want to deal with them.
Fourteen: You will need a wrench to get many of the manifold nuts back onto the headers, no how far backed out I had them, many cases there wasn't enough room for a socket because the header tubes were in the way. I just German Torque'd them (Gut n' Tight).
Fifteen: Those damn O2 sensor adapters, I PB Blasted the crap out of them, I used a wrench and vice, and the driver's side was horrible. It wouldn't come out. Much "coaxing" was involved and I may have beat the sensor up a little bit.
Sixteen: See in the pictures. But I didn't have a driver's side plug, where it should have been was a solid cast piece that appeared like one, but it wasn't even hollowed out to it internally. I have to ghetto it until I get a replacement.
Seventeen: Back to number Six. It took a bit of work but I took the mounts for where the y-pipe meets that 2nd cat and down tube and removed the nuts holding the bracket on. I also pipped the forward mounting bracket on my NISMO muffler and dropped it down to give the y-pipe more backup room. I then popped the 1st cat off of the manifold. This allowed me some play room to get a medium length extension in there to get at the nuts holding the 1st cat to the 2nd cat. (and the heat shield beating). After getting that all apart, I had a bit of room to drop it out of the way, pop off the manifold, pull it out through the wheel well hole, and then with the forward space clear, pull the 1st cat out. So even with that whole assembly together I could still get it to work. So that bolt will just have to stay rounded off until I need to get into the exhaust for one reason or another.
Eighteen: No matter how I route them, some of the O2 cables are just damn short. I think with a little work I can move them, but they seem to be in okay spots. Zipties HO!
Nineteen: Did I forget anything? Anyways these are just my "notes" to help out anyone else with a similar setup with my experience of doing this job. It started out daunting and horrible, but I got the passenger side done lickety-split and probably only have an hour of real work left. Too bad the hobby shop closed on me.


On to the pictures!

My ghetto ass lugnut, bolt, and sealant job to make up for a plug that is supposed to be on the original manifold but is not. OH well.

I beat the living shit out of this O2 sensor, won't be surprised if it throws codes and check engine lights. Also it has about 1 1/2 threads left, so it should get replaced anyways.

Driver's Side done (forgot to take a pass side, will do a more thorough photo op tomorrow to show how I have everything setup and update this post.)

Driver's side with a big ol' crack, just like I thought.

And a twin in the passenger side!

Also even with work gloves (which I forgot about in the first 2-3 hours of work, I managed to crush a pinkie (gloves on), scrape a finger real good (w/o gloves), and then cut my cuticle on another finger (again w/o the gloves). Not a big deal... but not when I still have about 5 hours of grease, oil, PB Blaster, and brake cleaner to rub into those wounds... Mmmmm feels gooood.

Will either update this post or just post another update when I get some more shots and finish up the task. I have a feeling I'm still going to through some.

Damn. I can't get the plug for the Driver's side by itself. This might stink. Gonna have to check the dealerships

 

[Cap927-Boston]

Wise I noticed this post when I tackled mine last week, got the same code pretty much around 5 miles later and reset ECU by disconnecting the MAF sensor.. so far 3 miles later and no light yet. Will see what happens the rest of the week. Thanks for the post, even thou it is after my nightmare, it is still very helpful.

 

[RacerXXL]

Damn. I can't get the plug for the Driver's side by itself. This might stink. Gonna have to check the dealerships

Mirage came up with 14052-21R00 as the part number for the plug for the EGR.

 

[xtacular]

^I found mine at a local hardware store called Parkrose Hardware, it might be worth calling around.

 

[DblBlack26]

So you guys are all still passing emissions with 2/4 cats removed?

 

[xtacular]

Personally mine doesn't get sniffed. Actually doesn't even get a visual inspection. It varies by state and county.

 

[Legit_Keeper]

Where can I find the short studs? I've looked around and can't seem to find them. Thanks in advance!

 

[RacerXXL]

Where can I find the short studs? I've looked around and can't seem to find them. Thanks in advance!

https://www.4x4parts.com/nissan/upper-exhaust-studs-p-4882.html

 

[Legit_Keeper]

Thanks Racer! And while I have your attention... I'd love for you to check out my newest thread so I can get your opinion on some things.

http://www.clubxterra.org/forums/showthread.php?t=88234