Has anyone gut the first cats on the manifolds?

[CorbinM56x]

I've got a tic over 134,000 miles on my M56x and pulled a code P0420 which is the catalyst below threshold thing! I bought a bottle of cataclean and followed the directions. To my surprise the SES light went out within 20 miles, and remains off! But I'm sure it's not a permanent fix! And I've heard that if the manifold cats go bad it can be sucked back into the rear cylinders on both banks!? Really don't want to pull the motor and spend 700 a piece for both cats!! Wonder why I can't just take the Y pipe off and gut them?? Anyone ever do it?

[armybrat]

Only problem with gutting the primary cats on the V8 is that most, if not all states, require annual emissions testing. It's not an option for a daily driver if it's required to get your tags renewed. They say you can run your car WOT a few times before taking it in (if you do delete your cats) and it will pass, but then there's the whole issue with flagging the A/F and O2 sensors. The V6 has the luxury of header style manifolds with bolt on cats and no secondary cats on the Y-pipe...if only the V8 was that way

[CorbinM56x]

Luckily I live in Michigan!! No annual DOT emissions test!! So I'm going to give it a go while I put my new exhaust on!! Worst case is my ses light will be on!

[EdBwoy]

Yeah, almost guaranteed that the light will come on, but if you don't mind it, you'll be fine.

I know the part numbers are different, but I am curious as to how those manifolds compare with the qx56 and new armada ones, physically. They cost the same, except the Armada ones are less than $300.
700 bucks sounds like highway robbery but Lord knows I do everything to avoid seeing warning lights on my dash. Tough call for me

Edit to add links:
Exhaust manifold
1. link to 2011 M56 catalog
2. link to 2012 QX56 catalog
3. link to 2017 Armada catalog

[CorbinM56x]

I'll be looking into those manifolds!! I'm guessing the exhaust port configuration maybe different! But worth looking into!! Thank you!! But regardless I think you may still have to pull the motor to replace them!! Great design Infiniti!!!

[EdBwoy]

I looked into it a little more, because in my experience Nissan tries to change as little physically as possible. The Armada makes a little less power/ torque on paper, and I don't know how accurate that is - whether for marketing to Qx56 shoppers or if they really detuned the Nissan emblem. Anyway, I was curious about the heads and how different they would have been, so here are links to them. Part numbers are still different, with Armada prices much lower.

1. 2011 m56 heads in here
2. 2012 qx56 heads within
3. click for 2017 Armada heads n stuff

Back in 2005 the Armada and QX56 both shared part #s 14002-7S01C and 14002-7S00C for their exhaust manifolds, and 11040-7S001 and 11090-7S001 for their cylinder heads, although once again the Armada was rated lower on paper. . See where I was going with this?

[armybrat]

I'll be looking into those manifolds!! I'm guessing the exhaust port configuration maybe different! But worth looking into!! Thank you!! But regardless I think you may still have to pull the motor to replace them!! Great design Infiniti!!!

Yep AWD requires pulling motor for both manifolds. RWD you can replace the passenger side manifold without pulling motor. Yeah not very maintenance friendly.

[DFW2011M56S]

I'll be looking into those manifolds!! I'm guessing the exhaust port configuration maybe different! But worth looking into!! Thank you!! But regardless I think you may still have to pull the motor to replace them!! Great design Infiniti!!!

The truck manifolds are complrtely different. Our cars essentially have tri-y shorty headers before the headers.

My car practically gutted the cats itself. I removed what was left of the cores with am air hammer and and chisel. Disabled P0420 and P0430 with Uprev. The car passed my OBD2 test in Texas without issue.

[knelson]

I've got a tic over 134,000 miles on my M56x and pulled a code P0420 which is the catalyst below threshold thing! I bought a bottle of cataclean and followed the directions. To my surprise the SES light went out within 20 miles, and remains off! But I'm sure it's not a permanent fix! And I've heard that if the manifold cats go bad it can be sucked back into the rear cylinders on both banks!? Really don't want to pull the motor and spend 700 a piece for both cats!! Wonder why I can't just take the Y pipe off and gut them?? Anyone ever do it?

Is cataclean a product we should run to possibly lengthen the life of the cats? Meaning to run it at 65K or 85K miles, etc.

[DFW2011M56S]

I've got a tic over 134,000 miles on my M56x and pulled a code P0420 which is the catalyst below threshold thing! I bought a bottle of cataclean and followed the directions. To my surprise the SES light went out within 20 miles, and remains off! But I'm sure it's not a permanent fix! And I've heard that if the manifold cats go bad it can be sucked back into the rear cylinders on both banks!? Really don't want to pull the motor and spend 700 a piece for both cats!! Wonder why I can't just take the Y pipe off and gut them?? Anyone ever do it?

Is cataclean a product we should run to possibly lengthen the life of the cats? Meaning to run it at 65K or 85K miles, etc.

Would not have helped I feel in my case. The catalyst core simply melted away.

[CorbinM56x]

I believe cataclean must work by reducing hydrocarbons, therefore tricking the O2 sensors thinking the catalyst is functioning properly!! So to me it's a mask!! And don't trust it at all!! Also I think the main reason these cats fail is from burning oil! My winter vehicle a 2005 Toyota 4Runner sport also had a cat go bad due to a small head gasket leak. Catalyst don't like coolant either!! But that was many years ago and still haven't fixed the head gasket!! Runs great to this day!! Now by design Nissan may have made a motor that burns 1 to 2 quarts of oil between changes because of no fuel going over the intake valves!? Maybe to help with lubracation of the seats!! Not really sure on that! But my engine uses oil!!! You can't see it or smell it but she drinks!! Usually 1 to 2 quarts between changes!! But that's me driving like I stole it!! In which I did for $10,000!!! So my plan is to do exactly what DFW did and remove said cats and Uprev to emulate the O2 sensors!! I don't like the fact that Nissan can make an engine that rocks and also drinks oil!! Most importantly on a $70,000 dollar luxury sports sedan!! Just my 2cents!!

[armybrat]

DI engine blows excess oil through the PCV valves. Catch cans will trap some but not all of it.

[CorbinM56x]

I had one on my 89 supra with a 1jz and a 60-1 turbo on it pushing 18psi!! Only had to empty it maybe once every other oil change!! And that was at 3,000 miles! I did notice on the M that immediately after oil changes maybe like 500 miles or so it looked very dark!! Is this also common on DI motors!?

[armybrat]

I had one on my 89 supra with a 1jz and a 60-1 turbo on it pushing 18psi!! Only had to empty it maybe once every other oil change!! And that was at 3,000 miles! I did notice on the M that immediately after oil changes maybe like 500 miles or so it looked very dark!! Is this also common on DI motors!?

Yep, mainly DI engines for valve guide lubrication...it's normal to use some oil. The 5.6 seems to blow excess oil though, IMHO. I empty both of my cans every 1000 miles, close to 1/3 cup. The last 1000 mile pic I posted was after a 5W30 Mobil 1 oil change. It looked darker than it was.
That's not counting normal blowing by; just excess. What I trap is based on my driving pattern, which is a daily Mon - Fri 50 mile round trip commute to work, mostly highway mileage, normal to slightly aggressive driving pattern...very little redlines or WOT's. If you race a lot, multiple WOT's/redlines, etc. then you will trap more oil.

[EdBwoy]

...
The truck manifolds are complrtely different. Our cars essentially have tri-y shorty headers before the headers.
...

Thanks DFW. Might you have pics of the truck manifolds by chance?
Despite the style difference, are the head-to Ypipe dimensions any close between vehicles?

[DFW2011M56S]

...
The truck manifolds are complrtely different. Our cars essentially have tri-y shorty headers before the headers.
...

Thanks DFW. Might you have pics of the truck manifolds by chance?
Despite the style difference, are the head-to Ypipe dimensions any close between vehicles?

Not even close. The cars tuck in much tighter to the transmission than the trucks. In fact they bolt to a brace that ties them into the engine and trans near the bellhousing.

[DFW2011M56S]

I believe cataclean must work by reducing hydrocarbons, therefore tricking the O2 sensors thinking the catalyst is functioning properly!! So to me it's a mask!! And don't trust it at all!! Also I think the main reason these cats fail is from burning oil! My winter vehicle a 2005 Toyota 4Runner sport also had a cat go bad due to a small head gasket leak. Catalyst don't like coolant either!! But that was many years ago and still haven't fixed the head gasket!! Runs great to this day!! Now by design Nissan may have made a motor that burns 1 to 2 quarts of oil between changes because of no fuel going over the intake valves!? Maybe to help with lubracation of the seats!! Not really sure on that! But my engine uses oil!!! You can't see it or smell it but she drinks!! Usually 1 to 2 quarts between changes!! But that's me driving like I stole it!! In which I did for $10,000!!! So my plan is to do exactly what DFW did and remove said cats and Uprev to emulate the O2 sensors!! I don't like the fact that Nissan can make an engine that rocks and also drinks oil!! Most importantly on a $70,000 dollar luxury sports sedan!! Just my 2cents!!

It is a VK56 thing all together. Both of my Titan VK56DEs used just as much oil and 90% of it was getting carried through the PCV valves.

[CorbinM56x]

Someone needs to make some aftermarket ones!!! I would think there would be a decent market for them!!

[CorbinM56x]

I'll fab up a catch can!! One or two? Which would be easier and more cost effective?

[EdBwoy]

...Not even close. The cars tuck in much tighter to the transmission than the trucks. In fact they bolt to a brace that ties them into the engine and trans near the bellhousing.

Well, there goes that hope. Thanks for the info

[armybrat]

I'll fab up a catch can!! One or two? Which would be easier and more cost effective?

There are several styles on Ebay, Amazon, etc. No need to fab one unless you just want to. They range from $20 for a plain jane trap to $200 for a machined diffuser/filter type that you can take apart. I found mine on Ebay. Since the 5.6 has a dual throttle body intake with two PCV valves, I opted to go with 2 cans. I posted a thread if you scroll down the forum. Yeah I paid a little more but I liked the style and ease of maintenance, plus I was able to use the Camaro mounting brackets to mount them to the back firewall.

[DFW2011M56S]

I'll fab up a catch can!! One or two? Which would be easier and more cost effective?

There are several styles on Ebay, Amazon, etc. No need to fab one unless you just want to. They range from $20 for a plain jane trap to $200 for a machined diffuser/filter type that you can take apart. I found mine on Ebay. Since the 5.6 has a dual throttle body intake with two PCV valves, I opted to go with 2 cans. I posted a thread if you scroll down the forum. Yeah I paid a little more but I liked the style and ease of maintenance, plus I was able to use the Camaro mounting brackets to mount them to the back firewall.

I have thought about moving the PCV valves myself. Because the VQ V6 is so commonly force inducted they make a fitting that screws in place of the PCV valve in the cover and converts to AN line. I have considered running both into a seperator filter and running a single larger inline PCV valve T'd into the stock intake manifold fittings. I feel bigger fittings and tubing with lower velocity may pull less oil.

[DFW2011M56S]

https://www.projectimport.com/store/vq3 ... n-fitting/

[DFW2011M56S]

I have actually been tempted to talk with someone at T1 and see if I could get just their seperator and adapt it over.

http://www.gtrlife.com/forums/topic/890 ... rator-kit/

[armybrat]

I have thought about moving the PCV valves myself. Because the VQ V6 is so commonly force inducted they make a fitting that screws in place of the PCV valve in the cover and converts to AN line. I have considered running both into a seperator filter and running a single larger inline PCV valve T'd into the stock intake manifold fittings. I feel bigger fittings and tubing with lower velocity may pull less oil.

I looked at the GT-R kit link you posted. Looks like a sweet rig! It's already set up for a dual intake, plus it has the check valve built in for drainage. I like the oil dipstick mod for the drain hose. I would use the AOS as intended, instead of teeing into one valve. The third inlet port would have to be plugged (GT-R had a PCV valve at the rear of the block in addition to the turbo ports), a custom bracket would have to be made for mounting, the 8AN hoses would have to be modified to fit the M56 intake and PCV valves, and the drain line would have to be tied into the crankcase or oil pan somehow for truly maintenance free application. The M56 PCV valves looks identical to the GT-R one (same outlet diameter) so I feel that they should be adequate.

With that said, I'll probably stick with what I have. For my driving pattern, I'm capturing excess oil with my set up, just have to find a way to tie the drain lines in so that I don't have to keep draining it out manually. I am curious if they would sell the separator by itself though. If the price is reasonable I may jump on it just for the check valve and dual intake set up. I can get hoses and fittings no problem. Thanks for sharing!