Stock Cat Mod

2012z · 09-30-2014, 07:50 PM

Ok, so I am going to ask the question... On the 370z the stock cats have two cells...one which is monitored buy the a/f sensor and rear 02 sensor..after that there is a cell I would refer to as a clean up cell... has anyone removed this? any gains noticed? obviously u would not get a MIL cause its not monitored.. just curious... the main stock cell is small in size and I feel if u removed the secondary non monitored cell it would probably be equivalent to a high flow cat? ... this is just theory..if anyone has tried this, please let me know.
Thanks Tim

nomodsjk · 09-30-2014, 08:02 PM

Wow that's a good question. It sounds right but I have no clue. Definitely interested in responses

critical · 09-30-2014, 08:34 PM

the outlet diameter is still very small i believe. so not sure what you'd gain.

brancky3 · 09-30-2014, 08:53 PM

A lot of other car enthusiasts gut their cats. Probably won't be as big of a gain compared to test pipes, but definitely a power gain.

2012z · 10-01-2014, 07:27 PM

Quote:

Originally Posted by brancky3

A lot of other car enthusiasts gut their cats. Probably won't be as big of a gain compared to test pipes, but definitely a power gain.

Thanks for the response. I don't really want to gut the whole cat...just the second cell...a few collogues and myself was looking to do that on my car before installing the cat back system...but I got cold feet...not sure if it would sound bad, ect... I am sure someone has done this "mod" it looks fairly easy..again, didn't want any drone or rasp and such.
Thanks,
Tim

Super Werty · 10-01-2014, 07:45 PM

Heads---->stock exhaust manifolds--->AFR sensors--->cats---->rear 02 sensors---->muffler

so removing part of the cat will throw a code because the rear 02 will think the cat is damaged

Not sure how you are going to remove just part of the cat either without tearing the whole thing up...and for little to zero gain. Just get test pipes and a tune

2012z · 10-01-2014, 07:52 PM

Quote:

Originally Posted by Super Werty

Heads---->stock exhaust manifolds--->AFR sensors--->cats---->rear 02 sensors---->muffler

so removing part of the cat will throw a code because the rear 02 will think the cat is damaged

Not sure how you are going to remove just part of the cat either without tearing the whole thing up...and for little to zero gain. Just get test pipes and a tune

The stock cat has a separate 2nd cell AFTER the rear o2 sensor that is not monitored. That's what I am questioning to remove...if it was monitored it would have 3 sensors per back if that makes sense..

Super Werty · 10-01-2014, 11:50 PM

Quote:

Originally Posted by 2012z

The stock cat has a separate 2nd cell AFTER the rear o2 sensor that is not monitored. That's what I am questioning to remove...if it was monitored it would have 3 sensors per back if that makes sense..

I had to go back and look at some pictures. I see what you are talking about. And yes that "second cell" would not be monitored by the rear 02.

But IMHO there can't be much to gain here.

2012z · 10-02-2014, 08:29 PM

Quote:

Originally Posted by Super Werty

I had to go back and look at some pictures. I see what you are talking about. And yes that "second cell" would not be monitored by the rear 02.

But IMHO there can't be much to gain here.

Thank you for the response. Yeah I am not sure either how restricting it is....there is some...but 1-5 hp ? probably not worth the effort...lol.. thanks man.

Jordo! · 10-02-2014, 08:49 PM

It's a nice idea, but you'd probably be better off getting HFC's or TP's.

I guess if you can get to them easily enough, and can do the work yourself, no harm in experimenting, but those cats are a real pain to break loose -- search for "demon bolts"...

EDIT: Actually, come to think of it, are you sure that's not just a resonator you're referring to -- I've seen several sets of cats off the car, and I didn't think there was more cat after the O2 bung

2012z · 10-03-2014, 08:03 PM

Quote:

Originally Posted by Jordo!

It's a nice idea, but you'd probably be better off getting HFC's or TP's.

I guess if you can get to them easily enough, and can do the work yourself, no harm in experimenting, but those cats are a real pain to break loose -- search for "demon bolts"...

EDIT: Actually, come to think of it, are you sure that's not just a resonator you're referring to -- I've seen several sets of cats off the car, and I didn't think there was more cat after the O2 bung

It very well could be some sort of resonator, it didn't even think of that....its hard to tell cause it looks similar to a cat cell....but I agree with u...not worth the effort and probably is a resonator..
Thanks for all the feedback!

09-30-2014, 07:50 PM	#1 (permalink)
2012z Base Member Join Date: Nov 2011 Location: Smyrna TN Age: 48 Posts: 69 Drives: 2014 370Z 7A Rep Power: 14	Stock Cat Mod Ok, so I am going to ask the question... On the 370z the stock cats have two cells...one which is monitored buy the a/f sensor and rear 02 sensor..after that there is a cell I would refer to as a clean up cell... has anyone removed this? any gains noticed? obviously u would not get a MIL cause its not monitored.. just curious... the main stock cell is small in size and I feel if u removed the secondary non monitored cell it would probably be equivalent to a high flow cat? ... this is just theory..if anyone has tried this, please let me know. Thanks Tim __________________ Uprev tune, Garageline Catback, Mishimoto intake tubes, K&N Filters Last edited by 2012z; 10-01-2014 at 07:28 PM.

09-30-2014, 08:02 PM	#2 (permalink)
nomodsjk Premium Member Join Date: Apr 2014 Location: martinsburg wv Posts: 2,073 Drives: 2011 370z MB/7at Rep Power: 19962	Wow that's a good question. It sounds right but I have no clue. Definitely interested in responses 2012z likes this.

09-30-2014, 08:34 PM	#3 (permalink)
critical A True Z Fanatic Join Date: Oct 2012 Location: Washington Posts: 1,252 Drives: 09' 370z 7AT Rep Power: 16	the outlet diameter is still very small i believe. so not sure what you'd gain. 2012z likes this. __________________ Quaife w/ gears \|Stillen Gen 3\|SOLD FI Resonated Test Pipes \|SOLD FI 18'' \| 25row Stillen Race \| Progress 35mm/25mm sways \| Swifts/Koni\|Volk G25's\| Stoptech SS lines\|\|SPL Front/Rear Arms\|

09-30-2014, 08:53 PM	#4 (permalink)
brancky3 Track Member Join Date: Jun 2014 Location: Greer, SC Age: 37 Posts: 754 Drives: 14 370Z Gun Metallic Rep Power: 16	A lot of other car enthusiasts gut their cats. Probably won't be as big of a gain compared to test pipes, but definitely a power gain. __________________ 2014 Nissan 370z Gun Metallic 6-spd Test Pipes \| Nismo CBE \| Stillen Gen3 \| Swift springs \| Advanation Sway Bars \| RJM Clutch \| GTR DBA Premium Wheels

10-01-2014, 07:45 PM	#6 (permalink)
Super Werty Track Member Join Date: Jul 2013 Location: AZ Posts: 668 Drives: '13 Sport Rep Power: 13	Heads---->stock exhaust manifolds--->AFR sensors--->cats---->rear 02 sensors---->muffler so removing part of the cat will throw a code because the rear 02 will think the cat is damaged Not sure how you are going to remove just part of the cat either without tearing the whole thing up...and for little to zero gain. Just get test pipes and a tune Jordo! likes this. __________________ The Build

10-02-2014, 08:49 PM	#10 (permalink)
Jordo! A True Z Fanatic Join Date: May 2010 Location: nirvana Posts: 6,394 Drives: 2023 NATM Rep Power: 418	It's a nice idea, but you'd probably be better off getting HFC's or TP's. I guess if you can get to them easily enough, and can do the work yourself, no harm in experimenting, but those cats are a real pain to break loose -- search for "demon bolts"... EDIT: Actually, come to think of it, are you sure that's not just a resonator you're referring to -- I've seen several sets of cats off the car, and I didn't think there was more cat after the O2 bung 2012z likes this. __________________ Enjoy it. Destroy it. Last edited by Jordo!; 10-02-2014 at 08:52 PM.

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