I have a 2002 3.5 6 speed. All maintenance has been done new clutch, valve covers, crank cam knock sensors, radiator, illuminas/eibach, tierod ends, half shafts, crank shaft seal, high pressure ps hose.

Mods already done: VIAS block plate, struts, springs, Berk intake.

I need advice from a great group of Maxima enthusiasts. I do have a code for inefficient Bank 2 precat. I have all 4 brand new oem oxygen sensors either ready to install or sell. Now to the point. I have about $400 to spend on the car now and possibly more if you guys think that replacing all of my o2 sensors is a waste. Probably could sell them for ~$100 each. I definitely want to get an oil catch can because I burn 2 quarts every 3,000. My thoughts are to get the NWP intake spacers or catback (most likely Megan) or the last y-pipe from cattman. What mods do you all recommend based on personal experience?

I wouldn't mind getting rid of the CEL (gas mileage is very low 20's at most and I do not have a lead foot) so maybe only replacing bank 2 heated o2 sensor? Thanks guys.

Headers.

I'll buy one of your primary sensors.



My favorite mods:
Headers
LRMAF
3" Exhaust
MMI's & ETL




In that order, since the MMI/ETL combo brought everything together nicely.

If you don't do a lot of redlining, drag racing and you don't mind tearing apart the whole intake then I would suggest the spacers. Great mod for everyday driving and greatly improves the torque band which is nice for the daily drive.

My recommendation would be in line with Nmex, especially given what you report to be your current code issues. Cattman Headers just went into possibly their final/last batch, but I suggest you call him, he may have arranged for some extras to be made. You'll have to put a small (about $250) deposit down and then pay the rest when they are completed, sometime in October.

Headers, not a y-pipe....will replace your pre-cats. Sell the two secondary O2's you've got, you'll not need them with the headers and y-pipe...so there is $200 more in your pocket. If your front O2's are fine, sell those or return them, there's another $200 and you've paid for the everything but shipping on the headers/y-pipe.

EDIT: Shameless Plug - I have a couple of oil catch cans for sale if interested. These actually work!

As mentioned above, go with headers, or maybe gutting your precats if you wanna save. Then get some spark plug non foulers for about 5 bucks from advance auto.

If you go headers, OBX needs a little modification to fit right but are more affordable.
Gutting your cats is free short of labor (most of which have to be spent on installing headers anyway).
Headers/gutted cats will give you more power gains than spacers or a catback I believe (could be wrong).

Most people with the p0420 and p0430 tend to have bad cats which can cause bad fuel economy.

You'll be seeing several good things with doing either headers or gutted cats:
More power,
No more CEL from inefficient precats,
Possibly improved fuel economy if your cats are clogged.

There'll be a difference in sound, but whether that's a good thing or not is up to the owner of the car.

I bet you're losing oil because of a failed rear VC, or at least contributed to by. So here's my advice:

Step 1. Spacers
Step 2. 6th Gen valve covers
Step 3. new plugs
Step 4. gut the pre-cats *OR* get headers

He's done VC's already.

I hate you

Fine, then.

Step 1. Spacers
Step 2. gut the pre-cats *OR* get headers

The real value in getting an aftermarket Y-pipe is that you keep the pre-cats and don't have to fake the O2 sensors. The gains aren't there on the 3.5... certainly not compared to headers.

You ALWAYS catch me... Had to take the opportunity. Looks as if this gutted pre-cat movement might take off.

I'd like to see a Dynojet of it.

Wait til you see my gutted pre catts with 3'' warpspeed y-pipe

Now why would we put a 6th gen VC on are cars i think i missed this...

cos it's cheaper and more readily available. old news

What do u use to gut the precats?

The 6th gen VC's were redesigned to resolve the leakage that typically occurs at the #3 coil after they get old. They bolt right up to our 5.5 gens, and they cost about 1/3 the price of the 5.5 VC's... something like $50 vs. $150.

Like Steve said: old news. But there's the answer anyway, in case someone new to the issue stumbles into this thread.

A good mechanic and $250.

Or an air chisel, a breaker bar, a lift, a first aid kit and more patience than God.

Search "precat" or "pre-cat" or whatever else comes to mind on the topic when research is warranted.

Thanks for the replies so far. Definitely did both vc's 6th gen) and spark plugs. I am interested in gutting the precats but I am also scared of not doing it 100% right and causing a small chunk of cat innards to be sucked back into my engine and you know what would happen then. Tell me this, if I gut the precats and get the y pipe, do you think the gains are pretty much the same as headers? I am interested because

1. less work
2. half of the cost

Also, I know o2 sims are hard to come by these days so can I add a bung to my exhaust after the main cat for the sensor and will that suffice in getting rid of the cel? Thanks.

You said "cat innards!!" Lmfao!!

Like I said before, go get some $5 spark plug non foulers to take care of the CEL. Do a search on google about them or on here since it's been talked about recently.

If you're trying to get gutted cats+ ypipe for a 'header' set up, why not just pick up a set of obx headers then. I don't think you're gonna save too much after buying a y-pipe.

For some reason, I was under the impression that obx stopped making 3.5 headers. I thought that the only headers left for now are the cattman ones which are around $850. From what I father the spark foulers help if you are keeping the precats at least intact.

OBX is available, however Cattman is selling his business or shutting down, so no more Cattman for you. Foulers can be used to spoof the secondary signals when you don't have pre-cats (because of headers) or if they're gutted.

Basically, flip both of those things upside-down.

Wont be Dnyojetted so, can't compare.

my CEL came on and came off once for 1 day... havent seen it off since lol... anyways my opinion on mods...
SSIM
cattman 3"
NWP spacers
Headers ( OBX or Cattman)

Header
Spacer
Catback
Tune

OK NOOB question.....what is MMI and ETL???? I at least know what LRMAF is.....I used to think it was short for LARGE MAF...lol.

Where'd you find that? The spark foulers are being used by someone who gutted the cats right now.

Motor Mount Inserts (Energy Suspension)
Engine Torque Link (NWP Engineering)

Both of these mods keep the engine braced down more securely to the frame. This means energy isn't wasted lifting that heavy engine as it torques to one side under load; (or in the case of our transverse engine, that would be forward.) The result is a more efficient application of torque to the drive wheels. Another benefit, by rocking/lifting the engine less, you address the primary cause of wheel hop. Yet another benefit, the transmission shifts gears more smoothly because it's not moving around as much. Basically, it's all good.

The downside is noticeably increased NVH. Now go look up "NVH"

To add to that, I realized I hadn't added any power mods in the past year, but those 2 mods together helped me feel more powerful, added response, and lose traction everywhere and anywhere.

Also, LRMAF = Land Rover MAF housing.

Quicker response... good one, Manny. To sum up:

• Reclaiming lost power to the wheels
• No more wheel-hop
• Smoother shifting
• Quicker response (less lag)
• Better hook-ups
• More aggressive feel to the car

This is why solid poly torque-mount bushings is my all around favorite mod. This one simple thing brought about so many beneficial changes to the car. It's truly transformational.

Sounds like you're describing your sprint booster

I no haz teh Booster anymore.

Broke the retainer clip removing it early last Winter, and there's no way to reattach it securely, and no way I could see to hack it with zip-ties or what-not. I decided it was safer to do without, than to drive in fear of having my throttle pedal go dead at a moments notice.

are 6th gen valve covers sig mod list worthy?

Around here, anything is.

Look at it this way, how many sigs have you seen listing "cleared side markers"? Seriously.

It's your sig, do whatever you want. Typically, mod lists are for performance. But some people differentiate between performance and visuals. If you like, you could be the very first guy to put a list of "Maintenance Mods" in his sig. Brand of motor oil, nitrogen in your tires, turtle wax...

hahahah yeah, i didnt think of it being to worthy, but it is one of those things only 5thgen org members would really understand why any 5th gen would have 6th gen valve covers.,
i actually almost forgot I did them.

Uh oh. I just realized "smoked sides" is actually in your sig, Prophecy.

Well then. Um... yeah. There it is then.

Thank you all for the input. I have decided. I am going to get the OBX headers and the IM spacers. I figured that I may as well get the spacers now since I will have to take it apart to get clearance for the header install. My only other question is should I sell all of the o2 sensors or maybe just replace specific ones for the "just in case it was on its way out" reason.

i would def inspect any that you can get access to when doing the work, and if there is any slight sign of wear then it only makes sense to change em.

Yeah Roch, I do have em listed.. i tried keeping it discreet as possible ...

Of course I'm just teasing you. It's your sig, and there are no rules excepting peer pressure.

Perhaps I should add "titanium BOP bolts" to my sig? Do you think?

Nah-h-h.