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View Full Version : Catylitic Convertors... My car has 4... I want them GONE. Can it be done?



WOT
06-07-2009, 10:33 PM
I really didnt know where to post this, but I figured there are alot of people that could help me here.

Anywho, I drive a 01 Infiniti Qx4. VQ35De engine, 2wd. It has 4 cats, and 4 02 sensors.

I built an exhaust 2-3 years ago, and it need to be redone as its rusting pretty bad. What I would like to do is completely remove everything after the factory headers. As Im sure the cats are a HUGE restriction. What I dont understand though, is how it will cause the car to run. As it goes:

Header -> 02 -> cat -> 02 -> cat (X2 as this is on each side)

From my understanding, the rear 02's dont do anything, but I would have still have to weld bungs for them. But I dont get if I simply put both 02 sensors after the header, would the car still run right? Would it adjust properly?

Im hoping there are some people here with some experience that could help me it. Ive never done a full exhaust like this, and I dont know if my fluxcore welder is upto the task lol, I dont want it cracking and failing in a short ammount of time. Is there a cheap place to find the cat flanges / 02 bungs?

Thanks for any help appreciate it

Skip01
06-07-2009, 10:38 PM
Might throw CELs and run rich

I wouldnt myself...would be a lot louder

WOT
06-07-2009, 10:43 PM
I dont care about the noise, I was actually disappointed when I removed my 2 factory mufflers, and replaced them with a single magnaflow 40 series, 2.5" piping, and a side exit, and its still pretty **** quiet

I know the cats would probly free up some ponies, air flow and some growl
Just curious how it would affect the cars running

Ellsworthz
06-08-2009, 12:52 PM
do it, might sound a little cam'd

BASS_WARRIOR
06-08-2009, 12:55 PM
Do you guys not have emissions tests up there?

JBGabriel
06-08-2009, 12:56 PM
If you do go this route im sure you know it is very illegal. But here is a way around the CELs. They make o2 simulators that you can buy and plug the sensors into and they trick the engine into running properly.

Varinabassing
06-08-2009, 12:57 PM
I know when i got rid of the cats i had to do a flash and adjust the computer so it didnt run rich and depending on where you live can be a son of a ***** to get to pass inspection lol But it will sound awesome and yes you will feel some ponies wake up when you get in her lol Good luck i not much of a welder myself but my bud is

GiganticPrune
06-08-2009, 01:04 PM
on subarus i know you can usually get rid of the CEL that is thrown by not having cats with these little $30 adapters premade.

all they are is spark plug anti foulers that can be found at any auto parts store, i bought some and drilled em out a little so the o2 sensor could fit.

it spaces the o2 sensor farther out from the exhaust stream so it doesnt read as hot since theres no cats now, then it wont throw a code.

i dunno about emissions for you. in IL, as long as you dont throw a code youre cool. no visual check.

GAM3OVR
06-08-2009, 01:15 PM
most O2 sensors can be bypassed by having a 1.3k - 4.2k ohm resistor.

Or you can be relly cool, and replace al your piping. remove the piping and get an open-ecu tune for around $350.

You will add about 6% -12% Hp on a petrol engine.

Plus they can disable any sencors in the open ECU tune that you don't need. The computer will act like they don't even exist, so they will never come on, or screw you over in a emmision test.

scottyfkachris
06-12-2009, 01:20 PM
The 2 cats after the last o2 sensor can be removed and the engine will be fine. If you remove the one inbetween the cats then you will have to fool the one behind them. The 2 o2 sensors work simultaniously basicaly the first one gives it a standard and the second one uses it to tell whether its lean or rich. Atleast from my understanding thats how it work

mm0142
06-12-2009, 01:29 PM
recycle them bad boys though you can get about $70 each here in tx im sure its a lil more in canada .

frkkevin
06-12-2009, 03:33 PM
you said you changed your mufflers.. but was there no resonator?! most cars with have a few cats.. then a resonator... then mufflers

ThatChevyGuy
06-12-2009, 03:37 PM
How does it sound? I have pipes on my 4.0 v6 and it sounds deep, but anything smaller than that would sound too raspy.

ThatChevyGuy
06-12-2009, 03:38 PM
The 2 cats after the last o2 sensor can be removed and the engine will be fine. If you remove the one inbetween the cats then you will have to fool the one behind them. The 2 o2 sensors work simultaniously basicaly the first one gives it a standard and the second one uses it to tell whether its lean or rich. Atleast from my understanding thats how it work

Look up a dummy sensor, mine had 4 cats as well, and a resonator near the tail pipe. Thats what i had to do

gnatnoop
07-18-2009, 07:04 AM
it will NOT pass any kind of smog/ emissions test