# Headers, Catalytic Converter and Catback - Noob question



## jljordann922 (Jul 1, 2013)

I just bought a header and catback exhaust for my 1996 200sx and have some noob questions and want it to be street legal (NY)

As far as I understand by replacing the exhaust manifold with the new header I am taking the front catalytic converter and O2 sensor out. Is this true and does this make my car illegal for street use? Will a mechanic install the headers?

Once the headers are in...it would connect to the next catalytic converter...I have a stock cat. Would it be recommended to replace it with a magnaflow high flow cat? Then I would connect that end to the catback exhaust. 

Am I missing any pipes or other necessary parts? If the header is illegal, is there any other way around it?

How do I recalibrate the o2 sensors with the new air-flow and setup?

Thanks for any help


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## ahardb0dy (Nov 9, 2003)

You can not legally remove any Cat converter, neither can a mechanic unless it is defective and is being replaced.


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## rogoman (Dec 16, 2004)

Check out this thread:

http://www.nissanforums.com/b14-95-99-chassis/170271-bolt-header-question-200sx-se-1-a.html


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## jljordann922 (Jul 1, 2013)

Thanks that helped


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## wilburk (Dec 29, 2012)

Any time you're making modifications like this it seems logical to think about resale potential/changes. If you're ever planning to resell the car, how is this going to affect your making the sale.


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## jljordann922 (Jul 1, 2013)

I appreciate the opinion but come on..resale??? I bought this car for $800...it's 17 years old I'm lucky if I get a G for it..the value after its done is the least of my worries


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## wilburk (Dec 29, 2012)

Fair enough. Just mentioning that because I recently (4 months ago) sold my 1998 200sx se for $3500. One of the biggest apprehensions from the seller was about the after market cold air intake. 

Best of luck on your exhaust adventures.


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## azkicker0027 (May 31, 2002)

i had to relocate the pre-cat O2 sensor further down because the header location only monitors 2 out of the 4 cylinders. i had to lengthen the O2 sensor wiring to accomplish this. I also recommend to move the post cat after the new cat you'll install to avoid the SES warning to light up.


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## EvilPotato (Sep 6, 2005)

where did you move it to? i have a 4-2-1 (2nd gen) hotshot header and i've been thinking about moving the upstream o2 sensor for a while but where the collector becomes 1 pipe seems too far down and might not heat up the sensor enough to get a reading.


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## BeyondBiscuits2 (Jan 18, 2006)

In regards to legality, it depends on the state you are living in. Check with your Department of Motor Vehicles, they should have guidelines about catalytic converter removal. For instance, I'm certain it is HIGHLY ILLEGAL in California to remove a catalytic converter, but here in Tennessee, no one thinks twice. If it is legal in your state, you can take your car to an exhaust shop and get whatever pieces made you need, though I doubt they'll install them. I know plenty of shops around here, where it isn't illegal to remove catalytic converters, who will make "test pipes" but won't actually remove the converter for you.

P.S. if you have emissions testing, don't even think about removing your catalytic converter.


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## smj999smj (Jan 1, 2006)

It is against the Federal Clean Air Act to remove, defeat or bypass a catalytic converter for any reason with the exception that the vehicle is being exported overseas to a country where unleaded gas is not readily available. This includes vehicles that will be used for what we refer to as "off-road" use. All the info you need can be found here:

http://www.epa.gov/Compliance/resources/policies/civil/caa/mobile/exhsysrepair.pdf


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## EvilPotato (Sep 6, 2005)

yeah we have nazi stuff here in California, my car actually passed the emissions part of the test without the pre-cat, with the hotshot header on, with lots of headroom on both NOx and CO readings but the results were disregarded because it failed the VISUAL part of the inspection. Seriously, visual? so now my car is tagged a gross polluter and every registration time DMV sends an offer to tow my car for free if i donate it, being a VISUALLY gross polluter, along with my renewal form.


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## azkicker0027 (May 31, 2002)

EvilPotato said:


> where did you move it to? i have a 4-2-1 (2nd gen) hotshot header and i've been thinking about moving the upstream o2 sensor for a while but where the collector becomes 1 pipe seems too far down and might not heat up the sensor enough to get a reading.


heating shouldn't be a problem if the O2 sensor heater circuit is intact when you extend the wires. it just makes sense to monitor where all the pipes collect because my car ran really rich with just half the cylinders monitored. and in turn, improved my gas mileage.


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## stevehendo34 (Aug 17, 2011)

My 1999 se-r 200sx dose not throw codes running without the rear sensor.

I screwed up the sensor torching on exhaust flange bolts when changing the pipe. I retaped the whole and screwed in a spark plug because the threads are the same as the O2 center. 

My neighbor is Nissan mechanic, he says often people just weld the rear one closed on my car.

No code are being thrown buy ECU.


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