# High flow cat converter



## curtisj85 (Jan 7, 2005)

i have a 95 sentra 1.6 and on ebay i saw the OBX high flow cat converter. would like to know any info about getting one or another brand or if it is even worth getting one. I have hs headers and getting cold air intake and would like to know about this before i install my exhaust. not worried bout it being smog legal im in louisiana they dont care


----------



## wes (Apr 30, 2002)

curtisj85 said:


> i have a 95 sentra 1.6 and on ebay i saw the OBX high flow cat converter. would like to know any info about getting one or another brand or if it is even worth getting one. I have hs headers and getting cold air intake and would like to know about this before i install my exhaust. not worried bout it being smog legal im in louisiana they dont care


Is your car a Cali. emissions car? If not do you have a stock cat under the car?


----------



## curtisj85 (Jan 7, 2005)

*cat converter*

not a cali and yes there is the stock one under the car and i wanna do 2.5" exhaust. im really trying to understand the exhaust what is good, needed, etc


----------



## wes (Apr 30, 2002)

curtisj85 said:


> not a cali and yes there is the stock one under the car and i wanna do 2.5" exhaust. im really trying to understand the exhaust what is good, needed, etc


Your stock cat is fine, leave it there. The OEM cat is 2.5" in and out. My car was dynoed through the stock cat if it means anything.


----------



## Nostrodomas (Jun 15, 2002)

curtisj85 said:


> not a cali and yes there is the stock one under the car and i wanna do 2.5" exhaust. im really trying to understand the exhaust what is good, needed, etc


I would advise you not to get a 2.5" exhaust. 2" has been proven to be the best size for an N/A GA16de 1.6l. Anything bigger with out forced induction will cause your car to loose power.


----------



## Ninety-Nine SE-L (May 5, 2002)

3 things:

1. Don't get a 2.5" exhaust for your 1.6 unless you got a turbo, YOU WILL LOSE HORSEPOWER. The only gains will be around 5,500-7,900 rpm and what do you know, the 1.6 cuts out at 6900. 2.0", bro, everyone here will tell you that.

2. The cat on the 1.6L and 2.0L flows just fine, you will not benefit by spending money on a high-flow cat.

3. I could be wrong, but I don't believe you have a cat under your car. I think what you have is a resonator. With the exception of Cali models, the 1.6L sentra lacks an under car cat, instead, the cat is built into the stock header. Here's an easy way to tell if it's a cat or a resonator. Look under the car where the cat would be. If the O2 sensor is before the 'tank', its a resonator, if the O2 sensor is built into the tank or after the tank, it's a cat.


----------



## curtisj85 (Jan 7, 2005)

*cat converter*



Ninety-Nine SE-L said:


> 3 things:
> 
> 1. Don't get a 2.5" exhaust for your 1.6 unless you got a turbo, YOU WILL LOSE HORSEPOWER. The only gains will be around 5,500-7,900 rpm and what do you know, the 1.6 cuts out at 6900. 2.0", bro, everyone here will tell you that.
> 
> ...


i didnt have a cat out of the headers like a lot that i saw mine is under the car but i need to check where the O2 sensor is.
Right now my headers are at 2 1/4" and they ae hooked to stock exhaust what size is stock


----------



## curtisj85 (Jan 7, 2005)

*rest of exhaust*

if the exhaust pipe is 2" what kind of muffler or tip i like the apexi dual N1 but i think it is 2.5" inlet is 2 1/4" good or bad


----------



## Nostrodomas (Jun 15, 2002)

curtisj85 said:


> if the exhaust pipe is 2" what kind of muffler or tip i like the apexi dual N1 but i think it is 2.5" inlet is 2 1/4" good or bad


The muffler should be ok, your muffler shop should be able to make it work.


----------



## wes (Apr 30, 2002)

Ninety-Nine SE-L said:


> 3 things:
> 
> 1. Don't get a 2.5" exhaust for your 1.6 unless you got a turbo, YOU WILL LOSE HORSEPOWER. The only gains will be around 5,500-7,900 rpm and what do you know, the 1.6 cuts out at 6900. 2.0", bro, everyone here will tell you that.
> 
> ...


1 and 2 are good advice. 

3 However is not entirely correct. The 95 and 96 federal emissions cars ONLY had a cat under the car, they did not have the close coupled cat.


----------



## Mod_That_Sentra (Oct 23, 2004)

OK, I have a question. what if I got a newer stock cat for my fed emissions car. I heard that after so many miles, the cats tend to slow down the exhaust flow. By getting a newer stock cat, would that increase any performance. Or what about an SE-R cat on a 1.6L sentra, any performance increase there?

thanks, Aaron


----------



## wes (Apr 30, 2002)

Mod_That_Sentra said:


> OK, I have a question. what if I got a newer stock cat for my fed emissions car. I heard that after so many miles, the cats tend to slow down the exhaust flow. By getting a newer stock cat, would that increase any performance. Or what about an SE-R cat on a 1.6L sentra, any performance increase there?
> 
> thanks, Aaron


Their either good or they go bad they don't slow down. On the B14's the 1.6 and SR20 had the same cat.


----------



## Nostrodomas (Jun 15, 2002)

You will not see any gains out of getting a new cat, unless yours is currently faulty or clogged.
Ser cat will also give you no gains.


----------



## meangreen200sx (Dec 28, 2004)

what the crap is up with the OBX cats anyway? the flanges on them are not curved they are straight. and they are supposed to be a bolt on mod. it aint happenin, bro. The nissan dealership told me i needed a new cat and was gonna charge me like 800 bux. So i just went and bought an OBX one. took it to the exhaust shop to have it put on and they are like the people who made this are idiots, # 1 your cat is built in to your header, #2 the flanges on the stock cat curve and bolt on at the bottom of the car. Its basically more like a resonator instead of a cat, so that is what they did, they just cut the flanges off and cut the stock resonator off and swapped them.


----------



## Nostrodomas (Jun 15, 2002)

You have a federal model b14. Only one cat in the exhaust manifold, and resonator.
Unlike the cali model, witch has the exhaust manifold cat, and also an under car cat. 
Looks like you got them mixed up. If your getting a error code because of the cat, you are going to have to replace the exhaust maifold cat. I have one to sell if you ned one. Since my car is now totaled.


----------



## wes (Apr 30, 2002)

Nostrodomas said:


> You have a federal model b14. Only one cat in the exhaust manifold, and resonator.
> Unlike the cali model, witch has the exhaust manifold cat, and also an under car cat.
> Looks like you got them mixed up. If your getting a error code because of the cat, you are going to have to replace the exhaust maifold cat. I have one to sell if you ned one. Since my car is now totaled.


Actually that is not entierly correct. The 95-96 federal cars ONLY had cats. under the car and no close coupled cat.


----------



## Nostrodomas (Jun 15, 2002)

Thanks for the correction Wes. I wouldnt want to spread the wrong info.


----------



## kstrongsyj (Feb 7, 2005)

I have a question concerning the CA model....I have a 97 cali 200sx....would that have both a cat at the header and an OBDII cat? If so....when I get a header and exhaust system, what do I need to do on the cat front to stay smog legal? Can I replace the whole system and just put in a smog legal cat and lose the header cat?


----------



## wes (Apr 30, 2002)

kstrongsyj said:


> I have a question concerning the CA model....I have a 97 cali 200sx....would that have both a cat at the header and an OBDII cat? If so....when I get a header and exhaust system, what do I need to do on the cat front to stay smog legal? Can I replace the whole system and just put in a smog legal cat and lose the header cat?


This is documented in NPM as they did this on project 1.6, they have pictures in everything.


----------



## Nostrodomas (Jun 15, 2002)

kstrongsyj said:


> I have a question concerning the CA model....I have a 97 cali 200sx....would that have both a cat at the header and an OBDII cat? If so....when I get a header and exhaust system, what do I need to do on the cat front to stay smog legal? Can I replace the whole system and just put in a smog legal cat and lose the header cat?


Since you are in Cali, if you install a header you will fail smog no matter where you put the o2. You will have to keep your stock exhaust manifold, ad put it on come smog time.
To make sure the o2 gets the right reading you will have to replace the o2 sensor behind your under car cat.


----------



## Ninety-Nine SE-L (May 5, 2002)

there are 3 models (apparently...and I could be wrong on a few)

Cat in mani, no undercar cat:
96-99 Sentra 1.6 (Fed)

Cat in mani, cat under car (2 cats):
95-98 200sx 1.6 (Cali & Fed)
95-99 Sentra 1.6 (Cali)
95 Sentra 1.6 OBD1 (Fed)

No mani. cat, cat under car:
95-97 200sx 2.0 (Cali & Fed)
98 200sx 2.0 (Extra long cat) (Cali & Fed)
98-99 Sentra 2.0 (Extra long cat) (Cali & Fed)


----------



## kstrongsyj (Feb 7, 2005)

Nostrodomas said:


> Since you are in Cali, if you install a header you will fail smog no matter where you put the o2. You will have to keep your stock exhaust manifold, ad put it on come smog time.
> To make sure the o2 gets the right reading you will have to replace the o2 sensor behind your under car cat.


Is that for the visual inspection or the emissions will fail? I am not worried about a visual inspection


----------



## Ninety-Nine SE-L (May 5, 2002)

IMO, get a piece of sheet metal and put it over the header. Cut it into shape so it looks like the stock manifold.


----------



## Ninety-Nine SE-L (May 5, 2002)

oh while I'm replying. It seems my catalyc converter is starting to go. When I gun it on the highway, the whole car fills up with that sulfer smell. I called up Greg on the road and he said a new cat is $306 (which is expensive to me). 

I think instead, I'm jus gonna ditch the cat since I don't have emissions. I'll extend the pipe, put on an O2 sensor fooler, and maybe use the extra room to add in a resonator. Anyone make a good 2.5" resonator?


----------



## Nostrodomas (Jun 15, 2002)

Ninety-Nine SE-L said:


> IMO, get a piece of sheet metal and put it over the header. Cut it into shape so it looks like the stock manifold.


Any smog tech will be able to see right through that lil disguise.


----------



## Ninety-Nine SE-L (May 5, 2002)

oh yea, "tech". Kinda like the techs a autozone who tell you that you can use motor ol in the gearbox rather than gear oil.


----------



## Nostrodomas (Jun 15, 2002)

Common man, be serious. I dont know about your area but our smog techs take there jobs very seriously, since there are great fines to pay for passing a car with failing parameters.


----------



## kstrongsyj (Feb 7, 2005)

That's why you need a VERY close buddy that is a smog tech in your county


----------



## Nostrodomas (Jun 15, 2002)

If your not worried about the visual, then its ok. It should pass smog.


----------



## kstrongsyj (Feb 7, 2005)

Nostrodomas said:


> If your not worried about the visual, then its ok. It should pass smog.



Cool. If it will sniff test clean, that's pretty much all I need


----------



## mudpaws (Feb 25, 2009)

ahh I wish we had no emissions here..


----------

