Header and manifold Thread

[Whitehispanic]

I like this info because i really im learning about this also. This is very interesting info

[nawarkk]

Ok a couple more questions:

Will the stock catalytic converter bolt up to the headers? Will it be removed or will I have to buy an adapter? Should I even worry about the Catalytic converter? Do I need to purchase a high flow Catalytic converter?


The headers exit at 3 in pipe by the Resonator which is a smaller diameter (2.25 in?). Would it be better to run 3 in pipping all the way back and get rid of the stock pipping that comes from the factory or should I just buy an adapter also? Is there a significant power loss from the 3in piping all the way back to the stock pipping?


Just making sure I have all my facts straight

[TheOtherNick]

1. You do dont reuse any of the stock dp where the cat is located.
2. Do you have emission checks? If not go with out a cat. If you do get a 3" inlet cat and it will bolt in the dp of the headers.
3. Unless you are planning to run over 350whp the stock cat back will be fine. The headers bolt to it with no problems.

[Abrasive]

Ok a couple more questions:

Will the stock catalytic converter bolt up to the headers? Will it be removed or will I have to buy an adapter? Should I even worry about the Catalytic converter? Do I need to purchase a high flow Catalytic converter?


The headers exit at 3 in pipe by the Resonator which is a smaller diameter (2.25 in?). Would it be better to run 3 in pipping all the way back and get rid of the stock pipping that comes from the factory or should I just buy an adapter also? Is there a significant power loss from the 3in piping all the way back to the stock pipping?


Just making sure I have all my facts straight

Just noticed the years of cars in your sig.

This is just my opinion, based on my own personal experience with my 2002. On an '01 up, I would definitely run a cat. I didn't for a few years and no problems, but then suddenly developed the symptoms you will find in the following link. Poor mileage, surging idle, etc.. I installed a cat, turned the rear o2 back on and all the issues vanished.

http://www.grandprixforums.net/f65/r...ewer-7092.html

[TheOtherNick]

I run no cat and have not had a problem. I was throwing a insufficient switching code when I first did a dp with no cat, put in an 02 emulator and that fixed it.

[nawarkk]

hmmm so not having a cat will lower my gas mileage and create other problems huh?...

Could I use the stock catalytic converter? Or will problems occur?

How much is a high flow catalytic converter? I heard they are in the $200+!

[TheOtherNick]

No you would not reuse your stock cat. You would need an aftermarket high flow one. Go shop around for one.

[matt5112]

they're $100 at most.

That link about throwing off your fuel trims only applies to 01+

[alkygto]

Just bought the SSAC headers they should be here tomarrow should I

A. hook it up to my SLP catback and delete the cat (then what do I need?)
B. Gut my factory cat (which I believe is clogged but no codes) and put it in the system.
C. Spend more $$$$ and buy an aftermarket cat (whose is best?)

Car is a DD with 145,000 mostly trouble free Mobil 1 (every 4000) miles.

[matt5112]

What year is it? 01+ run a cat.

Otherwise its up to you.

Apparently running without will cause your bumper to be discoloured near the tailpipes along with a different sort of smell you're probably used to.

[nawarkk]

So something like this should do the job?

3" Stainless Steel Catalytic Converter HIGH FLOW CAT : eBay Motors (item 280452848347 end time Feb-16-10 09:59:25 PST)

[matt5112]

yup

[nawarkk]

Ok one more question and I think I pretty much understand what I have to buy. The "O2" sensor will plug into the headers or into the cat? Because I didn't see any place to put the sensor into the cat I linked. Also would I just get an adapter that would fit from the high flow cat to the rest of the catback?


This is all starting to make sense

[matt5112]

There should be a bung for the rear O2 sensor in the section of pipe that goes after the cat.

That pipe bolts to the resonator/the rest of the catback.

[nawarkk]

Ok since that link doesn't specify if it comes with a place to plug the O2 sensor into it, how big of a diameter circle would need to be drilled so that I can put it in there?

[matt5112]

No... the headers should come with a piece of pipe with a flange on it to mount to your resonator that already HAS the bung you need for your o2 sensor.

[alkygto]

What year is it? 01+ run a cat.

Otherwise its up to you.

Apparently running without will cause your bumper to be discoloured near the tailpipes along with a different sort of smell you're probably used to.

Car is a '97 ( see New Improved Sig! ) and I guess I'm going cat delete and see how that goes. Any idea of the gains i will see with my combo? excited to get these on as I have'nt really driven the car for 6 months so it's new to me again, I forgot how much fun it is to drive.

[matt5112]

Headers will be a big gain since it'll get rid of that knock you probably have at the moment.

It'll basically go from a 3.8-3.6 level to a proper 3.4 setup level.

Get a proper tune or a tuned PCM next. Really wakes up the car.

[Abrasive]

I run no cat and have not had a problem. I was throwing a insufficient switching code when I first did a dp with no cat, put in an 02 emulator and that fixed it.

Well, like I said, mine was fine for a few years and then one day it just started happening. Some never have the issue, some get it right away and some like me are fine for a while and then it starts. I would have never figured it out had it not been for that thread. And just an FYI, IF you ever do get issue with the cat diagnostic test, an emulator won't stop it. The cat diagnostic purposely creates conditions to check for fluctuations in the reading from the o2 sensor and the signal from an emulator will remain constant which is not what the PCM will want to see.

[TheOtherNick]

Yeah I just went on a whim and it worked. I have no problem putting a cat on it if I have to.