• The site migration is complete! Hopefully everything transferred properly from the multiple decades old software we were using before. If you notice any issues please let me know, thanks! Also, I'm still working on things like chatbox, etc so hopefully those will be working in the next week or two.

Need advice on a getting a new cat

0

01GT guy

New member
So I'm new to this forum and I believe I am posting this in the right section. I have a 2001 Grand Prix GT and I believe its a 3.8L v6.

I have been having some issues with my car stuttering while idling and my service engine light flashing. I have had a broken cat for years and it seems to be starting to give me trouble. So I am thinking about getting a new 2" down pipe with cat back from zzp. So here are my questions...

1. Is zzp reliable?
2. What are all the parts i would need to mount the 2" down pipe to the stock manifold and exhaust?
3. Is there any maintenance I have to keep up on if I install the new down pipe?
4. How will it affect my gas mileage?
5. Will it have any adverse affects on my car in a few years?

Thank you in advance!
 


camopaint0707 said:
But seroiusly, go with ZZP. They are good. I would email them for better advice.
Click to expand...

If you take ^^ this guys advice, make sure you get a pcm with the cat codes removed. Most of the time ZZP's "good" stuff sets the code because it doesn't meet the pcm's requirements. It's likely easier/cheaper to find someone that did headers and buy their downpipe.
 
^^^ x2 or get a magnaflow universal cat. I paid $70 for mine I believe and never triggered a code in my 99GT
 
Howdy 01GT guy:

My wife has a 97 GT, I put a 2.5 inch ZZP 304 stainless pipe with cat on it because I kept getting a P0420 code. The pipe fit with no mods and wife says it made it sound better. Milage has gone up about 1 or 2 MPG.

I was still getting the P0420 code so I did the anti-fouler trick. I had to change the O2 sensor out and used a Bosch replacement because the stock one was to large to fit the anti-fouler. Since then no more P0420 code. The truth of the matter is that the old O2 sensor may have been bad, but everything together works so I am not changing a thing.

With the U-Bend deleat that is part of the new pipe I had to clearance the underside to fit the O2 sensor with the anti-foulers. I just used a bottle jack to dent around the sensor to make it fit.

As far as the ZZP downpipe goes you will not find a better built one IMHO.

Good luck
Robert
 


slick2500 said:
If you dont have emissions just put in a piece of strait pipe, and do the non-fouler trick.
Click to expand...

I actually totally forgot that I don't even have to do emissions. So should I get or new downpipe or by strait pipe do you just mean I should find a piece of 2"(i believe) pipe and weld it to where I delete the cat. And how exactly does the non-fouler trick work? Also if I should get a new downpipe, is there something that will fit a 2.5" to my 2"(i believe) stock maniifold?
 
01+ cars are more sensative to cat converters than 97-00 cars because of the new cat diag inside the PCM.

I would buy a cat converter with a warranty and weld it in yourself if you can. I just did this on my sisters car.

Or price out a whole downpipe unit that "doesnt" run a high flow cat and install it. A highflow unit is what sets the ses off again.

And the non fouler trick just puts the o2 sensor further away from the exhaust gases, it makes it not stick down as far inside the pipe.
 
You must log in or register to reply here.
Back
Top