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cat is clogged, is it worth the money to buy a emulator and a downpipe?

A

alivepills

New member
im preatty sure my cat hasta be dealt with and im not sure if i want to spend that much money to just buy another one if i wanna do a little bit of modding anyways. so howhard is it to put a downpipe in and eliminate the cat and 02 sensor? and does this affect how the engine runs and is there anything i need to worry about when messing around with this?
 


Buy a ZZP catted DP if you're worried about it.

3" bolt in.

Stainless or mild is your choice.

The year if the car decides whether or not you can run an O2 sim. 01+ cars dont like you running without a rear O2. You can run without the cat as long as the codes are set to non-report but you must run the rear O2.
 
i have a 2000 but its the l36, is there a difference?and how do i set the codes to non report? and if my rear 02 is blown like i believe it is do i need to replace it for the car to run properly?
 
Not really.

You can run the O2 simluator.

So what I'd do is run a 3" ZZP catless DP and an O2 simulator.

Unless you need to pass a tailpipe test for emissions.
 
I just went through this same stuff. If your looking at cost of a oem style replacement convertor it was cheaper to buy a 3 inch catless down pipe and a zzp stage one computer with the codes deleted. I saved about 50-75 going that route. Id stay away from the autozone replacement cat. I tried that and 2 years later cat was bad again.
 
how complicated is this job to do myself? i am mechanical but not very expirienced at all. i would need to buy a new computer? how much are these? and how hard is it to swap it out?
 


Mine wasn't to bad, did in my driveway. You don't need the computer but for what it costs for o2 emulator compared to the computer which does more I went with computer. Also even with the computer and all gaskets along with downpipe it was still cheaper then going the route of replacing the cat
 
To get a new PCM, the choice is up to you...I'm sure there are some 3800 tuners in Minnesota...I'd check a local GP forum or something and if someone has DHP, they might just hook it up and turn the code off for free...depending on how nice they are up north lol.

As for the downpipe...my exhaust guy would put on downpipes...for like $50. I'd rather scrape some knuckles and cuss a bit to save myself $50 for something that can be done with some PB blaster, a couple hours and a pair of jackstands if the bolts are frozen on there. I would...get a catted ZZP Downpipe...3". Keep this in mind though, the SES light still might come on since some aftermarket converters flow well enough that the PCM thinks a cat still isn't there. Also, something else to think about...Speed Daddy slip fit headers are about the price of a catted 3" downpipe nowadays...and you can just slide a 3" in/out converter in the downpipe section or put in the straight pipe piece they give you. They are about $200 and will net you 3 times the gains as a DP would.
 
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ok i think i am gunna try and do the downpipe myself, and get an 02 emulator for 50 bucks. i am looking at the zzp 1.0 pcm , how much improvement performance wise should i expect and are there many negatives to running an aftermarket pcm?
 


DHP PCM here.

Get one from 3800performance. As for a stock car with a PCM...its still worth it...like Nick said...don't forget the skip shifts too.
 
I have read a lot of the threads about these two items. However, it is hard to to put all the info together because i get confused by the acronyms (DHP, PCM) and terminology. I have a buddy who says he can just gut the cat converter since a clogged cat is a common issue. Without going into detail on he does it, if he was to do that, would i even need to have 02 sensors? For legal reasons, i do not want to do this cause i'm not sure if Indiana has emission laws, but i really need to get this fixed asap. If this is not a good idea, then whats the best solution in dealing with clogged cats and O2 sensors. I would like to avoid buy a new cat converter since SlowRR said his went bad. Also I have no interest in adding any mods, i just want my grand prix run right. I am desperate for anyones help and i would greatly appreciate it. Thanks.
 


If that's all your looking to do gut the cat. And get a o2 emulator. You'll still need the emulator to. Make pcm think the cat is not only there but doing its job. As far as legallity if anyone looks under they will still see the cat and the emulator will elimate the ses light so you'll be fine with that.
 
ok so after researching the indiana admission laws, i have found out that indiana only tests for emissions in Floyd, Lake, Clark, and Porter counties. So, if i do not have to worry about getting tested and i do not care about my SES light coming one then i would not have to buy an O2 emulator?
 
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