The Top DSM Community on the Web

For 1990-1999 Mitsubishi Eclipse, Eagle Talon, Plymouth Laser, and Galant VR-4 Owners. Log in to remove most ads.

Please Support ExtremePSI
Please Support Fuel Injector Clinic

Should I remove my catalytic converter?

This site may earn a commission from merchant
affiliate links, including eBay, Amazon, and others.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Munster000

15+ Year Contributor
52
0
Sep 18, 2005
bloomington, Minnesota
I've got a 91 TSI with about all the 1st stage upgrades....

I've still got a catalytic converter, should I take it off? There are no emisions testing in mn, so that's not a problem. Is it possible my car won't run as good? Lose power? I've heard storys of people running into problems after doing this.

Thanks
 
I've removed it on both of my DSM's I've owned and nothing bad happened. It'll smell different, I've had many people ask me what "that" smell is. Only downside is I know it's killing the environment.
 
Okay, I guess another part of my question is....what are the advantages?
 
Personally I would replace it with a hi-flow 3" cat, but that's because I actually care about the air I breathe.
 
Awsome....thanks for that thread. The first reply said:
"If you take it off and don't do a fake O2 Sensor Radio-Shack job, you will throw a cel."


What is he talking about and how do you "fake the o2 sensor?"

Thanks
 
Munster000 said:
Awsome....thanks for that thread. The first reply said:
"If you take it off and don't do a fake O2 Sensor Radio-Shack job, you will throw a cel."


What is he talking about and how do you "fake the o2 sensor?"

Thanks

I think he is talking about this. I have no experience with it but I found it on www.vfaq.com under the exhaust section. I am currently catless and I still have 2 o2 sensors, one being where the cat used to be. I did not install my exhaust/remove the cat so I'm not sure about how to reinstall the 2nd o2 sensor.
 
Munster000 said:
Awsome....thanks for that thread. The first reply said:
"If you take it off and don't do a fake O2 Sensor Radio-Shack job, you will throw a cel."


What is he talking about and how do you "fake the o2 sensor?"

Thanks
Most of your OBD II system is to monitor you emissions. You have an O2 sensor by your turbo that the ECU uses (while in closed loop) uses to make adjustment to you air/fuel ratio (you need this one) The second one is located behind your cat. This one is to ensure that your cat is working correctly. I have not removed my cat on my dsm, but on another vehicle, it threw the check engine light, caused the ECU to go into a "Limp" mode and caused the car to run poorly. That car was also Turbocharged and i didnt really see a difference in power. If you are going to remove it, i would definitley put a piece on it to make sure that the ECU still thinks that the cat is correctly.
 
The rear O2 sensor serves ONLY ONE purpose, to check operation of the cat. It will NOT affect the car in ANY other way other than to let you know that the cat isn't functioning properly or is not there... The rear o2 can not cause your car to enter limp mode. If you remove the cat, you will spool considerably lower and quicker, gain some power, and the car will be louder and more throaty, especially when the wastegate opens. You may have to retune the car, but it shouldn't be too far out of tune.
 
High flow cats are cheap. It's not worth a pony or two to help kill us all.

Also, 1G's don't have a rear O2 sensor, so he has nothing to worry about in that department. We only have the upper O2 which is not effected in any way by what you do or don't do to your cat.
 
eclipsegsx1736 said:
The rear O2 sensor serves ONLY ONE purpose, to check operation of the cat. It will NOT affect the car in ANY other way other than to let you know that the cat isn't functioning properly or is not there... The rear o2 can not cause your car to enter limp mode. If you remove the cat, you will spool considerably lower and quicker, gain some power, and the car will be louder and more throaty, especially when the wastegate opens. You may have to retune the car, but it shouldn't be too far out of tune.
Interesting, makes me wonder why the previous owner had the rear o2 sensor reinstalled on my car w/o a cat, maybe just to avoid the CEL. Thanks for the info.
 
Just do a testpipe set up and get a highflow cat, that way you have three options.
1. Stock cat = good emissions, good sound, bad performance
2. High flow cat = decent emissions, great sound, good performance
3. test pipe = kills the environment, loud(still good), awesome performance
 
TSIMonsteR said:
Just do a testpipe set up and get a highflow cat, that way you have three options.
1. Stock cat = good emissions, good sound, bad performance
2. High flow cat = decent emissions, great sound, good performance
3. test pipe = kills the environment, loud(still good), awesome performance


^I'm going to do that.

Any articles that show how to do it so they are all interchangable?

where can I buy piping, fittings, and clamps?

Thanks for all the info.
 
With a straight through pipe you should gain power & see quicker spool. The disadvantages would be louder exhaust, sometimes boost creep, polluting the environment, car smells. It all depends on your car as to what things you will actually experiance, some say their car smells so bad they couldn't stand it without a cat while others don't have any issues. I know of some that have switched from straight through pipe to high flow cat and lost very minimal if any performance.
 
i have a test pipe and my car gained a lot from doing it, can tell it gained power, and yea its smells of exhaust but you wont always smell it unless you have the windows down and a gust of wind blows the exhaust fumes past your window...

But yea its bad for the enviroment and this is def the last car I do that to . My nxt car if im looking for performance then im just going to get a 3in high flow cat... Thats what you should do .
 
not only do i care about being able to breathe healthy and having an ozone for my kids but it will also make a car with a performance exhaust a lot more tolerable noise wise while cruising at freeway speeds if you have a cat on. I have a 3" catco performance cat off of ebay for like 40 bucks and its quiets it down and helps the enviroment.
 
You've all convinced me to go with a high-flow cat. However, I do want to make it so it is not permanent and it is interchangeable. Anybody do this? What will I need and where do I go to get the parts? (Pipes, fittings, clamps, etc.)

Thanks
 
I am going to jump in here on this thread vs. opening a new thread....

My CEL is on on my '96 Talon - took it to Autozone and they said it is code 420 which is bad cat, bad 2nd O2 censor, or a leak. Took it to Midas and they said that the cat is shot (and has blown chunks back to the muffler as well). They want $700 to replace it all, and that definitely ain't gonna happen. Autozone said that a replacement cat is like $120. Is a high-flo cat cheaper, and where can I get one? Hopefully at a local auto parts store? We have Shucks, Autozone, Napa, and CarQuest all locally. My husband welds and has done exhaust on our son's '87 Pathfinder when his cat went bad (his plugged up and the rig ran like CR@P until it was removed), so welding one in won't be a big deal. We just want to do it as inexpensively as we can w/o making it run crummy or sound horrible (a bit louder won't be an issue as it's pretty quiet now). We don't have emissions testing where we are.
 
Support Vendors who Support the DSM Community
Boosted Fabrication ECM Tuning ExtremePSI Fuel Injector Clinic Innovation Products Jacks Transmissions JNZ Tuning Kiggly Racing Morrison Fabrications MyMitsubishiStore.com RixRacing RockAuto RTM Racing STM Tuned

Latest posts

Build Thread Updates

Vendor Updates

Latest Classifieds

Back
Top