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Facts and Opinions about Catalytic Converters. by Pontiac Fan 89
Started on: 12-17-2019 01:46 PM
Replies: 17 (655 views)
Last post by: Patrick on 12-22-2019 02:33 PM
Pontiac Fan 89
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Report this Post12-17-2019 01:46 PM Click Here to See the Profile for Pontiac Fan 89Send a Private Message to Pontiac Fan 89Edit/Delete MessageReply w/QuoteDirect Link to This Post
Hi everyone. Purchasing my first Fiero soon, really excited. Put down a deposit with the owner and picking it up when the title comes in.

I have read a few of the ancient posts about catalytic converter removal/replacement, and would love your guys input on the topic. I'd like to lay out all of the previously mentioned issues and questions regarding catalytic converters in one post for future reference. The reason I'm asking is because I will likely need to go through the entire exhaust on my 86 SE, from the headers down. At best, a few inserts of new piping and at worst, an entire new system is necessary.

So, my main question is, should I do one of three things:
-Cut out the cat when patching/replacing exhaust
-Keep the cat if its not clogged when patching/replacing exhaust
-Install an aftermarket high flow or oem new cat

Question 1: Obviously cutting out the cat will negatively impact the cars emissions. I've heard that cutting out the cat can actually slightly reduce engine power. Is this true? On older smog era cars I know for sure that cats play a role in reducing flow. Does the Fiero suffer from this as well?
Question 2: If the cat is shot, is it worth buying a high flow, staying oem, or removing it?
Question 3: Should I even attempt to repair an exhaust that is disconnected from headers down or should I look for an entirely new system?

I'm really excited to start working on and driving my Fiero! It's one of my favorite parts of automotive history and has been one of my dream cars for a while.

------------------
1980 Honda XR80
1975 Oldsmobile Delta 88
1986 Pontiac Fiero SE

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Patrick
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Report this Post12-17-2019 02:04 PM Click Here to See the Profile for PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Pontiac Fan 89:

I have read a few of the ancient posts about catalytic converter removal/replacement, and would love your guys input on the topic.


Lots of current threads. Here's one from two weeks ago - Catalytic converter delete

My opinion... install a new cat. Inexpensive, and non-restrictive.
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Pontiac Fan 89
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Report this Post12-17-2019 02:32 PM Click Here to See the Profile for Pontiac Fan 89Send a Private Message to Pontiac Fan 89Edit/Delete MessageReply w/QuoteDirect Link to This Post
Thanks Patrick!
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cvxjet
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Report this Post12-17-2019 04:25 PM Click Here to See the Profile for cvxjetSend a Private Message to cvxjetEdit/Delete MessageReply w/QuoteDirect Link to This Post
The Fiero V6 cats are a honeycomb matrix- non-restrictive....I doubt if you would notice any difference either way by removing it...just stinkyer exhaust. I have an F-body 3.4 long block under the original '85 induction system. I lost the cat back a few years ago....Bought a new one and drove to Hayward to have it installed....after, I could not feel any difference- But I did not try to quantify the situation......

[This message has been edited by cvxjet (edited 12-17-2019).]

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Pontiac Fan 89
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Report this Post12-18-2019 01:00 PM Click Here to See the Profile for Pontiac Fan 89Send a Private Message to Pontiac Fan 89Edit/Delete MessageReply w/QuoteDirect Link to This Post
Awesome, thanks for the info! New cat it is.
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jessesmith121
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Report this Post12-18-2019 01:12 PM Click Here to See the Profile for jessesmith121Send a Private Message to jessesmith121Edit/Delete MessageReply w/QuoteDirect Link to This Post
Being in a Free State (no emissions or safety inspections) like Iowa I have deleted and straight piped the cat in every fiero I have owned. If I lived in an emission state I would have the high flow replacement cat installed. Not sure on the performance difference as the car really isnt a race car anyways (we are talking 140hp on an antique), but it sure does sound much better. I have never thrown any trouble codes related to them. So for me, no issues, better sound, more room when working on things... no downside for me.

------------------
86 Fiero SE 5 Speed - Junkyard
84 Fiero SE 4 Speed- Sold
86 Fiero SE 6cyl 4 speed M19 - Sold
86 Fiero SE 6cyl 4 speed (25,000 miles) - Sold
87 Fiero SE 4cyl 5 Speed - Sold
86 Fiero GT 4 Speed- Sold
88 Formula 5 Speed T-top - Sold
87 Fiero SE 6cyl $ speed swapped - Sold
88 Fiero Formula 5-Speed - Sold
86 Fiero GT 4-speed - Sold
87 Fiero GT 5-Speed - Sold
Countless parts cars

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Falstaff
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Report this Post12-19-2019 11:12 AM Click Here to See the Profile for FalstaffSend a Private Message to FalstaffEdit/Delete MessageReply w/QuoteDirect Link to This Post
I cut the cat off my '86. It runs just fine without it. In Michigan they don't test for emissions so it doesn't really matter. Since the converter is basically under the engine it does run the risk of starting a fire if oil leaks on it.
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Gall757
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Report this Post12-19-2019 05:36 PM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Falstaff:

I cut the cat off my '86. It runs just fine without it. In Michigan they don't test for emissions so it doesn't really matter. Since the converter is basically under the engine it does run the risk of starting a fire if oil leaks on it.


It's true, in downriver Detroit, one more polluting car will not be noticed.
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ChuckR
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Report this Post12-20-2019 07:16 PM Click Here to See the Profile for ChuckRSend a Private Message to ChuckREdit/Delete MessageReply w/QuoteDirect Link to This Post
I agree that removing the old and installing a new is best practice. I know most don't care of environmental impacts but it is a low cost fix for that and the stink of not having one. Being a small car, that stink will work its way into the cabin. The new cat will not harm performance and will make driving the car more enjoyable on ALL the senses. And as a bonus you don't harm the environment around you as much as if you took it off and left it off.
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Patrick
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Report this Post12-20-2019 07:37 PM Click Here to See the Profile for PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by ChuckR:

I know most don't care of environmental impacts...


Most what? People who don't breathe? Do these same people defecate in their drinking water?

It's not like the benefits of a catalytic converter can't be measured. There is nothing to debate. Catalytic converters do indeed reduce toxic gases and pollutants from the exhaust of internal combustion engines.
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Report this Post12-20-2019 07:51 PM Click Here to See the Profile for pmbrunelleSend a Private Message to pmbrunelleEdit/Delete MessageReply w/QuoteDirect Link to This Post
The opinion / rant portion:
 
quote
Originally posted by Patrick:
Most what? People who don't breathe? Do these same people defecate in their drinking water?


Facts:
 
quote
Originally posted by Patrick:
It's not like the benefits of a catalytic converter can't be measured. There is nothing to debate. Catalytic converters do indeed reduce toxic gases and pollutants from the exhaust of internal combustion engines.

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Report this Post12-20-2019 08:28 PM Click Here to See the Profile for PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by pmbrunelle:

The opinion / rant portion:


Kind of short for a "rant", no?

Have a look in O/T political threads for endless examples of actual rants.
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ChuckR
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Report this Post12-21-2019 11:53 AM Click Here to See the Profile for ChuckRSend a Private Message to ChuckREdit/Delete MessageReply w/QuoteDirect Link to This Post
Yes I meant most people do not care. And they dont. they all say words like we need to do something, but that doesn't me "I need to do something" We means someone else.

I said to install a new Cat and keep the stink away, and also not impact the environment as much as you would if you left it off. I guess I didnt explain I meant leaving the cat off would impact in a harmful way? What exactly did you take umbrage with in what I said?
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Gall757
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Report this Post12-21-2019 12:56 PM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
Well, here is hoping that your vision of 'most people' is either incorrect or out of date. Perhaps you should say 'most people that I know'?
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Patrick
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Report this Post12-21-2019 04:37 PM Click Here to See the Profile for PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by ChuckR:

What exactly did you take umbrage with in what I said?


I appreciate that you've personally acted in a responsible manner in regards to retaining a cat... but making totally unsubstantiated claims about others serves no one.

 
quote
Originally posted by ChuckR:

Yes I meant most people do not care. And they dont.

[This message has been edited by Patrick (edited 12-21-2019).]

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Raydar
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Report this Post12-21-2019 05:49 PM Click Here to See the Profile for RaydarSend a Private Message to RaydarEdit/Delete MessageReply w/QuoteDirect Link to This Post
Without having read all of the previous discourse, here is my opinion.
Obviously, a new cat will help to reduce smog and, more immediately, stinky exhaust. I removed the cat from my 88 4 cylinder, and have noticed an increase in exhaust smell since doing that. I would give serious consideration to installing a replacement, except that the engine is going to be swapped before I put too many more miles on the car. So it may not be worth the trouble.
If you care about the environment, and the car is going to be a "daily", then yeah... install a cat. If it's only going to be driven once a month, to club meetings or etc., then I wouldn't bother.

Without a cat, you will notice a bit more exhaust note, but nothing obnoxious. (The best sounding Fiero I ever heard was a cammed 3.4 with headers, an Ocelot system, and no cat.)
People behind you will get the full benefit of all the chemical additives in the gas that the cat would likely remove. (I am old enough to remember a time when gas contained lead, and cars didn't have cats. The exhaust back then was much less objectionable than the exhaust produced by the current exotic lead-free blends. Nobody ever mentions that.)

FWIW... My 4.9 car has a cat, which will likely stay in place. It's plenty loud as it is.
The swap on the Duke car (a 3.4 DOHC) may or may not include a cat. I have both options available to me, but it depends upon what I need to do to package the exhaust system.

------------------
Raydar
88 Formula IMSA Fastback. 4.9, NVG T550

Praise the Lowered!

[This message has been edited by Raydar (edited 12-21-2019).]

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Report this Post12-22-2019 11:34 AM Click Here to See the Profile for Tony KaniaSend a Private Message to Tony KaniaEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Patrick:

Kind of short for a "rant", no?

Have a look in O/T political threads for endless examples of actual rants.



Multiple negatives coming from Patrick's "accounts".

Whahhh.

I run no cat. My 1987 GT sounds and runs awesome.

[This message has been edited by Tony Kania (edited 12-22-2019).]

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Patrick
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Report this Post12-22-2019 02:33 PM Click Here to See the Profile for PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Tony Kania:

Multiple negatives coming from Patrick's "accounts".


Tony, sorry to see you're still not well.



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