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Gutting Pre-catalytic converter ?

35K views 30 replies 9 participants last post by  Loyale 2.7 Turbo 
#1 ·
Has anyone gutted their pre-catalytic converter attached to their exhaust manifold with any success as far as how the engine runs and how many codes it will set ?

I have been getting codes that the cat is failing or out of spec and was going to order a new pre-cat and both O2 sensors but wow those things are expensive ! I want to keep the car in good condition and still get good MPG and I figured someone out there had gutted theirs for racing and I was wondering the result of such a mod on mileage ?

The car has been slowly feeling held back and the MPG has gone down some like a clogged cat but don't want to just throw money at it, looking for any cheaper options.

When the car was purchased I was told the cat was failing but not which one, but after being under the car I can see where a hole was drilled after the pre-cat on the manifold then welded back up, which I assume was done to check the pre-cat.

Slydog
 
#2 ·
You don't wanna do that. It will sound like ass, more than likely throw a code. You best bet, would be to either, buy the pre-cat, buy one used on ebay or junk yard, or buy a header set-up. The header will eliminate the pre cat, but you will have to extend one of the o2 sensors. Otherwise your at the cel deal again.
It will really sound like ass if you gut that pre cat.
 
#3 ·
1fastkia,

Thanks for your honest reply, that's what I was looking for. I have been looking at Catco or Magnaflow pre-catalytic converters and replacing the O2 sensors with 2 new Delphi sensors.

I currently do not have an OBD2 scanner that reads the "live data stream" but will be getting one as I think I would be money ahead to "diagnose" the problem rather than throwing money at it. What range of voltage readings should I be looking for when monitoring the O2 sensors on a 2001 Kia Sephia 1.8L ?

Any tips on the best catalytic converters or O2 sensors for our Kia's ? My goal is to keep the car stock with slightly improved performance and get the MIL light to go off !

Thanks, Slydog
 
#6 ·
Kiazilla,

Kinda what I was originally thinking on gutting the pre-cat at the manifold as long as the the main cat is good but then it would set codes as the sensor is upstream.

I decided thats way too much work for a car I want to keep stock, so I did find a couple new direct fit pre-cats that bolt right up to the manfold but just wanted to know what brand most guys used as I was looking at Catco and Magnalow pre-cats that are direct fit for our cars.

From my research the Magnaflow will typically flow a little better but I was concerned of setting MIL codes as it seems these Kia's are touchy with any mods or non-original parts being used.

I just coded the car out again after clearing the codes a month ago and it had P0422 (cat) and P0128 (temp low) so I cleared the codes and will drive another week while I wait on my new OBD2 scanner with "live data stream" so I can monitor the O2 sensors and the engine temp via the scanner.

Slydog
 
#7 · (Edited)
I need to make sure we're talking about the same object. I need an item as illustrated here:

2003 kia spectra: converters..pipe..Repair shop is tell me..manifold - JustAnswer

What I see on ebay is not the item I need (a precat) but what appears to be 90 degree angle pipe that is bolted (removable) between the intake manifold (precat ?) and catalytic converter and has the sensor attached to it. It was damaged by a pot hole and is making a lot of noise.
What do you call this thing ?
 
#11 ·
Has anyone gutted their pre-catalytic converter attached to their exhaust manifold with any success as far as how the engine runs and how many codes it will set? ...

I've "Been There, Done That" ... :) ... So I can write about my Own experience.

My Wife's 2000 Sephia runs with a 2003 Spectra engine, with the Original intake & Exhaust manifolds from the Sephia bolted on, as you can read about that, ~► Here: http://www.kia-forums.com/2g-1998-2001-sephia/66863-2000-kia-sephia-engine-replacement-info-4.html


But both Catalytic converters were clogged and since those are not Legally required here, in my Country; I decided to get Rid of them.


Please, see the Followin' Pictures to Understand How I Did that:
 
#12 ·
Here you can see how I Deleted the Second Catalytic converter,

Just use a Straight Pipe instead:





This is the First (or pre-) Catalytic, next to the Exhaust Manifold:




A Closer View:




Even Closer:

 
#13 ·
Here you can see the Catalytic Element inside the Round Box:






I Removed it using a Sledgehammer and Chisel,

Here you can see chunks of it:






It also has some sort of Nest, which was removed using long pliers,

This is How the Empty Box Looks Like:


 
#14 ·
The Car now has a Beautiful Deep Sound, like a Turbo Muffler's Sound but it is Deeper but not any Louder... Maybe Because the Empty Round Box actuates as a Resonator, Somehow.

That Rich Deep sound is with a Common Muffler, not anything Special.

The Fuel Consumption has dropped a little :D

and I have No Codes related to that!


The only code that Lit the "Check Engine" Light, was due to a Low Operating Temperatures: I Run the Engine without Thermostat.

Kind Regards.
 
#15 · (Edited)
I Made a very Short video this afternoon, just to let you Hear the T8D Engine / Exhaust Sound, just follow the Link Below.

~► Here: Kia T8D Engine's Exhaust Tone

The sound is not loud at all, but the Camera's Microphone was very close to the Exhaust tip, which makes you to believe it was Loud.

Warning! ... Doing this could be ilegal in many of the USA States, I am Not giving advice, just answering your Question.

Kind Regards.
 
#16 · (Edited)
For the price, why not just buy a new cat, and not pollute this world?
At less than 75 dollars for a cat, just buy one. Used or online. Plus all our great, great grandchildren still have clean air to breathe.

If everyone in the world took the advise of gutting their cats when they stopped working, the air would be so polluted, everyone would have to wear respirators, or die.

Nice job with the great advice. Pollute the world and make your car louder and sould like crap. Ive done it before, never again. There are no gains from gutting it.


Sorry to be so blunt, but the cats are there to protect us in the future.
Poster, buy a used one.

Im betting your going to disagree with me, but the proof is all their, cats burn the "bad" exhaust gases that create the greenhouse effect, warm the earth, make the air full of crap. Disagree with that.

and from your pics, you not only gutted ONE cat, you totally removed the other.. Great job, now your car has as much smog as a 1960s car. You are releasing 100% of your exhaust into our enviroment. Thanks for that. We all need bad air.

Poster, from me to you, do not do the above here in the usa its illegal to do this in most states, and if you have emmison testing, forget it you will never pass.

And throw a cel.. Im betting.
 
#18 · (Edited)
Well, somehow I Agree with 1fastkia: To the Original Poster is Better Idea to Buy a Brand new Catalytic converter, specially due to Legal Reasons, and pollution reasons...

For the price, why not just buy a new cat, and not pollute this world?...
But for me: it was absolutely impossible to find a brand new Catalytic or pre-catalytic converters here in my developin' country, not even at the Kia Dealer, nor other car brand's dealer, nor almost any aftermarket Store.

Why? ... as I Said:

... those are not Legally required here, in my Country; ...
So even the Brand New cars comes here Without catalytics from factory. period.

Its a Fact that the Same car, made in USA, Mexico, Korea, Japan, etc... will go with a Different setup from factory to the USA Market, than to the Latin American / Asian \ African markets, etc... usually the difference is due to Legal Requirements.

So, almost all the Brand New Cars that comes here thru their Dealers, comes without Catalytics... and other things more or less.

Examples of Different Market's requirements are: the Toyota Land Cruiser II, is has never been available in USA, and we have plenty of them, even with Factory snorkels...






Other example: Subarus does come here (and to the Rest of the World) with Dual Range Transmissions...





...while USA is the only country who doesn't get them since 1992, due to Taxation & Legal Reasons: Due to their Dual Range Trans, Subaru where taxed as "Light Duty Trucks" ...





...which makes them to have a different price to their competitors, and different insurance rate, etc...

So Different Markets got different versions of the SAME car Model.​


Also, here in my country is almost impossible to find a Good Used Catalytic converters... the ones that get removed from cars that comes from USA, usually are Sold to the Metal factories here, they melt them (along all the old metal) to be recicled.



...Nice job with the great advice. Pollute the world and make your car louder and sould like crap...

Sorry but I Didn't gave any "Advice" ... I Was just answering his Question:


Has anyone gutted their pre-catalytic converter attached to their exhaust manifold with any success as far as how the engine runs and how many codes it will set ? ...
So, since I did that, I posted my experience with pics as an Answer to his question, Not as an Advice at all.


...Poster, from me to you, do not do the above here in the usa its illegal to do this in most states, and if you have emmison testing, forget it you will never pass...
I Agree with that.


...If everyone in the world took the advise of gutting their cats when they stopped working, the air would be so polluted, everyone would have to wear respirators, or die...
Well... as I said: Not all the Cars in the World, came or comes with Catalytic converters... also in some countries like Latin America and Europe, there are very much more Diesel Cars than Gasoline cars, even small sedans comes diesel here... those doesn't have catalytics and Diesel does pollute too... even worse.



Your "opinion" is not shared by everyone in the USA... He is located in Honduras and unlike living here and "regulated" to death by bureaucrats who could not find another job to save their souls... He IS free to do what he did. ...

I Agree, Absolutely! :)

Common Sense is the Key words...

One last paragraph: Please accept my Humble apologies to Open such can of worms... that was Not my intention; please don't let me be Misunderstood: I was Not giving any Advice, I was just answering the Original poster's Question.

I will try to Not answer more questions here... However, I will keep Updated my own threads...

Kind Regards & Blessings.
 
#17 ·
Your "opinion" is not shared by everyone in the USA... He is located in Honduras and unlike living here and "regulated" to death by bureaucrats who could not find another job to save their souls... He IS free to do what he did.
I won't go "there" on "Greenhouse Gas" BS.... The "proof" they have supplied is ALL skewed and manufactured to meet "their" needs.

The UK is still standing after all their coal pollution years and their children and grand children are still producing "off-springs". We (USA) need energy NOW and NOT the crap that the current administration is funding... "Our" president is pushing a fuel standard that will END the US car manufactoring industry (55mpg Car/truck/van by 2025)...

We should be burning our coal and OUR petroleum and building more nuclear reactors for our children ...NOT LESS.
We need more common sense and less socialism (government control) in the U.S. not less. I can't even burn the wood from MY fallen tree limbs without some idiot showing up and spouting EPA "standards" and issuing a fine for something nature does all by itself. I'm in a township and not a city and my trees (many) remove more CO2 than one small fire once a year releases.

Like I said "common sense"..
 
#20 · (Edited)
Your "opinion" is not shared by everyone in the USA... He is located in Honduras and unlike living here and "regulated" to death by bureaucrats who could not find another job to save their souls... He IS free to do what he did.
I won't go "there" on "Greenhouse Gas" BS.... The "proof" they have supplied is ALL skewed and manufactured to meet "their" needs.

The UK is still standing after all their coal pollution years and their children and grand children are still producing "off-springs". We (USA) need energy NOW and NOT the crap that the current administration is funding... "Our" president is pushing a fuel standard that will END the US car manufactoring industry (55mpg Car/truck/van by 2025)...

We should be burning our coal and OUR petroleum and building more nuclear reactors for our children ...NOT LESS.
We need more common sense and less socialism (government control) in the U.S. not less. I can't even burn the wood from MY fallen tree limbs without some idiot showing up and spouting EPA "standards" and issuing a fine for something nature does all by itself.

Like I said "common sense"..
Really you? Well, where to start.
Yea our kids and grandchildren are still making babies and some are teaching them the exact things you see above. Now in 100+ years, no we won't be here, but we can do our part, but if the above is done all the time by millions, then see how in some parts of asia air is already barely breatable, it will be like that everywhere with "air" stations" to catch your breath. Thats what I want.


We should be burning our coal and OUR petroleum and building more nuclear reactors for our children ...NOT LESS.
WTF does that have to do with removing a cat? Nothing, the point is, if it came with it why remove it totally. Go remove your tires please.
And what does this have to do with we need energy? the cat has nothing to do with that LOL. Your off point here.

I can't even burn the wood from MY fallen tree limbs without some idiot showing up and spouting EPA "standards" and issuing a fine for something nature does all by itself.
Then move, cause around here, everyone burns campfires. Your neighbor is just an asshole. Still, this has nothing to do with the point I was trying to make. Campfire and Cars emmisions are so different I can't even figure out why you are compairing it. Off point again.

I'm in a township and not a city and my trees (many) remove more CO2 than one small fire once a year releases.
Trees rid the air of co2, there is more in car emmisons than co2.

That once again, makes zero sense of this. I live in vermont, trees outnumber ppl 100 to 1. Forget where I live? VERMONT, more trees than anything. Trees do not rid the air of emmisions. Maybe a tiny bit, but not nearly enough to keep clean air, expecially when the population increases faster than your trees grow. By the time 1 tree grows from acorn to tree, 10 zillions cars have driven a number of miles you could not even count to. For that 1 tree.

There is FACTUAL evidence that the ozone layer is disappearing. A good cause of it is from car emmisions, so you saying there is no facts to suppost it. Is dead wrong. The ozone has holes in it period, its not all from cars, but A LOT OF IT IS.
 
#19 ·
But for me: it was absolutely impossible to find a brand new Catalytic or pre-catalytic converters here in my developin' country, not even at the Kia Dealer, nor other car brand's dealer, nor almost any aftermarket Store.
Im talking ebay and yes almost all sellers would ship to your country. So there are options.

So even the Brand New cars comes here Without catalytics from factory. period.
There is a reason yours obviously did come with one so that is not an excuse. It had one, and you think it doesn't need one. Many other ppl differ this. Not just me.

So, almost all the Brand New Cars that comes here thru their Dealers, comes without Catalytics... and other things more or less.
SAME as above, you took yours off and was to cheap I guess to buy a new one. YOu can get one unlike what you said.
Emmisions of what your car gives off when running is the same as what mine will do here PERIOD. Just because the car is in latin america does not mean its not letting out emmisions, that was a preaty dumb statment by yourself.

Also, here in my country is almost impossible to find a Good Used Catalytic converters... the ones that get removed from cars that comes from USA, usually are Sold to the Metal factories here, they melt them (along all the old metal) to be recicled.
And for a third time, you could get one from lots of USA sellers, dealers, ect. There are buisnesses willing to ship outside of the USA.

So, since I did that, I posted my experience with pics as an Answer to his question, Not as an Advice at all.
You advised him that a cat can be removed and will work fine. No the cat doesn't work removed from the car.
 
#22 · (Edited)
... There is a reason yours obviously did come with one so that is not an excuse. ...
Yes, the reason is that the Car came Used from USA, so is USDM, (United States Domestic Market) not purchased at the Local Dealer, so is not LADM. (Latin American Domestic Market)... and you already knew that.


... Just because the car is in latin america does not mean its not letting out emmisions, that was a preaty dumb statment by yourself...
I Never meant that... and you're Smart enough to Understand what I Meant, isn't it? :rolleyes:



Im talking ebay and yes almost all sellers would ship to your country. So there are options. ... you could get one from lots of USA sellers, dealers, ect. There are buisnesses willing to ship outside of the USA. ...
Yes, but at an Horrid High Expensive Price in US Dollars (Not our Currency) due to the part cost, shipping & Handling plus Taxes... I am facing pretty Hard times here and I have a Family to Feed, so that was Not an Option.


If you really want me to put both brand new Catalytic Converters on my Wife's Sephia, why don't you go buy 'em both new and send 'em as a gift for me?

It is So Easy to criticize, but Hard to Help, isn't it?

Kind Regards.
 
#23 ·
The local liberal fire chief was "problem" and not a "neighbor". He stated I was breaking "Ohio" EPA air quality laws... When I asked him to reference page and number he couldn't. I mentioned this because I'm tired of people spouting what they believe is facts when they are NOT accepted by many thinking individuals.

The facts are as such...Not everyone buys into the junk science of global warming and O3 depletion. The "computer predictions" or "models" have serious flaws..
See...
Stagnating Temperatures: Climatologists Baffled by Global Warming Time-Out - SPIEGEL ONLINE

I also enjoyed ....
List of scientists opposing the mainstream scientific assessment of global warming - Wikipedia, the free encyclopedia

This is where your "experts" take their "facts" from...
Quote " As of February 2012 less than 10 of the statements in the references for this list are part of the peer-reviewed scientific literature.
NOTE--->>>>The rest are statements from other sources such as interviews, opinion pieces, on line essays and presentations. Papers which reject the scientific consensus that human impact on the environment is a major contributor to climate change may account for less than 0.1% of all peer-reviewed papers on the issue [8] (see also Scientific opinion on climate change and Surveys of scientists' views on climate change).
You guys cry "wolf" and then support it with "junk science" and "opinions".

JesZek was fully within his rights to REMOVE BOTH cats as HIS country does not buy into what the US Government laws say.... He's right... your wrong.

CO2 emissions....
Cow 'emissions' more damaging to planet than CO2 from cars - Climate Change - Environment - The Independent
and
HowStuffWorks "Do cows pollute as much as cars?"
This IS a MUCH BIGGER problem than cars CO2 emissions..What do you suggest??? We all stop eating dairy products and eat tofu?

You seem to love government imposed restrictions and taxes imposed on us by only a very small percentage of our population... They only cripple America and infringe upon our rights.

For every so called "fact" you can post I can counter it with scientists using "scientific method" with real "controls" in place.
 
#24 ·
... The facts are as such...Not everyone buys into the junk science of global warming and O3 depletion. The "computer predictions" or "models" have serious flaws...
I Agree!


... I'm tired of people spouting what they believe is facts when they are NOT accepted by many thinking individuals...
Same Here.


...
CO2 emissions....
Cow 'emissions' more damaging to planet than CO2 from cars - Climate Change - Environment - The Independent
and
HowStuffWorks "Do cows pollute as much as cars?"

This IS a MUCH BIGGER problem than cars CO2 emissions..What do you suggest??? We all stop eating dairy products and eat tofu? ...
Maybe some guys thinking the same than him will suggest to put Catalytics on the Cow's... back part... :eek: ...I knew about the Cow's Farts since long ago, I love to Read. :)


... For every so called "fact" you can post I can counter it with scientists using "scientific method" with real "controls" in place.
I Agree.

Well, as I Stated:

... Please accept my Humble apologies to Open such can of worms... that was Not my intention; please don't let me be Misunderstood: I was Not giving any Advice, I was just answering the Original poster's Question.

I will try to Not answer more questions here... However, I will keep Updated my own threads...

Again: Sorry, for Hijack the Thread.

Good Bye.
 
#25 ·
Guts and runs just fine

Well, I hate to break it to you but in reality, both catalytic converters CAN be gutted and the car runs JUST FINE! I know because mine have been gutted for about 4 years. nothing else has blown or gone out as a result.

I started with 65,000 km on this car in 2005, and it now has almost 360,000. I gutted them back in 2007 at about 200,000 km.
 
#29 ·
Update!

This:

... both catalytic converters CAN be gutted and the car runs JUST FINE! I know because mine have been gutted for about 4 years. nothing else has blown or gone out as a result.

I started with 65,000 km on this car in 2005, and it now has almost 360,000. I gutted them back in 2007 at about 200,000 km.
Is True, the "KiaStein" keeps running Flawlessly without both catalytic converters, after more than Five years so far, and still has that nice deep tone on the Exhaust, that I like.

Kind Regards.
 
#26 ·
Had to add my .02 , i gutted mine out of necessity and havent had a problem, Did have a O2 sensor code but just recently cleared the codes and no codes have returned.

Global warming, I believe is bullshit. The data used over a miniscule period of what, maybe 100 yrs, using sensors, which we all know are "perfect" and "last forever" that have been bouncing around in the ocean, and never maintained. Come on. The earth is old as hell and cycles through climate changes.

Now are we destructive and messy creatures, yes.

Are we helping the earth by putting all the trash we make everywhere? No!

Honestly we are past the point of no return. And if anyone thinks differently, you're just a hippie dreamer. Majority of people are ignorant and just dont care.

Take a look around, were doomed LOL.

Were just here for the ride, so enjoy!
 
#27 ·
As I said before if "Mother Nature" doesn't like us..."She'll get rid of us".
Life (and the earth) will go on with or without humans.
Tides rise and fall.
Temperatures rise and fall.
Cold ages have come and gone.
Tempers rise and fall.
and man will rise and eventually fall
That's life..

We are consumed with what we "believe" the "experts" spout.
Who gave them the "expert" labels and where is their "long term" evidence?
Models... Computer models... based on hearsay and possibilities.

One article I read compared/charted the relative increase in temperature on mars and earth from the sun's varying energy output and they MATCHED in increases and decreases over time.

The continent of Africa WAS lush flat lands 10k years ago and is now desert
It will be fertile land again.

BTW... Our "trash" will be future generations "resources" and our claims to "doom" will be our folly in history.

The atoms on earth from a million years ago are still here...Just "recycled".
Dave
 
#28 ·
Yes, I Agree with Dave.

About the Catalytics, as I wrote on Previous Posts, also you can see Photos of That: My Wife's Sephia Runs with a Spectra engine without Both Catalytic Converters for Years now; and it Runs Fine.

Also Fuel Consumption dropped a Li'l amout and there is No Odor on the Exhaust Fumes, which by the way are't coloured at all, and Engine Temps are a Li'l Cooler.

You can see it in the Following Videos:


the "KiaStein" on Highway:

~► The "KiaStein" on Highway - Aurora Mountain Park - YouTube


the "KiaStein" = Spectra Engine on Sephia Body, Exhaust:

~► The "KiaStein" T8D Engine's Exhaust Tone - YouTube


the "KiaStein" Offroading:

~► The "KiaStein" Sephia with Spectra Engine, Racing on Unpaved Roads - YouTube


Kind Regards.
 
#30 · (Edited)
The Videos on my Previous post above, are not displaying correctly, because this forums' system adds the "URL" code to the web addresses...

How could I avoid that this forums' system automatically adds the URL code to the web addresses?
 
#31 ·
This mod keeps being awesome and flawless after all these Years!

I've been asked about the Low end Torque, after gutting the pre catalytic conveter and erasing the other catalytic converter:

Kiaboy88 said:
... I was just wondering if you lost any low RPM torque when you did that
The answer is No, the car did not lose low end torque, or at least Nothing that my Butt-Dyno could tell me...


...I mean: I have not tested the car on the dyno nor did other scientific tests, but I can assure you, that gutting the pre catalytic converter and erasing the main catalytic converter, has made my T8D engined kia, even Faster, while gives an Awesome Deep tone to the exhaust, a tone that sounds very deep but not loud, only during hard acceleration, and even during that, isn't very loud; the sound does Not have the typical four cylinder engine's Rasp. The exhaust still has the Resonator and the standard muffler.

You can hear the Exhaust without both catalytic converters, here:



Kind Regards.​
 
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