Inexpensive catalytic converter worth it?

[paulo57509]

Magnaflow makes a universal, weld-in converter. I run a Magnaflow direct fit (CARB approved) in the Legend with out issues.

The original converter started to allow higher than allowed NOx at the 15mph test speed. If it's going to fail, it's going to fail here. The new converter brought the test numbers back down to the low end of "pass" range.

Like some others have posted, I'd try to find a reason why the converter plugged in the first place. Oil consumption is suspect.

 

[zzyzzx]

Inexpensive catalytic converter worth it?

Sure, as long as you don't mind putting in a rear O2 sensor spacer.

 

[ammolab]

You said consumption is a liter every 3500 miles, that may be enough to kill the CAT. Converters don't clog just because they are Hyundai.

Burning oil doesn’t plug the cats…it chemically KILLS them. You get check engine light from the secondary O2 sensor. Clogging the converter is often a melted substrate from misfires or generally running way rich.

 

[kschachn]

Burning oil doesn’t plug the cats…it chemically KILLS them. You get check engine light from the secondary O2 sensor. Clogging the converter is often a melted substrate from misfires or generally running way rich.

Yep. And with no catalyst efficiency code it’s unlikely the problem is poisoning.

 

[97prizm]

The catalytic converter on my 2016 Elantra has decided to clog up. Currently at 135,000 miles, I noticed it was down on power about a year ago but didn't think much of it. Drives alright if you take it very easy. No codes for catalytic failure and there is no emissions testing here. The engine consumes 1 litre/3,500 miles.
New factory converter = $1,500. .Cheapest universal converter = $75. The converter is a simple inline round section with an o2 sensor in the side/middle. I imagine a universal is the way to go. I can find ultra cheap for $75. And magnaflow or eastern for about $200. Can't find a walker that fits the bill.

So the questions.....has anyone had any luck with the cheaper [$100 - $200] converters? I don't want to replace it in 3 months but It doesn't have to last forever.

Any recommendations?

I worked as an emissions Inspector and while your state might not have emissions many newer vehicles are sensitive enough where it can throw check engine lights etc. Unfortunate Colorado now has jumped on board with California emissions compliance.

 

[Silverado12]

"No codes for catalytic failure and there is no emissions testing here."

This is surprising. Progressive leftist Canada?

Bruh, stop with the pRoGrEsSiVE LeFT nonsense.

 

[SHOZ]

You can get a full manifold and cat for under $200 on eBay. Bolt on. Took me 30 minutes in the cold to change a few years ago. Only issue was the OE exhaust pipe flange bolts had round nuts. Had to cut them off.

 

[slacktide_bitog]

Is yours the SULEV model?

Cat warranty is good for only 80,000 miles so I'm out of luck there. There are CARB compliant universal converts available for about $550. Maybe I'll have to go that route. The Hyundai converter is sold as part of the exhaust pipe and resonator [4 ft long] I should call and ask if they sell a weld in converter only. Still looking for options.

This is probably the best way to go.

Get the cheapest CARB cat. California-legal ones have more catalyst material in them and a longer warranty. It should last 5 years or 50k. Federal non-CARB cats only have a warranty for 2 years/25k for catalytic performance

 

[WobblyElvis]

This thread seems to be of interest to many. Still don't see a lot of post by people who have changed many converters.
Vehicle is a 2016 Elantra Gt with a 2.0 Nu GDI engine.

The converter in this case is not part of the exhaust manifold but sits horizontal a couple of feet aft of the manifold/header. The engine does not have a history of setting any misfire codes but...as of recently, when you floor the car and it protests by bogging down and downshifting and producing many small backfires [pops] in the exhaust, you can get it to set a misfire code. I wish my scanner had a current misfire counter.

Fuel trims are within %2 + or -. Looking at the downstream sensor voltage, it moves a little for the first few minutes of operation and then settles in a .6 - .7 volts. This is a little high but it is nice and steady, indicating converter is functional. The upstream O2 sensor jumps around as it should.

Measuring infrared temp gun, inlet of cat to outlet, temp increases maybe 40F, again indicating converter operation.

I find it hard to believe that burning 1 litre oil/3,500 miles could cause a properly built cat to fail this soon. It makes sense that the substrate is somewhat melted and not clogged with oil. Have to mention the car has always returned less fuel mileage than expected as if running rich, but the scanner does not support this.

Although we don't have regular emissions testing here I prefer to keep the car without any trouble codes and I wouldn't like to sell a car with an emissions defect.

This is a second car, so no hurry. I am trying to dig out my cheap borescope and take a looksee inside. Tried to take the upstream O2 out yesterday but it is in such an awkward spot that I need to approach it from another angle. Perhaps better to just throw some money at it.

 

[eljefino]

When I had a cat failure the substrate broke loose and wedged itself sideways, blocking airflow. And I knew it, knew it. Had about 10% of normal power, had to nurse it up to speed.

There is a chance of an efficiency code, FWIW.

If it's legal where you are, I say go for it.

 

[kschachn]

This thread seems to be of interest to many. Still don't see a lot of post by people who have changed many converters.
Vehicle is a 2016 Elantra Gt with a 2.0 Nu GDI engine.

The converter in this case is not part of the exhaust manifold but sits horizontal a couple of feet aft of the manifold/header. The engine does not have a history of setting any misfire codes but...as of recently, when you floor the car and it protests by bogging down and downshifting and producing many small backfires [pops] in the exhaust, you can get it to set a misfire code. I wish my scanner had a current misfire counter.

Fuel trims are within %2 + or -. Looking at the downstream sensor voltage, it moves a little for the first few minutes of operation and then settles in a .6 - .7 volts. This is a little high but it is nice and steady, indicating converter is functional. The upstream O2 sensor jumps around as it should.

Measuring infrared temp gun, inlet of cat to outlet, temp increases maybe 40F, again indicating converter operation.

I find it hard to believe that burning 1 litre oil/3,500 miles could cause a properly built cat to fail this soon. It makes sense that the substrate is somewhat melted and not clogged with oil. Have to mention the car has always returned less fuel mileage than expected as if running rich, but the scanner does not support this.

Although we don't have regular emissions testing here I prefer to keep the car without any trouble codes and I wouldn't like to sell a car with an emissions defect.

This is a second car, so no hurry. I am trying to dig out my cheap borescope and take a looksee inside. Tried to take the upstream O2 out yesterday but it is in such an awkward spot that I need to approach it from another angle. Perhaps better to just throw some money at it.

From what you’ve posted the converter is plugging, but you haven’t confirmed that have you? If that’s true, that’s an entirely different problem.

 

[cjcride]

"No codes for catalytic failure and there is no emissions testing here."

This is surprising. Progressive leftist Canada?

Ontario dropped emission testing

 

[WobblyElvis]

Installed a new inexpensive cat. Power is restored and everything is fine....for now. I saved the old converter and did a little poking around in side of it. Can someone explain to me what this crud is? Most of it chips off easily with a pic and the substrate underneath is in tact. It's gritty like stone or minerals. Removing it does not unblock the cat. It's restricted or blocked down many of the tiny holes.

 

[GMBoy]

I believe your cat would be covered under the federal mandated emissions warranty. Hyundai covered the cat on my 99 Elantra when it was a few years old, no charge.

THIS - the mandated federal emmisions warranty is 8yr/80k miles for converters

 

[WobblyElvis]

Please see post #6.

 

[researcher]

Installed a new inexpensive cat. Power is restored and everything is fine....for now. I saved the old converter and did a little poking around in side of it. Can someone explain to me what this crud is? Most of it chips off easily with a pic and the substrate underneath is in tact. It's gritty like stone or minerals. Removing it does not unblock the cat. It's restricted or blocked down many of the tiny holes.View attachment 188691View attachment 188692

first.. glad to hear you got a new catalytic and it was inexpensive! ok onto the odd stuff..

At first I thought it was carbon but that's not that color.. Then I ran across a picture of the matting surrounding the honeycomb brick called "Vermiculite".. and it has the appearance of what you see in your picture. If that were to break down and come loose it definitely would block the air flow to the honeycomb structure. Others may have a better explanation but my guess is the Vermiculite matting broke free and got into the air flow, I don't know how.. maybe cheap quality or overheating (car running rich)? Here's a picture of Vermiculite

and here is a diagram showing it in a mat around a catalytic, the honeycomb is called the substrate.

hope that helps.. best I could find..

 

[2strokeNorthstar]

CARB replacement cats are required to have a 80k 8 year warranty. I just replaced the drivers side 2 with a bolt in Catco. About $600, installed myself. The year,make,model, even vin, makes a big difference in price.

 

[WobblyElvis]

Researcher...
I think you are on to something. I'll see if I can look inside over between the sidewall and the substrate. See if anything is missing. This material is only at this one location, at the very front inlet side, not in between the two catalytic structures. Odd you would think the flow of exhaust gases would push the vermiculite back to the center section or out the back of the converter.

 

[Nukeman7]

Get the cheapest CARB cat. California-legal ones have more catalyst material in them and a longer warranty. It should last 5 years or 50k. Federal non-CARB cats only have a warranty for 2 years/25k for catalytic performance

There is a hidden "catch" to redeeming the CARB compliant warranty. Before purchasing my replacement cat., I spoke with Walker Exhaust and Magnaflow about buying a CARB compliant cat. with the longer warranty for my Honda which resides in a non-CARB state (Virginia). Both companies advised me to buy the cheaper non-CARB compliant cat. because redeeming the 5 yr./ 50K mi. CARB warranty requires producing a failed emissions test certificate from a state which adheres to CARB emissions standards (e.g., California, Washington, Colorado, etc.). The warranty is not honored for vehicles registered in a non-CARB state.

 

[JWC86]

For places without emissions testing, are their ways to trick the computer and just run a strait pipe rather than a cat?