Confirm?: Can one universal catalytic converter replace the dual OEM setup? 97 LX

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cwininger

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Confirmed!: Can one universal catalytic converter replace the dual OEM setup? 97 LX

have a leaky front cat. i want to replace it with a single universal weld-on unit, something like this.

i've read a few threads on guys doing something like this, but i cant seem to find definitive info on if this will work without throwing codes. i have a 1997 lx450, so that's OBDII, right? from my understanding, the newer cats perform a three-stage conversion that used to take two separate cats to do (hence the oem setup).

all the manufacturers of these have part numbers for both front and rear cats for the 80's. do i really need two or can i have one welded in and then hook it up with the existing exhaust using a piece of straight pipe? can one handle the exhaust conversion on it's own without throwing codes?

anybody else gone this route? i would love confirmation that this will work fine on my rig. don't want to waste money on the second cat if it's just a redundant part.
 
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Part of the answer depends on your local emissions laws

Here in the Denver metro area, they would look and szee a single cat and fail me. In the rural areas, there are no emission tests or inspections


Technically, the CAT is a pollution device and the vehicle could run without them. Although that would be in violation of federal emission laws
 
cwininger said:
... i have a 1997 lx450, so that's OBDII, right?
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Correct.

cwininger said:
... from my understanding, the newer cats perform a three-stage conversion that used to take two separate cats to do (hence the oem setup). ...
Click to expand...

Also correct. Lots of rigs run single cat here, without setting code.

Romer said:
Part of the answer depends on your local emissions laws
...
Click to expand...

Yep, check your local laws, emission requirements. Here, on OBDII rigs, there is no visual inspection, no code = pass. They only pressure test the fuel cap, vapor system and read the ECU. They don't open the hood, look under the rig, run it on the rollers, nothing.:cool:
 
i live in michigan. no tests, no inspections, no stickers, no nuthin'. it's the home of the motor city- your rig could belch pure cyanide out the rear and nobody would say "boo". i guess my question is answered. thanks guys!
 
Yup, just to confirm, I went to a locally owned muffler shop, NOT A CHAIN STORE, and they set me up with a single cat, mounted horizontal for extra clearance. Ox sensors still in "before and after" positions. Works fine, and no codes. And, like Tools said, for Arizona, no smog problems. John
 
I have a bad cat on my 95 and it looks like I wont be able to go to single. When I go to emissions they do an inspection underneath, open the hood and do an idle test, even though my truck is one of the full OBDII 95's.

Here is a word of caution to everyone. Last year was the first time I didn't tell the inspector the truck is full time four wheel drive when I took my truck to the test facility by the airport in Chandler. I had pointed this out to them the previous times and got attitude so I figured oh well, these guys do this all day long and have seen this type of truck before. Well, I am on my phone looking the other way when I hear my engine revving turn around to see my truck climbing over the chocks and out of the rollers. The tech s*** his pants and I learned a lesson.
 
I'm located west of St Louis, so were required to meet the Gateway Clean Air Act emissions regulations. I replaced my ratteling OEM cats with a CatCO single cat over a 8k miles ago. No issues.

The local shop recomended them versus Magnaflows on my 96 because they have had issues with first generation OBD II and the magnaflows passing emmisions after the first year.

The total install price, including rerouting my exhaust over the frame was 255.
 
I'm in Michigan as well and no emission testing is pretty nice sometimes. I also have one cat and I replaced both O2 sensors when I did the exhaust, no codes yet and both front and rear voltages have been well within spec.
 
Here's where i ended up. bought the magnaflow 99006HM universal cat at auto zone for $88. had a local shop cut off both original cats, fab up a straight pipe connection, and weld the new cat on to the exisiting exhaust. they charged me $105, including the straight pipe and a patch on another leak i had.

i've driven about 200 miles on it since the new cat. everything seems fine, no codes and it sounds good. funny thing about fixing exhaust leaks- fix one and it just makes other ones more noticeable...

anyway, for those of us who don't have emissions testing this seems like a great, cheap way to fix those leaky oem cats. i'm pretty sure this thing would pass inspection anyway, at least on the testing phase.
 
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wfd175 said:
I'm located west of St Louis, so were required to meet the Gateway Clean Air Act emissions regulations. I replaced my ratteling OEM cats with a CatCO single cat over a 8k miles ago. No issues.

The local shop recomended them versus Magnaflows on my 96 because they have had issues with first generation OBD II and the magnaflows passing emmisions after the first year.

The total install price, including rerouting my exhaust over the frame was 255.
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Hey wfd175,

I have a 95 (127K) just recently diagnosed with a bad cat P0420. I'm in St. Charles, MO. Where did you take your truck?

Thanks!
 
If you were to do your own exhaust work and perofrm the cat replacement job in your garage, what does one do with the two oem cats? Can they be sold to someone?
 
We run a single larger high flow cat in our FZJ80 exhaust system that replaces the stock setup and it's worked great. Exhausts : EMSPowered

As Beno mentioned, you'll need to check with your local smog authorities to see if it is legal or not in your particular area.

alia176, most metal recycling facilities will pay you for your used catalytic converters.
 
update: don't recommend this route

so it's been a couple of months since i had the job mentioned in the opening post done. although the new cat is working fine (no codes whatsoever) i've figured out that this was not a great idea.

here's the issue i've run into. i had the flanges on both ends of the cat cut off and the new one welded on. well, now i have a cracked y-pipe. after searching the forum this seems to be a very common occurence, especially for cruisers in the rust belt. the metal is pretty thin, and i'm not sure there's much left to work with to repair it. even if it's repairable it's going to be a temporary fix at best.

now i'm in a situation where probably need a new y-pipe, but it seems like most aftermarket y-pipes come with the cat included, like this one. now i have no flanges left to hook something like this up. not to mention the $180 i have into the new cat and labor on what i already have.

so my conclusion is this: if you need a new cat and don't want to pay top dollar for the outdated OEM stuff, i recommend just replacing the entire y-pipe/catalytic converter set-up using one the Bosal direct-fit replacement for around $200 plus labor. you'll end up saving money and hassle in the long run.
 
has anyone ever done this in cali and passed smog?
 
I was throwing the P0420 code and decided to go with the single cat set-up like the others in this thread have mentioned. I bought the Magnaflow 99006HM for $89 and had a mom-and-pop muffler shop weld it on for $75. CEL was cleared and it passed inspection 30 miles later. So anyone on the fence about this my experience has been great so far.
 
js93cruiser said:
has anyone ever done this in cali and passed smog?
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Howdy! I did this on my (new to me) rig a year ago. It passed smog in Arizona, as it is OBD II, which only requires that they plug it in to the computer, without a visual. No codes equals no problems. I passed just fine, and in over 12,000 miles it has not popped a code yet. I like it. John
 
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