Catalytic Converter

[90 Silverado]

You must be registered for see images attach

You must be registered for see images attach

If you got one of these, get rid of it. It has multiple layers of sheet steel inside with small cheese grader like holes in it. And of course, many tiny round platinum pellets.


Doug in P.R.

 

[PlayingWithTBI]

Yeah, those pellet style converters are quite restrictive. Plus they're only 2 way where the newer ones are 3 way which helps reduce NOx too.

 

[PlayingWithTBI]

Here's some high flow Cats you may be interested in.

https://www.amazon.com/s?k=thunderbolt+2.5+catalytic+converter&ref=nb_sb_noss_2

 

[alpinecrick]

I took the gutted cats off my 98 Tahoe. Jegs has an offroad intermediate pipe thats 100% bolt on. Before I couldn't spin the tires, after it would smoke both of em. I put spark plug non fowlers in, check engine light hasn't come on. Where I am, technically has to be on for inspection, but no ones cares anymore. Long as everything works and is safe, and no check engine light on, they don't care.

Going from gutted CATs to a straight pipe found enough new horsepower to spin the tires when gutted CAT's wouldn't?

mmmmmm........

 

[Frank Enstein]

Honestly havent noticed anything wrong with it but figured i would replace it as the truck has over 179,000 miles on it and it was mistreated by the former owner. But hell if it aint broke then dont fix it huh?

Exactly! Catalytic converters are immortal unless you murder them. The most common failure modes are;
Over-fueling caused by a lazy upstream O2 sensor, fouled plug, bad plug wire and etc. O2 sensors generally begin to degrade after 50 to 80 thousand miles. I only worry about the upstream sensors. the down stream sensors are there to report on converter efficiency.
Burning oil.
Coolant leaks into the exhaust.
Impact Tree stumps, accidents, curbs and such.

If the old cat died find out why or the new one will too.

 

[Frank Enstein]

Going from gutted CATs to a straight pipe found enough new horsepower to spin the tires when gutted CAT's wouldn't?

mmmmmm........

Gutted cats can cause turbulent flow. You generally make more power before you gutted your non-clogged cat.

 

[east302]

The original GM ones are actually worth money if the honeycomb is intact. I checked locally and no one would buy them for more than scrap price (guess they thought they were stolen since I taken a sawzall to the exhaust). I sold the pair to an online group for $270 with “free” shipping. Could’ve probably gotten more if I could have gotten a local recycler to buy them.

Don’t just chunk them in the trash without checking around, in other words. Something to keep in mind.

 

[88monteSS]

I don't recommend it. It's a $10,000 fine to remove it Federal Law. When to check engine light goes on it may put you in Limp Mode and it will run poorly. My 2003 Chevy truck had 453000 miles on it when I sold it and it had the original cat.
Is it running bad?
If it's just the cat and the upstream pipes are good the APH-608227 ($155.99 @ Summit Racing) is a legal cat for your truck.

Same. One of these days the epa is going to start cracking down on people that removed their cats. Think they're expensive now? Wait until a bunch of people who removed them have to replace them to be able to register their vehicle. Plus a modern high flow cat really doesn't sap that much power.

BTW, I don't believe there is a federal law about this. At least here in the State, only the densely populated counties check for emissions. Otherwise state inspection is just a safety check (no emissions check.) Different states have different requirements. Some states don't check emission altogether, while others are really strict.

There is, it's against federal law to remove any emissions equipment, it's just rarely enforced against individuals. If you've seen anything about the rpm act lately that's because once again the epa is trying to remove the off road exemptions that as I understand it have been more of a gentlemen's agreement than actual law. Rpm act would clarify that it's legal to remove emissions equipment on a dedicated race vehicle. Blame the people that buy all the parts labeled as off road use only & stick it on their road driven cars, along with the diesel dorks that intentionally tune their trucks to roll coal for why the epa is trying this again. Honorary mention goes to the companies that name their products things like "the polluter"

Just on cats, usually the feds go after the shops that are willing to do the work for you, which is why it's hard to find a shop that's willing to remove the cat & replace it with a straight pipe.

Sent from my XT1254 using Tapatalk

 

[b454rat]

I had to fix a lot of weird stupid fixes when I bought my Tahoe. One cat was gutted, the other cut off n replaced with a straight pipe. I unbolted the pipes, replaced with the jegs, and got a huge improvement in low end torque, and lil top end. Light would come on after driving on highway then idling. 4 new O2 sensors the rears with the non Fowler’s. In my case made a difference. NYS is second to Commifornia to emissions. They don’t go after cars they go after the garage that took them off. And like I said, they pretty much don’t give a ****. Maybe down state, but thankfully far away from that hole.....

 

[Erik the Awful]

My truck came straight-piped and clogged with mud, so I bought a pair of cats from Summit. They don't list the cats I bought any more, but these are only about $15 more. Note that these are 2.5", your exhaust size may vary.
https://www.summitracing.com/parts/flo-2000125