To replace the pellet Catalytic converter or not?

[studigggs]

I have a 1990 5.7L @160k miles with the original pellet cat still on it. I still pass emissions and am satisfied with the way the truck scoots around. I would like to ask those that have swapped out for a newer honeycomb cat if you noticed an increase in pep, MPG etc? I have a newish Walker cat-back system on there and the engine is completely stock. I'm in California, so I'd have to buy the CARB version which adds $100. Just trying to justify/motivate the purchase if it happens to have any noticeable benefits. Thanks in advance.

 

[Schurkey]

I removed the pellet converter from my '88 in favor of a "universal" honeycomb cat.

I did this during an engine swap. The entire OEM exhaust system was scrapped. Reinstalled with Edelbrock Tubular Exhaust System "headers", the honeycomb cat, and a Flowmaster 3" cat-back exhaust system 'n' muffler.

The truck had a little more power, and about a mile-per-gallon better economy--but how much of that was the new exhaust, and how much was replacing the tired 230,*** engine I couldn't tell you.

I was glad for any improvement...but...I had hoped for more.

 

[PlayingWithTBI]

I removed the pellet converter from my '88 in favor of a "universal" honeycomb cat.

I did the same in my 88 because the old one rattled when I shook it. I went with this converter but, it probably won't work in CA, may not work here either, I'll find out in Sept 2020, LOL.

https://www.amazon.com/Thunderbolt-...way&sprefix=thunderbolt+catal,aps,2069&sr=8-3

 

[studigggs]

Thanks for the input. I went ahead and swapped out for a honeycomb about a month ago. I think i can feel a little more power. If nothing else, I trimmed 20 lbs off the curb weight. That pellet cat was heavy.

 

[Donald Mitchell]

No doubt, those things were heavy!

 

[PlayingWithTBI]

Keep in mind the old pellet style converters were considered "1 way" cats (which were restrictive too), the newer ones are "3-way" which helps control, not only COs, but NOx (EGR). NOx is probably what will cause you will fail in CA. As usual, the general liability clause applies, lol.

 

[Supercharged111]

Pellet cats make good mufflers. I ran with no muffler on my 88 and it was mellow.