Advice on Catalytic Converter for 97-98 2.5 Four-Banger?

SSTJ

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Any other owners of a 97–98 2.5L four-banger have any advice to share about the catalytic converter? I think the 97 and 98 2.5s had the same catalytic converter, and only had the one. Right?
  • Around how many miles did yours begin to cause trouble?
  • If replaced, did you go with an aftermarket or get a local shop to do it for you?
  • If replaced, what else did you do at the same time?
  • And of course, how much HP did you gain in the process? ;-)
 
Pretty sure I am on my fourth converter the first failed right after I bought my SE with 89000 on it. Since I do not have to worry about CA emissions I use a Dynomax universal cat and weld an O2 bung into it. Even though the universal cat arguably flows more CFM than the stock cat do not count on gaining any power from it I do it because it is the most economical route.
 
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Pretty sure I am on my fourth converter the first failed right after I bought my SE with 89000 on it. Since I do not have to worry about CA emissions I use a Dynomax universal cat and weld an O2 bung into it. Even though the universal cat arguably flows more CFM than the stock cat do not count on gaining any power from it I do it because it is the most economical route.

Thanks. So, if you're on your fourth, does that mean that the Dynomax doesn't last?
 
Thanks. So, if you're on your fourth, does that mean that the Dynomax doesn't last?
Two things that work against these. First is there is a solid connection to the head pipe so all the engine vibes are transmitted to the cat. This is not too big a deal it just means that cats do not last as long on the four poppers compared to the six. Second specific to me is I do a fair amount of cold water crossings so they suffer from thermal shock.
 
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Two things that work against these. First is there is a solid connection to the head pipe so all the engine vibes are transmitted to the cat. This is not too big a deal it just means that cats do not last as long on the four poppers compared to the six. Second specific to me is I do a fair amount of cold water crossings so they suffer from thermal shock.

Gotcha. Good to know about these not lasting as long on four-bangers.

For someone like me, who cannot weld an O2 sensor in place, do you have any recommendations for other catalytic converters?
 
That one does not have an O2 bung though.

Yikes, thanks. But I wonder why the one you linked showed as not fitting my 97. I'll have to look; I wonder if the 02 sensor is in a different spot on the 97s. Always possible ...
 
Yikes, thanks. But I wonder why the one you linked showed as not fitting my 97. I'll have to look; I wonder if the 02 sensor is in a different spot on the 97s. Always possible ...
Their head pipe kit shows the bung in the tube and not the cat.
 
You should have two. The upstream one just after the manifold and the downstream one just after the cat.
You should have two. The upstream one just after the manifold and the downstream one just after the cat.
You are correct. I understood the conversation to be about the sensor between the manifold and cat and was referring to that one specifically. I should have stated that better.
 
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You are correct. I understood the conversation to be about the sensor between the manifold and cat and was referring to that one specifically. I should have stated that better.

Yep, thanks. We were trying to figure out why the Magnaflow catalytic converter for my 97 didn't have a downstream O2 sensor on it.

I just had a look, and my downstream sensor is right in the middle of the short length of pipe between the cat and the muffler. So I reckon that's why the 97 SE Magnaflow doesn't have one.
 
Revisiting this topic again today. Bumping the thread in case others have advice to share on any of the four questions in the original post.
 
How much HP did you gain...hahahahah....its a 4 banger and if you ever thought letting it fall off all by itself, DONT. What you'll gain there if its a softop or topless is lots fumes and a eventual headache. DAHIK.
 
How much HP did you gain...hahahahah....its a 4 banger

Yep, I know. Hence the wink in the OP.

How much HP did you gain...hahahahah....its a 4 banger and if you ever thought letting it fall off all by itself, DONT. What you'll gain there if its a softop or topless is lots fumes and a eventual headache. DAHIK.

Sounds like you've been down this path before. What did you choose for your replacement and how did it go?