Wow,... Cats DO make a difference

Having recently failed an emission inspection I installed a new catalytic converter. Not that I know what the numbers mean but I can interpolate and the following applied in my case: The maximum state standard for Oxides of Nitrogen emissions is 2.6 GPM. Mine failed at 3.37 GPM. After I installed a new hi-flow cat with no other modifications, I was down to .20 GPM. I'm very impressed.

When I removed the old cat it sounded like the entire insides had fused into one molten rock that was rolling around inside a tin can. The only reason it got that far down death row is because 1) I was oblivious to the problem and 2) the people at the inspection station could never maneuver my 5-speed on the dynomometer test and it would always abort the Jeep so they had to pass me. Finally I got caught but glad I did. The XJ even runs better now.

yardape said:

Mine failed at 3.37 GPM. After I installed a new hi-flow cat with no other modifications, I was down to .20 GPM.

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Yep. And modern catalytic converters, especially the high-flow type, do not reduce your power or gas mileage to any measurable extent. Which is why it is really kind of stupid to run without one.

they cost how much and you got it where?


I would like to completly re-do my exhaust (factory stuff) I dont want any rumble or noisy shit on my truck, just quiet smooth, no noise, etc.


L.R.

This one I picked up from Rusty's but I know you can get them for less elsewhere. Rustys' is not a stock system and if you want quiet you should stick with a stock setup.

You should also replace your O2 sensor and check for any other emission system problems. Cats don't just go bad, something caused it to melt down. My 91 with 225k miles still has the original cat and it works fine, just looked in there a few weeks ago and it still looks clean and clear. If it melted you've got other problems.

and new cats cost? whole new exhaust from manifold back costs?




o2 sensors cost?


L.R.

I've been using Catco direct fit cats from Summit Racing. First one, several years ago, cost around $60 IIRC. Most recent was $79.95. Summit now also carries a second brand that's a few $$$ cheaper but since I've been happy with the Catcos I'll probably stay with that brand. (Foolish consistency and all that stuff ...)

eagle,
did you notice any difference in performance or gas efficency?

Bradlybob said:

You should also replace your O2 sensor and check for any other emission system problems. Cats don't just go bad, something caused it to melt down. My 91 with 225k miles still has the original cat and it works fine, just looked in there a few weeks ago and it still looks clean and clear. If it melted you've got other problems.

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Exactly and it's most likely running too rich because of a bad coolant sensor and or a bad o2 sensor as stated above.

JoBo

LoneRanger said:

they cost how much and you got it where?


I would like to completly re-do my exhaust (factory stuff) I dont want any rumble or noisy shit on my truck, just quiet smooth, no noise, etc.


L.R.

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AutoZone has universal high-flow cats for $80.00. I just put one on my rig and it definatly made a difference. After running it without one for four years, I will never go without one now.