Catalytic converters

I have Gibson headers on my 2007.

The darn things are a thorn in my side and are impossible to keep tight at the flange where the cat and header meet.

First it was the bolts backing out. Solved that with stage 8 bolts.

But now the flange bracket on the cat side has slowly bent so that no amount of torque will keep them from leaking.

I thought about trying a 2 piece replacement flange but I know it will just be a temporary fix.

I could go back to stock headers but A: I dumped too much money into these already and B: I don't want to go back to cracking headers.

Which brings me to aftermarket converters. I see "performance" cats available for a lot cheaper than OEM replacements.

My question is: Will there be enough back pressure for the 3.8?

The metal seems to be higher quality and I'm hoping will be able to withstand more heat.

I'm also open to other suggestions to get these things to stay tight. It's really annoying to have my jeep farting from the front and mor annoying is the power loss.
 

toxicwaste29

New member
Could you possibly take it to a muffler shop and have them welded. Granted though you couldn't easily remove that section of exhaust anymore.
 

toxicwaste29

New member
If you welded it could you still unbolt the headers from the head then unbolt it further down the exhaust and just slide out the whole assembly. After that cut off the old cat and reweld new ones on. Also shouldn't cats be replaced every 100k miles
 

jeeeep

Hooked
If you welded it could you still unbolt the headers from the head then unbolt it further down the exhaust and just slide out the whole assembly. After that cut off the old cat and reweld new ones on. Also shouldn't cats be replaced every 100k miles
100k miles guess i better get in the mindset if i get any codes. I'm at 112k miles
the stock unit is expensive!
 

jeeeep

Hooked
I'm at the same mileage. Still not quite sure what to do. There's actually more aftermarket options than I thought there would be.

since you're running aftermarket headers I would go with an aftermarket cat may as well try to get the most performance you can
 

taher2.1

Member
You wont pass smog with aftermarket Catalytic converter in CA. Check before you buy

I had the same issue in 2013 and I ended up buying OEM
 

Tigrcky

New member
Just a heads up the cats are designed to last the life of the motor, provided that you don't run really rich all the time and burn oil. And there is really no such thing as a performance cat. I would see about rebending the bent flange.
 
You wont pass smog with aftermarket Catalytic converter in CA. Check before you buy

I had the same issue in 2013 and I ended up buying OEM

There are a handful of CARB compliant aftermarket CATs.


Honestly I'm not worried about it CARB or not. The way I understand it is that the main difference is that if the company paid the state for the cert. According to Magna Flow the CARB ($800) and Non-CARB CAT ($483) is exactly the same, but one has a fancy sticker you put on the car. Plus my old ZJ didn't have a cat and passed evert time.

I can't bend the flange back because it's just going to bend again especially since it's already weak.


I'm still wondering about the back pressure.

Does anyone know if a "free flowing" exhaust consisting of short headers (yes I know that long headers are better), performance cat and a magna flow muffler would be a positive gain?

I'm having a hard time finding information about back pressure with google.
 
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