Finally got around to chasing down my squeal noise and found an exhaust leak that I believe is smack dab in the middle of the 4 to 1...
I've been to one muffler shop that said they wouldn't be able to repair it, something about crystalized metal welding something I didn't understand.
If someone can explain if that was code for, they didn't want to do it, or if it's a real problem...
I will try some more shops tomorrow but hoping for some input from others who have swapped these.
I'm in Colorado emissions area so looking for help on either repairing this or getting something new that will pass the sniff test, I don't know if something like the Miltek w/ high flow cat would do that?
The OEM ones are like $3,000 so that's probably out, but I will probably post a wanted in the marketplace.

 

I can't comment on the welding concern, but I will say that my Scorpion header does not throw any codes like I've heard the Milltek sometimes does. However, the volume did increase a bit, I assume due to the Scorpion's higher flow cat.

 

I saw an add on the internet for something called strong foundry glue , and it was used for many different tasks including exhausts. You mix it and glob it on. Maybe that would take care of your issue.

 

Interesting.
Although, I'm just a hobbiest when I comes to welding - I never heard of "crystallized metal welding" apparently, it's a real thing (I guess we learn something everyday?).
To BRGPA''s comment about that product mentioned; I have to wonder if it is similar to JB Welds "ExtremeHeat" super high temp Epoxy paste.
I used it a couple of times on my R53 factory exhaust manifold at the joints between the flex pipe and also the CAT where I'd thought there was a break.
The stuff (JB Weld), seemed to work really well as indicated up to 1,000°F continuous heat.
If you decide to try it and then decide to have it welded - the intense heat from a welder should burn off any remaining product. So there'd be no harm in trying.

 

Interesting, I might try the JB weld route. I've also seen maybe braising will work...
Anyone have experience with the Magnaflow? Seems like the only "CARB compliant" option, was hoping something like the Miltek would be good enough to pass the rolling sniffer but haven't seen anyone with results on that.

 

I looked at the specs for the strong foundry glue and it would appear that the high temp JB Weld would have a higher temperature rating than the strong foundry. That would seem like something to consider if you'd like to DIY before sinking $$$ into replacement.

 

With respect to either the Magnaflow or Miltek CAT (?) - I can't really comment on either. I run the stock/factory R53 manifold exhaust. However when my original factory CAT finally internally broke, I searched for a reliable replacement that was California CARB compliant. I was wary of the cheap eBay ones but tried to research a Magnaflow that would fit a first gen Mini that I could have welded in replacement of my factory one. Try as I might, I could not source any confirmation that the Magnaflow would pass smog inspection in all 50 states.
You might have better luck. Hopefully someone here on NAM from Cal will chime in with confirmation.

​​​​​​I wound up (lucky enough), to get a first gen manifold with CAT from a contbutor here on the NAM forums.
I still can't help wondering if the performance Magnaflow CAT would've been a safe bet?

 

Managed to go around to another shop and get an opinion, much more positive.
They cut internally welded, put it back together and externally welded, no more leak.
Hope the welds hold, they seemed pretty confident that the repair was easy and would last.
Pressure tested it when I got it home and it holds so fingers crossed.

 

Fantastic.
"Never say "can't" - in my book.
Glad you found someone with the nads to have a different perspective and get the job done.
Hope it holds for a long time to come.

 

Good Job !

 

looks like it will do the trick to me

 

Great!