Probably right. Too thin and not the best welding job on the side of the box the two pipes go thru. Thicker metal and better welding would have been worth a few ounces of weight.

 

mb230s photos in post 47 really look like an IGA issue. The cracks appear to propagate from the HAZ, heat affected zone, in the weld. If you have a material issue with carbon content and you do a repair weld you still have the same underlying problem. You just created and expanded area of HAZ.

Tom has noted that it appears to be early systems with the problem. If that's the case then maybe Tubi switched their spec on the 304 they were purchasing or their supplier slipped in some higher carbon 304 at one time by mistake. There are over 30 variations of 304 on the market.

I had this problem on a B&B. They blamed the cracks on installation and a warranty was denied. So I removed the muffler cut sections through the welds and had them prepped for micros. What I found was classic IGA in the HAZ which lead to the failure. I got a new muffler for my RSA.

 

Interesting reading on IGA and IGC...well beyond my area of expertise. At this point I don't have much choice but to keep my fingers crossed and hope for the best. Welding was the only option. Muffler is out of it's 2 year warranty, I didn't buy the exhaust, and it doesn't look like Tubi would do anything regardless. I'll send them an email in Italy but don't expect much. I think Tom/Champion was my best "official" option and welding is what they would have done anyway.

There seems to be speculation in several posts from various individuals that the "early" 997.1 exhausts had an issue. I don't know if this is proven. I can only comment on my exhaust and listen to the people who welded it and others who chimed in. It isn't a good exhaust. Material selection and the welds are a problem. I keep thinking about the Chris Farley movie Tommy Boy and the warranty on brake pads.... Several have chimed in already - a 2 year warranty is pathetic.

Maybe I'll do that if it fails again. For now I need the car - it's my daily driver and with winter fast approaching the other cars are laid up for the winter. I'll start watching for an OEM take-off exhaust to have on hand for the next failure. At least it is an easy swap to make.

Thanks for the info. Appreciate it.