What would cause a muffler to "blow out?"

[ghunt81]

So I mentioned in a post a few days ago about how I had noticed a "rasp" to my exhaust at WOT that I didn't remember hearing before.

Today I drove up to Carlisle for the Ford Nationals, I noticed on the way on the highway that there seemed to be more noise and drone inside the car than I had recalled before. After I got there I put the windows down and noticed the car was definitely louder.

When I went to leave I started the car and walked behind it, and the volume of the driver's side muffler was definitely louder than the passenger side muffler. Maybe today's trip made it worse but I noticed on the way home that the car just seems loud as hell now. I'm guessing some of the packing blew out of it.

This is a Ford Racing-badged Borla Touring axle back that I bought used last year, ran all last summer and never had any issues. What would cause a several year old muffler to just suddenly do this?

 

[oldVOR]

Those are all stainless and won't generally rust out but aren't impervious to rusting. Winter chemicals can and will cause automotive stainless to rust.

Check the welded points on the muffler can and then the connection points of the pipe to the can.

More than likely, you have a split seam or broken weld that wouldn't necessarily be big enough to allow the stainless packing material to come out of the muffler. If this is the case, any welder proficient with stainless can weld the area back together.

 

['14StangGT]

I think you just nailed it.

Years ago, I had a Magnaflow that became louder after a couple of years.

 

[ghunt81]

Wouldn't the extra noise be coming from somewhere besides straight out the tip, though? Because that's where I noticed it was louder, right at the back putting my ear closer to the tips on both sides.

I will check it out next time I have a chance though. I don't drive this car in the winter and everything looked pretty good when I had them off the car over the winter while it was in storage.

 

[86GT351]

Wouldn't the extra noise be coming from somewhere besides straight out the tip, though? Because that's where I noticed it was louder, right at the back putting my ear closer to the tips on both sides.

I will check it out next time I have a chance though. I don't drive this car in the winter and everything looked pretty good when I had them off the car over the winter while it was in storage.

That is just the point where the exhaust comes out so that is where you hear it. If a Muffler actually came apart then you would hear it at a different location. Possible the baffling inside the one muffler has come apart somehow. This will obviously cause a noise difference side to side.

 

[ghunt81]

I'm actually thinking now that the over axle pipe may have pulled part of the way out of the muffler inlet. I've been having issues with the over axle pipe contacting the axle when the suspension almost bottoms out, and I bet that's what happened here.

 

[86GT351]

Possible.

 

[ghunt81]

I just went out and looked at it and yeah, that looks like what happened. I can see one of the slits in the muffler inlet sticking out about 2" past the edge of the clamp. Whoops

 

[86GT351]

That will cause it.

 

[oldVOR]

Every time....