E34 535i MUFFLER GUTS

[Dash01]

Has anybody cut open a stock Ebers/Boysen rear muffler to see what's inside and how it's designed?

If so, what did you find?

Given the high cost of replacement mufflers, I'm wondering if they could be rebuilt by opening the can and replacing whatever is faulty, then re-welding. The local high school metal-shop class teacher said they would help, and have lots of proper equipment.

[Jeff N.]

I see them fail mostly at the inlet weld to the aft muffler. Rot. Not sure what you can do to fix that.

A more interesting project might be figuring out to modify the stock muffler tone. I recall the Dinan setup basically being a stock Eberspracher unit that has been opened up, baffles modified, then welded shut again. Oh yeah, that and some fancy tips being added too.

Jeff

[Dash01]

Well, my old resonator looks pretty good, and probably still has some life in it.

The rear muffler actually looks pretty good too, but has some rust and a hole or two in its outer shell. It appears to have a double lining, with the visible part of the inner shell not bad looking. The guts must be shot: Although pretty quiet at cruise speed, the car has/had a low frequency rumble that carries for a distance when idling.

So, before I toss out the old muffler, I'm wondering if it might be worthwhile to cut it open and repair/replace whatever seems missing or shot on the inside. Could do this pretty cheaply via the high school metals shop, where teacher knows local sources of perforated stainless steel, tubing, rockwool packing, etc..

Granted, it's a lot easier just to put on a new OEM muffler from BMA, but even those are still pretty pricey: This might be a way to save a few hundred bucks, learn new skills, recycle, and have a muffler guraranteed to fit.

Suggestions welcome.

PS: If anybody has ever wrapped rear aftermarket muffler and/or pipes with exhaust wrap, here's a question: Did the exhaust wrap make the muffler/pipes any quieter, by dampening vibration of the metal?




QUOTE=Jeff N.]I see them fail mostly at the inlet weld to the aft muffler. Rot. Not sure what you can do to fix that.

A more interesting project might be figuring out to modify the stock muffler tone. I recall the Dinan setup basically being a stock Eberspracher unit that has been opened up, baffles modified, then welded shut again. Oh yeah, that and some fancy tips being added too.

Jeff[/QUOTE]