Muffler material question.

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The Artist formerly known as Turbo84
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Clinging to my guns and religion in KCMO.
I'm kicking around welding up a muffler for the '69. It looks like one bigass custom muffler would be lighter than the two I presently have, and I can place the weight where I want it to be. I'm still designing the layout of it, but I'm pretty sure I'm going to want to put some fiberglass strand in some chambers to dampen some frequencies. My question is if there's anything unique about the fiberglass in glasspacks, or if it's basically the same stuff as attic insulation.

thanks,
Mike
 
I bought some stainless steel wool "on a roll" that I found on Ebay... it was quiet expensive at $70 but should last a long time - I guess I'll find out whenever I finish the mufflers I was going to build back in 2009....LOL....

IMO, fiberglass will burn eventually. If you're lucky it will survive welding the muffler, from then on it's downhill.... any muffler insulation (fiberglass or steel (stainless) wool) will trap moisture - probably one reason why the Flowmasters seem to last forever....
 
I bought some stainless steel wool "on a roll" that I found on Ebay... it was quiet expensive at $70 but should last a long time - I guess I'll find out whenever I finish the mufflers I was going to build back in 2009....LOL....

IMO, fiberglass will burn eventually. If you're lucky it will survive welding the muffler, from then on it's downhill.... any muffler insulation (fiberglass or steel (stainless) wool) will trap moisture - probably one reason why the Flowmasters seem to last forever....

I've got a bunch of SS wool left over that I used to quiet down my shorty pipes on my Triumph, and I was going to use this stuff to try to knock down other frequencies and also allow a bit of gas flow between chambers.

The physical construction of the muffler will somewhat mimic a Flowmaster as I'm going to have to weld everything, versus crimping the ends like on the present mufflers.
 
I built the sidepipe mufflers for my brothers car. It's stainless perforated pipe w stainless wool that I tightened down w/ stainless wire locking wire (pulled tight by wire locking). Packed them tight. They sound awesome. An absorption style muffler is easy to build, a cancellation style not, get the chambers wrong and it will sound terrible. Generally absorption mufflers flow better too. You can always buy a stainless magnaflow one. if you really want super light and are not afraid to spend mucho dinero, look at burns stainless.
 
I built the sidepipe mufflers for my brothers car. It's stainless perforated pipe w stainless wool that I tightened down w/ stainless wire locking wire (pulled tight by wire locking). Packed them tight. They sound awesome. An absorption style muffler is easy to build, a cancellation style not, get the chambers wrong and it will sound terrible. Generally absorption mufflers flow better too. You can always buy a stainless magnaflow one. if you really want super light and are not afraid to spend mucho dinero, look at burns stainless.

This muffler is going to be primarily an absorption style, but with chambers/plenums to act as accumulators/"capacitors"/buffers to convert the exhaust pulse flow into quasi-steady flow. I don't have time to do multiple samples while experimenting with cancellation methods, although an adjustable internal chamber volume (moving one of the walls externally via a long bolt or all-thread) sounds interesting. It should be easier to quiet things down if I can clip the peak exit flow rate by adding chamber volume rather than adding restriction to the system.
 
I've got a few ideas drawn up for the muffler. I'm contemplating initially having a removable cover on one side so that I can make internal changes to the thing in case I don't like the noise level/quality or backpressure level. With this, I'll probably need to track down some sort of high temp gasket material in thin sheet form so I can cut it to shape. Any suggestions for material or sources?

thanks,
Mike
 
or simply have the cover to muffler body flange wide enough to use a simple bead of red hi temp silicone. It really works well. I've used it on collectors and what not.
 
or simply have the cover to muffler body flange wide enough to use a simple bead of red hi temp silicone. It really works well. I've used it on collectors and what not.

Gotta ask the obvious....what ARE the typical dual with X or even H pipe on a ~350 ci engine at 6000 rpm?? pressures, speeds/

and I suppose that all depends on where you measure in the pipe....header to muffler....

I look at it a helmholtz resonator.....like 'bass reflex' speaker systems I used to design and build.....decades ago....

but know that a muffler makes it act like a 'acousic suspension' system....

:drink:
 
I've got a few ideas drawn up for the muffler. I'm contemplating initially having a removable cover on one side so that I can make internal changes to the thing in case I don't like the noise level/quality or backpressure level. With this, I'll probably need to track down some sort of high temp gasket material in thin sheet form so I can cut it to shape. Any suggestions for material or sources?

thanks,
Mike

You could use the high temp rope seal they use for seal packing in valves.
 
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