Stainless steel wool for exhaust packing


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roadwanderer2
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Motorcycle: previously owned 83 GL1100A aspencade traded for a motorhome, 1981 honda GL500i silverwing interstate, 1974 yamaha xs400, 1974 Honda cb450 twin cam, 1983 honda vt30, 1982 honda 700 shadow, 1972 cb750four, and my first bike, a brand new 1982 honda CM400e. now own-1986 GL1200 aspencade SEi
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Re: Stainless steel wool for exhaust packing

Post by roadwanderer2 » Mon Apr 27, 2015 7:48 pm



Hey FM, that's a nice mockup you made there. im gonna have to give that a lot of thought. it looks very doable.

stuart.



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DJnRF
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Re: Stainless steel wool for exhaust packing

Post by DJnRF » Mon Apr 27, 2015 7:53 pm

FM-USA wrote:JUST
. . . doodling . . .

Wool-Pack-Muffler.PNG

That is some doodling! What size washers did you use, and did you have to
drill out the center hole any? What size is the center hole?

I would need to cut my tail pipe turndown, but that looks doable.
With the turndown off, I could remove the packing I had put in,
and redo the whole thing. Does the back pressure increase much?
With my older 1100 engine, I don't want it to increase more than
the 1 or 2 pounds more than the 1 pound factory back pressure.

That system isn't as complex as a good firearm silencer, but it
is getting closer.

Dave.
"Survival is one's own ability to cope with and overcome any adverse or threatening situation, condition, casualty or event." ©Dj 1969

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Re: Stainless steel wool for exhaust packing

Post by FM-USA » Mon Apr 27, 2015 8:12 pm

OH, I never made that, just a doodle, but it sure looks good.
It was a quick thought mixing 'Cherry Bomb' muffler, wool packing and gun silencer air spaces.


Fender washers, whatever fits near tightest and some space for wool for anti-rattle.
I'm sure a 3/8 or 1/2 inch fender washer will be real close.

I would need to cut my tail pipe turndown,
HANG ON!!!!
Let me do some Real Doodling tomorrow with this other idea I have.
Might not need any bolts or washers at all. :idea:


.
"Tact is the ability to tell someone to go to hell in such a way that they look forward to the trip." W.C.

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roadwanderer2
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Re: Stainless steel wool for exhaust packing

Post by roadwanderer2 » Mon Apr 27, 2015 9:00 pm

i think it looks pretty good. cant wait to see what GM comes up with tomorrow lol.

niters yawl.

stuart.

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DJnRF
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Re: Stainless steel wool for exhaust packing

Post by DJnRF » Tue Apr 28, 2015 12:39 am

[/attachment]


FM-USA wrote:OH, I never made that, just a doodle, but it sure looks good.
It was a quick thought mixing 'Cherry Bomb' muffler, wool packing and gun silencer air spaces.


Fender washers, whatever fits near tightest and some space for wool for anti-rattle.
I'm sure a 3/8 or 1/2 inch fender washer will be real close.

I would need to cut my tail pipe turndown,
HANG ON!!!!
Let me do some Real Doodling tomorrow with this other idea I have.
Might not need any bolts or washers at all. :idea:


.

Great! I always love to hear ideas. In the meantime, I have attached a diagram
of a Type 7 reactive muffler. It says that it isn't showing any baffles. Mentioned
is one or two. From some of my muffler books, and info from a couple of
companies, this type of muffler can be expensive as it is made with the very
best of materials, and all stainless steel. I can't find the name of the material
that is used most for sound suppression, but it isn't merely fiberglass.

Now, this type of design using several to many baffles is what makes the
best type of firearm silencer. A muffler must do the same type of job. The
one thing that makes a difference between the two is that firearms are
designed to handle the back pressure that might be caused by a silencer,
and internal combustion engines are not so designed, and can be affected.

The natural back pressure on the Type 7 muffler is listed as 1 psi.

Will check back again tomorrow.

Dave.
"Survival is one's own ability to cope with and overcome any adverse or threatening situation, condition, casualty or event." ©Dj 1969

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Re: Stainless steel wool for exhaust packing

Post by FM-USA » Tue Apr 28, 2015 4:52 am

DJnRF wrote:


Great! I always love to hear ideas. In the meantime, I have attached a diagram
of a Type 7 reactive muffler. .. The natural back pressure on the Type 7 muffler is listed as 1 psi.
Will check back again tomorrow.
Dave.
That 'Type 7' has all the earmarks of a 'Cherry Bomb' muffler. The differences are...
* The oval shape helps offsets impulses to reflect into one another at different intervals.
* The packing material is not around the baffles pressure relief holes. It's safely tucked to the front absorbing some of the impulses while the other empty end reflects impulses back hence partly canceling out said impulses. Notice in this design there are 2 different densities of packing? Different frequency and pulse absorptions, both direct and redirected from the opposite end. Theirs a whole lot going on inside a muffler that many don't directly see.

Impulses are more than just air pressure pulses, they're also sound frequencies.


It's always amazing that a straight through design like Type 7 is has any back pressure at all. But what pressures goes into the outer chamber will reflect back into the inner tube and that will slow down the next pressure wave(s).

For those who have acute hearing. Ever notice in some mornings your car sounds a little quieter than when it's well warmed up? There's moisture inside the muffler, and if you have one, the resonator. Moisture in the air helps deaden or slow down pulses and sound frequencies until it's evaporated away.
:geek:
"Tact is the ability to tell someone to go to hell in such a way that they look forward to the trip." W.C.

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DJnRF
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And, many others since I started riding. Started on a Harley in 1956.

Re: Stainless steel wool for exhaust packing

Post by DJnRF » Tue Apr 28, 2015 9:55 am

FM-USA wrote:
DJnRF wrote:
Reactive Muffler.jpg
Great! I always love to hear ideas. In the meantime, I have attached a diagram
of a Type 7 reactive muffler. .. The natural back pressure on the Type 7 muffler is listed as 1 psi.
Will check back again tomorrow.
Dave.
That 'Type 7' has all the earmarks of a 'Cherry Bomb' muffler. The differences are...
* The oval shape helps offsets impulses to reflect into one another at different intervals.
* The packing material is not around the baffles pressure relief holes. It's safely tucked to the front absorbing some of the impulses while the other empty end reflects impulses back hence partly canceling out said impulses. Notice in this design there are 2 different densities of packing? Different frequency and pulse absorptions, both direct and redirected from the opposite end. Theirs a whole lot going on inside a muffler that many don't directly see.

Impulses are more than just air pressure pulses, they're also sound frequencies.


It's always amazing that a straight through design like Type 7 is has any back pressure at all. But what pressures goes into the outer chamber will reflect back into the inner tube and that will slow down the next pressure wave(s).

For those who have acute hearing. Ever notice in some mornings your car sounds a little quieter than when it's well warmed up? There's moisture inside the muffler, and if you have one, the resonator. Moisture in the air helps deaden or slow down pulses and sound frequencies until it's evaporated away.
:geek:



Ahhhh, you do understand the complexities of mufflers. A couple of things here, though.
The Cherry Bomb muffler is a type 20. The difference between it and the type 7 is in,
first - the shape (round vs oval); second - one typical fiberglass packing is wrapped
around the through tube, and nothing else.

In the type 7 the packing does completely wrap the core tube, but has the mesh
wrap around it before the type of packing used, which is not fiberglass. Baffles are
still mounted onto the core, but evidently only one was used in this diagram and
is not seen due to the incomplete covering cutaway. The packing shown, just like
the mesh, was not completed down the length of the core tube merely for the
diagram to show the basic construction.

Most don't understand that all sound waves cause pressure, and that the pulses
are sound waves that have caused them.

Motorcycles have a very similar construction to the type 7, OR the type 20. Due to
physical size constraints they can't be as large, or use much of any oval shape.
To the user, the quality of one over the other is part of the huge price differences
that can be found on motorcycle exhaust systems. Of course, corporate greed can
have an impact on some poor systems being priced close to good ones. That is
why it is usually better to purchase systems actually made by the manufacturer
of the machine. It can be a real hassle for the average person to research a
product enough to know what they would get.

Over the years in business I have had many communications, and talking with
several manufacturers. I was amazed at their experimental research of many
different systems. Some very high technology is used in development of the
types of systems for different types of vehicles. I have amassed several
boxes of books just on these systems. I didn't realize how many until I just
had to pack and move them all to my new home. That is also how I found
this diagram I had gotten a number of years ago. Papers/ books on theory,
testing, and the like are all packed in six boxes here. I just don't have the
time to read them all again. lol

TC,

Dave.
"Survival is one's own ability to cope with and overcome any adverse or threatening situation, condition, casualty or event." ©Dj 1969

FM-USA
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Re: Stainless steel wool for exhaust packing

Post by FM-USA » Tue Apr 28, 2015 10:05 am

OK, testing done... didn't work, no real lowering of decibels.
I tried alternating two sets of dense pad and a washing machine lint trap.

I also tried opening the (nearest to motor) pad to be looser than the second with the lint trap in between.

I also used a piece of cardboard and fit around the tailpipe to shield some of the bikes general noise and muffler. So in my case, one pad works as well as two pads.

OH-well. Now we know... at least me :)
"Tact is the ability to tell someone to go to hell in such a way that they look forward to the trip." W.C.

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Re: Stainless steel wool for exhaust packing

Post by FM-USA » Tue Apr 28, 2015 10:14 am

DJnRF wrote:Ahhhh, you do understand the complexities of mufflers.
Dave.
Ya, I toyed with pipes in my past.... no exhaust pipes.
OK-ok, those too. LOL!
:mrgreen:

After seeing the cutaway of the GL1500 muffler, Honda has a good handle on reflected sound cancellations.

.
"Tact is the ability to tell someone to go to hell in such a way that they look forward to the trip." W.C.

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roadwanderer2
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Re: Stainless steel wool for exhaust packing

Post by roadwanderer2 » Tue Apr 28, 2015 11:45 am

did you also know that the round "cherry bomb" glass pack muffler has directional baffles inside? pictured below are 2 views of your "typical" round cherry bomb muffler. notice the baffles, if this muffler is installed with the baffles facing front, the sound will be quieter, facing rearward it will sound louder.

stuart.
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DJnRF
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Joined: Fri Oct 04, 2013 8:50 pm
Location: FINALLY! Moved to a new home in Creve Coeur, IL.
Motorcycle: 1981 GL1100i Interstate
And, many others since I started riding. Started on a Harley in 1956.

Re: Stainless steel wool for exhaust packing

Post by DJnRF » Tue Apr 28, 2015 8:27 pm

The old Cherry Bomb mufflers had a nice sound to them. Back in the 50's
they were very popular. It drove the police nuts back in those days.

Personally, I have always liked a very quiet vehicle better. One exception
was my Hog. I loved to hear the pistons when I retarded the timing. I
would drive downtown and at stop lights between the tall buildings I
would retard the timing just to hear, first one piston, then the other;
'kathump - kathump', 'kathump - kathump'. That sound was heavenly,
and especially so since the exhaust was not very loud on that machine.

Dave.
"Survival is one's own ability to cope with and overcome any adverse or threatening situation, condition, casualty or event." ©Dj 1969

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lovat
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Re: Stainless steel wool for exhaust packing

Post by lovat » Wed Jun 14, 2017 1:42 pm

Hey Everyone,
I thought I should report that I packed my exhaust on my '86 Interstate (GL1200).

Regarding the image below:
The first little section is my friends 1500(just the right side), then my 1200 (right, then left), reading the highs there at 105db or so.
then the last two sections, with that little dip inbetween (right then left), showing about 88db.

This is an approximate 17db drop from 1/2 of a pad in each side.
It's now so quiet, that all I really hear is the engine.

This will be good, because I'm volunteering at a marathon this weekend, and will be on the course next to the runners.





Not quite as quiet as my frinds 15oo, but I'm happy with this.


'86 GL1200 Interstate
Northern Minnesota
KD0UYN

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