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Old 01-07-2014, 02:12 PM   #21
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Quote:
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I posted most of them in the fab thread I think.
I looked for your aluminum exhaust info in your SSM build thread but didn't find it. Did I miss it, or do you have another thread?
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Old 01-07-2014, 02:14 PM   #22
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Quote:
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I looked for your aluminum exhaust info in your SSM build thread but didn't find it. Did I miss it, or do you have another thread?
Its in the fab thread not my build thread since its not on my car.
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Old 01-07-2014, 03:02 PM   #23
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Quote:
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Its in the fab thread not my build thread since its not on my car.
went through fab thread and this is all there was.


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Just made a couple exhaust hangers for a buddy, he wanted them to clamp on. I heated up the 304 rod with the oxy acetylene torch and hammered it flat on the anvil. We happened to have some 2.5" Al round stock in short sections kicking around so I hammered the bend into it around that.





And then today and I used all of this.



And you know, just made some custom mufflers... out of aluminum.



Yup, made those cores out of perf sheet did that a couple weeks ago.






So remember how I complain about the Dynasty we have. Yeah I'm never going to use pure tungesten in that thing again. All those welds were done with thoriated, 1/16" with a #6 cup. 120Hz, some were done at the balance of 45% that I was using to try to make the pure tungsten work, the rest were done with 60%. And zero weld prep, we didn't have a clean stainless brush in the shop so I figured using the welder to break through the AlOx was better than getting steel all up in the weld. We were also out of acetone.













no exhaust pics, just mufflers. do you know the lengths/diameter of the mufflers you made?
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Race exhaust-img_20130427_183915.jpg   Race exhaust-img_20130427_183919.jpg  
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Old 01-07-2014, 03:12 PM   #24
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Oh I didnt put in the "finished" pics. Heres the only under car shot.





Note that 2nd shot is in no way how it goes together. Its got a couple different configurations and I ran out of spare v-bands so its kind of just stuck together randomly so I could weld the vbands without warping them. The most difficult part of this is getting the header flange in 6061, you got to make it yourself I used a cnc, it could be done with a hand drill and hack saw though.
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Old 01-07-2014, 03:52 PM   #25
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I wonder how you're getting away with aluminum perf when Emilio says he's burning out 304 stainless? I thought stainless had a way higher melting point. AutoX vs track I guess?
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Old 01-07-2014, 03:57 PM   #26
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I wonder how you're getting away with aluminum perf when Emilio says he's burning out 304 stainless? I thought stainless had a way higher melting point. AutoX vs track I guess?
And also e85. And the midpipe muffler was definitely having heat problems. Though the two times it melted were the two times it was on the dyno.
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Old 01-07-2014, 04:13 PM   #27
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the aluminum mufflers I have seen (online) being built have used stainless perforated tube with aluminum end caps, weld stubs and case.
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Old 01-07-2014, 04:14 PM   #28
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Maybe that would have been a better idea. Then at least I could have gotten the perf cores pre-made rather than having to roll my own.
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Old 01-07-2014, 04:33 PM   #29
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Just got off the phone with tech support at FlowMaster. Was looking for design info on the Hushpower and learned some interesting stuff.

The HP-2 has been redesigned and is now available in a more compact case with the same internal size. The case ears are now gone. And a longer one is available so you can get 12" and 18" case lengths in 2.5". Don't know about the larger pipes you guys use.

The HP is not a chambered muffler. It has two perf cones which meet in the center of the can at the cone bottoms. So the flow goes in the cone, passes into the can, and back into the second cone. They claim no pressure loss compared to open pipe on a flow bench.

And they have a larger version of the same technology available called a DBX. His suggestion was to run a DBX or an 18" HP in the rear location and then after trying it, add a 12" or 18" HP mid-pipe if more silencing is required. Quoting him, with this technology you could make up an entire exhaust system with HP's connected end to end over the entire length of the car and it would still flow like an open pipe. He said it, not me.

Part No's: 12512409, 12518409, 12514310
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Old 01-07-2014, 07:50 PM   #30
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I thought that using the same mufflers back to back wouldn't help with sound anymore than with just one. Mainly because they have the same tone or something along those lines. But hey, I could be wrong and/or that's not what you meant..
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Old 01-07-2014, 08:15 PM   #31
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I thought that using the same mufflers back to back wouldn't help with sound anymore than with just one. Mainly because they have the same tone or something along those lines. But hey, I could be wrong and/or that's not what you meant..
Kind of, when dealing with an absorptive muffler, IE a glass pack, having the same muffler back to back doesnt do much more than just the single muffler. Thats why my racecar has both available lengths of the dynomaxx bullets in 3" mounted end to end in my midpipe.
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Old 01-07-2014, 08:32 PM   #32
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Quote:
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Kind of, when dealing with an absorptive muffler, IE a glass pack, having the same muffler back to back doesnt do much more than just the single muffler. Thats why my racecar has both available lengths of the dynomaxx bullets in 3" mounted end to end in my midpipe.
Makes sense, never saw the dynomaxx before.. Seem pretty affordable.. I guess you like them?
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Old 01-07-2014, 08:38 PM   #33
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They're ok. Lightish and cheap and cut down the noise. 409 stainless is the downside so they will rust.
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Old 01-07-2014, 09:27 PM   #34
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You know, I questioned him about the two muffler thing too. He said what we're talking about is true of tuned cavity-style mufflers but not linear mufflers. As an example, you wouldn't expect a 20" glasspack to be no better than a 10" glasspack. Longer is better, and building length in "modules" is okay.

Previous HP's could be had in 409 or 304SS for a few bucks more. Don't know if that's still true. But the website says all stainless steel has a lifetime warranty.

My bigger concern would be not knowing if a muffler that free-flowing is up to silencing a supercharged engine. I've got a supposedly pretty good street/race muffler on a supercharged rally Rabbit and it's a serious ear-bleeder.
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Old 01-07-2014, 09:41 PM   #35
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Muffler packing volume is the real secret to reducing noise. You see those mufflers I made that are super quiet? They've got more volume than the monster magnaflow and the whole system weighs less than it. If its too loud just keep jamming more and more mufflers with more and more packing volume under the car until its quiet enough. Most of the weight of the muffler is in the case.
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Old 01-07-2014, 09:47 PM   #36
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Muffler packing volume is the real secret to reducing noise.
I believe that. I've never seen a micro muffler with serious capability.

I wonder why no one produces anything similar to yours? You'd think there would be at least a small enthusiast's market. Maybe that's your ticket to joining the 1%.
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Old 01-07-2014, 09:50 PM   #37
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Ha, those things take like 4-5 hours a piece to make, would take an hour less if I could find pre-made perf cores. If I wanted to make real money they'd be on the burns stainless cost level. Though on noise attenuation/weight ratio they kill Burns.
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Old 11-11-2017, 11:42 AM   #38
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Dragging this one back up because the thread is on point for my question. What did you DIY muffler guys use for packing? The muffler specific stuff is stupid expensive and I can only find it for dirt bike mufflers. Any concerns with using mineral wool insulation cut to size? Maybe break it up and pack the muffler that way? Just looking for packing material that won't cost more than a premade muffler.
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Old 11-11-2017, 11:56 AM   #39
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A good material I have used is Ceramic Wool (kaewool?). My exhaust has been using it for a couple of years without losing the packing (I added a semi-fine stainless mesh outside the perforated core to ensure it wont just peel and escape).
Its not too expensive, no heat issues ever (you wont be able to melt it with a TIG torch even). As for weight, id say its just as heavy as rock wool.
As usual with fibers, its quite nasty, even nastier than fiberglass. Breathing protection mandatory, tight suit and gloves recommended.

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Old 11-11-2017, 12:10 PM   #40
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spec-31
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