DIY Generator Muffler Build (Version 2.0) - The Trashcan Muffler - Bride of Franken-Muffler
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- Опубліковано 5 лют 2025
- For those of you that tuned into my very popular DIY Quiet Generator Shed Build video, or the follow-up video about how I built the infamous trashcan "Franken-Muffler", here is a video answering many of the Frequently Asked Questions about those projects. This video contains some of the upgrades the I did to the exhaust system to make it more efficient, as well as a parts list that I used, and a few other tidbits of info about the project. So, if you have an interest in Quiet Generator Sheds or Generator Mufflers, here is your video. If you haven't seen the previous videos, check them out at the links below:
DIY Quiet Generator Shed Project video (Shed tour with sound tests):
• DIY Generator Shed Bui...
The FrankenMuffler Lives! DIY Trashcan muffler - Version 1.0:
• DIY Generator Muffler ...
In Australia, in the 60's we built a series of 3 large powerful tractors using army tank and war surplus parts with various engines. A diesel Detroit V8 was in one. A clever fellow who worked for me at the time, designed and built very large but very quiet mufflers for all 3 tractors, 2 mufflers for the V8, out of 44 imp. gallon fuel drums.
The mufflers stood upright, bolted to the chassis inlet and outlet at the top. Vertically it was divided into 2 halves by a big sheet internally with an 8'' hole at the base for the gas between chambers. Then there were 10 baffles welded horizontally, with gas holes.The twin exhaust stacks were 6 pounder cannon shell canisters about 10'' in diameter. It produced a deep but quiet and beautiful V8 sound.
That sounds awesome! And also, completely bad ass. I don't think you can beat cannon shells for coolness. Although, most people wouldn't consider cannon shells as sound deadening devices. Well done to the bloke that came up with the idea.
Yes, it was long, but MAN, did you cover every question (+ dumb ones) and with excellent photos!! Thanks for your excellent research. A five star presentation...you really set the bar for all other UA-cam "how to" presenters!
Thanks for the kind words! I'm pretty new to this UA-cam content thing. But I just tried to create a video that would answer all the questions that I myself would ask and would appreciate someone else presenting. Sometimes the design process is as interesting as the end product. Who would have thought that building a little shed would lead to a bunch of videos?
Great work. Really well done. A few suggestions:
1. Add another fan for the intake instead of the material.
2. Adjust the exhaust fan so that it's at the highest possible point in the shed. Heat rises, and quickly.
3. Don't put your propane tank in the shed with the generator. If the fan fails, or if you have an extremely hot day and the tank is near full, the LP in the propane tank will start to expand quickly. If it expands too quickly, the tank will start to blow off propane through the pressure release valve and fill the shed. Propane needs the proper air mixture to explode, but I wouldn't risk it. Buy a 10 or 20 foot hose and put your tanks well away from the ignition and heat sources.
Well said
Very informative and great details. Thank you. P.S.- ignore the critics for pointing out their insecurities. I like your ingenuity in using what your have, example of the helmet cam, genius idea. You are obviously very intiitive.
I appreciate that!
I did build a generator shed from some ideas out of your shed generator original video… after watching this video, I will install a wider diameter exhaust pipe like the one you have on this last video.
Thanks very much for sharing!!! 👍👍
I really like the slides with bullet points to go along with your explanation. Well done.
Thanks. I took the opportunity to use some of the advanced PowerPoint features that let you turn presentations into videos. All of the features are available in Powerpoint to do the voiceovers, record the mouse, and publish as a video. I think it worked pretty well, and was pretty easy to use.
Extremely well presented. Thank you for the information. A master class well taught!
I followed your steps to the T and I'm super happy with the results! If anyone is considering doing this let me say it works perfectly. It definitely takes time and patience but the results are awesome. One thing I'd recommend is I used a 31 gallon trash can and ratchet strapped the lid down got rid of the extra vibration. Also I added some feet with vibration absorbing pads and it helped as well. I can literally have a conversation right next to the shed with the generator running no problem. Thank you so much for sharing your wisdom.
Great to hear that it worked well for you. These were just ideas that I decided to share that anyone could apply to their own generator sheds, since this whole thing was essentially just an experiment on my part. I detailed my recipe, but the best thing is that you can use the ideas and approaches with whatever you might have at hand and probably achieve similar results. And, as you found, you can add your own tweaks and make it even better.
I am at this point. I have my shed built and all I have left is this. I considered using large Stove pipe with caps on the ends instead of a metal trash can because you can attach the stove pipe to the shed since they do sell wall attachments for stove pipe. The issue there is you can get large stove pipe but it would never be as big as what you are using. This is going to take a bit of thought and research. Your Exhaust system is the key to all of this and I thank you for it.
Sounds like an interesting approach. As I said in the Version 1.0 video, the trashcan was just a convenient object to pack a bunch of insulation into and scale-up a glass-pack muffler concept. Almost anything can work. It doesn't even have to be round. Just some container that can absorb some of the sound, and preferably won't catch fire in the process. Glad you are taking some of the ideas and running with them. That was the entire point of the video, thinking outside of the box and applying some of the principles to make these generators quieter, no matter what materials you might have laying around. Good luck!
Great creative garage engineering and thank you for making the (significant!) effort organizing, documenting and presenting. Hope neighbors enjoyed your walking around for hours with helmet on. Thank you!
Thanks for watching. The neighbors don't even know what I look like, since I ONLY wear a helmet outdoors. You can never be too careful. Plus, it's for their own protection.
Very informative and detailed. Thank you. I have been putting the list together to proceed with this, and I had a few questions for you or this group.
1) Internal ventilation of shed; My proposed approach would be to use an attic fan, but place it on the lid, with a roof/rain cap (GAF Masterflow ~1250CFM). Heat rises, sure, but with forced air does not matter. The benefit is that the opening would be on the top side and not direct the noise up and not to side, maybe not requiring the baffle box on exit. Had you considered that or reason to have gone with exhaust to side?
2) Direction of exhaust, if the concern is the noise out the pipe, did you consider going straight up after the side of the shed. A small rain cap on top of 2" EMT or even the 3" double wall like a gas water heater all the way up. I would consider the vertical placement of the pipe 1-2 feet above head levels would remove it from people head. My proposed would be to direct it all the way up to 2 feet above eve roof line (12 feet total height). I have been trying to find other installations with a vertical stack but unable to.
The video is fantastic, and I appreciate your detail and approach to explanation.
I didn't put the fan on the top of the shed for a couple of reasons. 1) The fan is heavy and the plastic lid of the shed would have bent down. It also would not have allowed the lid to stay open with only the stock gas struts that came with the shed. 2) Rain. The shed needed to be weather proof. While the attic fan does have self-closing slats that close when the fan isn't running, it wasn't water-proof. There are other fans that do have a rain cap, but they are even heavier. If you are going with a sturdier shed, then you can certainly go with the roof mounted fan approach.
Pointing the exhaust pipe up at the sky or down at (or under) the ground is definitely an option. You do need to think about rain intrusion. The method I used is just one option among many.
Thank you for all the details:)
I was also inspired to build a copy for my camper generator since I has almost all parts laying around. Since had to be portable I made it from a section of 8 inch galv duct, two endcaps, rockwool, and some 1/4 galv mesh wire. All I had to buy was the 1 in flex pipe. Basically a glass pack EXCEPT I placed four 4 1/2 dia. abrasive cutoff disks (heatproof) spaced down the middle inside the wire mesh tube to act like a gun silencer construction. Packed the rockwool around inner wire mesh tube. This seems to work very well. Thanks for the inspiration.
4 words, awesome, thank you...subbed!
Sorry for premature comment I see you have the fiberglass tape coming. You spent a ton of time on this and it's very detail oriented. Great Job! I had no idea dirt bikes of that size could be battery powered.
Yeah, love these bikes. They are so fun! Look up "Alta Redshift" on UA-cam. Lots of great vids. They aren't silent, but they are much quieter than an internal combustion bike, so you can ride them places you wouldn't normally be able to ride. They pretty much outclass most dirt bikes except for range and recharge time. Hopefully that can be addressed in the coming years as battery tech advances.
If you really want to see what an electric dirt bike is capable of, besides the Alta Redshift you can look up the newly announced Stark Varg. It looks seriously impressive (think 80hp, 6 hour runtime, lots of really innovative features.)
Very nice job reengineering the the Franken - Muffer System.
Thank you for listing the parts needed for fabrication.
I really like the increase in the diameter of the outlet pipe as it exits the engine.
I am in the middle of my build. The problem is that the rockwool board is not available near me right now and shipping currently exceeds the price of rhe board!
My generator is only a 120v 4500 watt Champion, and Im planning ro put some kind of muffler inside the shed and vent the exhaust outside.
Thanks for showing us you parts for the exhaust pipe. Enlarging that pipe is crucial
What a great idea.
Great project, I might copy it.
I use similar rubbih bins to store bird seed and keep out the squirrels. I use over centre catches to hold down the lid and that works really well. There are screw adjusting catches available so you can fine tune it. They don't perish in the sunshine as bungies do. How about a ring seal, maybe rubber, maybe rockwool if you can keep it contained to stop lid leakage and rattling.
Those look like great ideas. Will have to look into the catches you mentioned.
Just stumbled on video. Excellently done.
Life saver! I really have a problem with this before. Thank you so much!
I built a wooden sound reduction shed with a hinged roof. I used many of your ideas, thanks. Now I need to fully figure out the exhaust system and get the right gas lifting arms for the roof weight. I want add a 50 amp plug behind the meter that senses power when it is on/off. Thanks again for sharing your ideas, well done and very good information.
Your timing is perfect. I was just about ready to start on my own build based on your original videos. Thank you for this update.
Great video, great presentation, organized and precise and immensely informative thank for taking the time out to do this! you sir get AAA+++ rating.
Just wanted to thank you for continuing to share your improvements. I just retrofitted my Craftsman horizontal shed this weekend and used many of your ideas and learnings. I watched a ton of generator enclosure vids the last few weeks before finalizing my plans and your parts list & logic for your build was invaluable, thank you. I am using a Zombie box muffler that I ordered, but am still considering building my own Frankenmuffler 2.5. Good stuff!
Sounds awesome. Would love to see the final result! Good luck.
I just ordered a Zombie Box muffler for mine. How's yours treating you?
will continue watching this new upload. I think some hardy cement board on the outside and inside would help where the pipe passes through. I can tell you even with the extra pipe you have that walker exhaust is going to get 600 degrees and that's a point where my shed started to melt even though it was incased in a 4 inch dryer vent. In retrospect I saw a video where the builder cut a 6 inch hole in the shed but a 4 inch hole in two pieces of hardy or in your case a 4 inch in the shed and 2 inch in the hardy. I also wrapped the walker exhaust with muffler fiberglass tape and that has seemed to help. I was getting temps up to 130 in Houston.
For very budget-conscious people wanting to build a generator quiet box, I used an IBC tote, removed from its cage, lined with insulation material. Cut one door in the front, trying to retain as much structural support as possible as the tank is not completely rigid once cut. The top cap hole or the bottom tap hole can be used for exhaust venting. Tank is mounted on a strong wooden pallet. You could add wheels to move it around etc
👏 Thank you for such a thorough explanation! Nice work
8:05 Cut up some rock wool into small pieces and pack them into that into the 3 inch vent that you are running the exhaust pipe through. This will not only protect the plastic even further from heat, but also prevent insects from traveling through the larger opening. Nothing like opening your enclosure to find a beehive. I might also want to have the exhaust pipe entering the trash can towards the bottom of the can, and have it exhaust somehow towards the top, as hot air rises, which would aid in keeping things as cool as possible. The biggest challenge here is finding a way to exhaust without letting rain or snow in.
I actually did pack some rockwool into that 3" vent, around the 2" pipe. You can see a piece of it hanging out in the main cover pic, and at the intro to the video if you look close. Not super practical if you take the 2" pipe in and out though. When not in use, I put the garbage can in the shed, and I put a cap on the 3" pipe. And yes, the exhaust goes out the bottom on this design to keep the rain out and also to make the sound turn one more corner at the bottom to dissipate a little more energy.
thanks for your video..just did my box with same generator and looking to sort out exhaust routing, was interested on how you tapped the exhaust. glad I stayed to the end to see how you created shaped chamber in the garbage can....good ideas
In the version 2.0 exhaust that I covered in this video, I just had a small piece of 1" threaded pipe welded to the tip of the muffler outlet. In the earlier (version 1.0) exhaust, I used a 3/4" (pipe thread) tap to tap the inside of the exhaust outlet. As I explained in this video, though, I don't know if I would recommend that method, because it does drop the inside diameter of the pipe down to 3/4".
I apologize if I missed this, but it seems like there are two potentially simple refinements to this approach which wouldn't require much heavy rework: 1) coating the walls of the muffler with acoustic material (e.g., dynamat or roof flashing) to reduce transference 2) Putting the metal muffler can within another vessel such as a 55 g drum or rubber trashcan, potentially lined with absorbent material.
You can certainly keep adding layers to the whole thing ad infinitum. Layers on layers, sound walls, redirection of sound upward or underground, sheds within sheds, etc. The sky is the limit. But then apply the law of diminishing returns, and you'll eventually have to draw the line somewhere. Those were all good suggestions, and if you have the time, space and resources, you can keep adding mitigations. Or just buy a quieter generator. Thanks for the ideas, which is what these videos were all about.
Great build!
Thank you very much for all your work.
Have you tried clocking the layers back and forth? I'd think as long as you leave the same sixa passthrough as the factory muffler, it would flow well and have that many more turns to deaden the sound! All the pieces are cut, so trying that would simply take a few minutes and really nothing more. Something else I was thinking about is putting your sound diversion boxes on the inside of the shed. It would make for a better package and keep everything out of the rain. Also, maybe add a horizontal piece of the insulboard to the inside to make the air turn yer again..... I would also love to know how long it takes to get the temp of the outside of the muffler to "TOO HOT TO TOUCH" levels?? I think this is a great project and with us going through a hurricame here in Northern Tampa Bay right now, this is definatelly on my mind..... Thanks for sharing......
I came from your 1st Gen Video. Amazing Video and Explanation. Thanks for sharing your design, ideas, and explanation!!! Love the improvements and thought put into your 2nd Gen, and thanks for the feedback on my previous videos comment!
In the previous video I commented about potentially using 3-5" river rock with Rockwool lining. To elaborate I was simply trying to think of ways to use more volume of the can by potentially using diffusion. The main idea would be to use more surface area of the Rockwool to absorb the sound by diverting it. I think having the Rockwool right up against the screen reduces the surface area and the rest of the Rockwool probably isn't being very effective with the majority of sound still coming straight though to the bottom.
Thinking of combining methods of reflection, diffusion, and absorption...
Maybe cutting and stacking Rockwool - leaving air/sound pockets for travel
Material Ideas: Large River Rock, Brick, ??? Open to suggestions???
Final Thoughts: No point in improving sound from the exhaust if the sound is louder from another area. I.E. It doesn't make much sense to create the best muffler in the world if the sound coming from the shed itself, exposed pipe, air/fan openings, are louder than the exhaust can if the over all goal is simply to reduce the level of sound from the entire system. You are only as good as your weakest link.
This makes me want to start this project to test and come up with the best design, but spending $2k on a shed and components, although the process might be fun, money may be better spent on buying a more quite generator in the first place in the form of a more built for purpose solution such as a true home generator from Generac or the like. I say this having just bought the Firman T07573 ;)
Use case is everything here. As a primary goal to have a large portable device and secondary to use at home in case of emergency, with costs in check, I think this makes total sense.
This project definitely got me thinking!!!
Keep up the GREAT work and Thanks Again for sharing!
I like your muffler. Your video it get us to think. I am putting a generator and shed together. What I think I will try for the muffler, this way. Smaller can with led, use the same materials for baffle, except I thing I will design it a little different. I want the flow of air with no sound. Have insulation, space, insulation with opening at 33 degrees spacing. This way the air can travel to different layers to absorb the sound. The number of layers and be modified. Thanks with great job. I like to tinker and make things, like my 63 year old car.
I want to see the V3 😁
You could use a rachet strap to secure the lid better and seal?Also thick walled pipe alone can reduce exuast sound,I remember some cars that werent verry loud with out the mufler because of the thick walled pipe before the muffler.
Good detail!
You're amazing.
Hey:) I’ve looked though some of the comments and I didn’t see you talk about leakage with the exhaust connecting to the 2” pipe coming off the engine as well as the connection to the muffler which again inserts inside of the expansion joint/2” pipe? Are you using high temp tape to make the exhaust pipe larger to fit more snug inside those 2” pipes? I would think fitting the exhaust over instead of in side those 2” “pipes” that are coming and going from the engine and muffler but I’m guessing is hindered by not having a bigger exhaust pipe available?. Thanks again:) peace
I plan to build a shed using many of your great ideas....Comfortboard, side vent baffles and maybe the Frankenmuffler.....but I will build a custom plywood enclosure 4'x4'x4' with fixed top. My generator is the same size/output as yours and I plan to operate it completely remotely (with remote control) on propane. My question to you is if you have issues with high temperature within the enclosure when you have shut the generator down after significant running and the vent fan is off? Does the heat soak cause damage to the generator plastics and the enclosure?
Unfortunately, I can't answer that question yet. I have only run the generator for a short time in the shed. Mostly, it is used off-grid when at a motocross track. There isn't much plastic on this generator, other than the control panel, so not a lot of exposure there. The shed itself is very well protected by the insulation, so, I don't think it should be much of an issue, but it will definitely be warmer in the shed that outside. Only time will tell if it has any adverse affects.
Great video! I have built the can muffler and enclosure matching yours almost exactly. My issue is the heat inside the cabinet is reaching 150F with the doors closed. Could one remove the muffler altogether and extend the exhaust from engine with an insulated exhaust pipe through the cabinet wall?
Holy cow. Id like to see the 2.0, but not to take a full hour for it. I hope you have a short version. After watching all of 1.0, a 10 minute or less summary should suffice.
You could always run it at 2x speed, and it's only half an hour. Lots of info in the 2.0 video, including parts lists and prices, and FAQs. But I do tend to ramble. On the other hand, nobody said the video was mandatory to watch. It's just there for reference in case anyone was interested in listening to my outlandish theories on generator sound attenuation, electric motorcycles, or repurposing misc. hardware into stuff it was never intended to do.
I installed a used cat converter from a car on mine so it wouldn't kill my chickens .. it also quieted it down quite a bit .. my quiet box is inside a shed , so i had to run a totally different ventilation system using inline duct fans.. you can't even hear it running .. just a slight hum , also installed a cement floor under the gen and box.
Just received my Westinghouse generator 7500/9500 love your videos. I have a shed but the generator in there died it had a different side mount exhaust so I am interested in your mods.
Great build series. Re cost of Rockwool for lining the walls of the shed. Did you need about 80 SF of Rockwool?
(4 × 6 = 24 SF each front & back x 2 = 48 SF front & back; 4 × 4 = 16 SF each side x 2 = 32 SF for sides, total front back & sides = 80 SF)
At current prices $8 to $10 per SF, now costs about $700 to $800!
I guess that depends on if you need to include shipping or not. At my local Lowes hardware store, Rockwool comfortboard is still about $60 per pack (which is 48sq.ft., or 6 sheets of 2'x4' size.) I used about 7 or 8 sheets for the shed (including the floor), and the rest was used in the muffler. So, still about $120 in my area (California). That puts my cost at about $1.25 per sq.ft. (not including sales tax). Remember, the interior is a bit smaller than the outside, so it's not a full 4'x4'x6'. If you need to add shipping for the rockwool, you could easily double the cost, unfortunately.
Cool man keep it up!
You don't need screws to hold the rockwool to the walls of the shed .. just use 3M spray glue.. the glue is much better
I'm sure you are correct. However, I wanted to make sure that the rockwool wouldn't come apart and have the outer layer peel away and have the rockwool fall on the generator. I was a bit worried that the vibration of the generator and the heat might affect a glued connection. More of a belt and suspenders approach. But good advice for those that watched the video that there are many ways to approach this.
How about attaching a small motorcycle muffler to the exhaust port, first? Motorcycle mufflers have noise cancelling properties, which create sound waves that cancel each other out. You could attach the trash-can, set-up behind the muffler. A car muffler would be too big and not have the pressure to force the air & sound into the baffles alongside the main tube.
You could do the same after your cabinet vent. You could attach a catalytic converter and cut air pollution, if you have the money.
Rather than just insulation within the generator shed; cover the insulation with sheet-metal, wood, or plastic, panels; perforated with holes. Hundreds of say, 1/4-inch-diameter holes drilled into the panel, or lesser amounts of 1/2-inch or 1-inch holes. You will have created boxes on the inside-walls. The perforated panel boxes trap the sound better. It is called a "Helmholtz Panel Absorber". The number and size of the holes relative to the size of the box created behind the panel is important to absorb low-frequency, bass, sound. You would have to it look up. They have online conversion calculators where you put in the dimensions of your inside-wall-box and hole size, and it tells you the number of holes to eliminate the low frequency sound. A panel with 1/4-inch holes will trap different frequency sounds than 1-inch holes. So, you could make several panel boxes; each with different size holes.
Dampening the air intake to the compressor reduces noise. Stopping vibration reduces noise; i.e. putting the compressor on a rubber mat or pads cut from a rubber mat; and a flexible hose metal hose for a few inches coming out of the exhaust port. A small fan blowing against the final exhaust port might break-up the sound.
I add motocycle muffler to my extra loud diesel generator. No much effect, its still ridiculous noisy but sound become more "nicer", it has now only low frequencies.
So would it be better to put the exhaust towards the bottom of the can as someone else mentioned or does it matter? What do you think?
Thanks for sharing; for your education, guess if you bury the shed like 33, 50, 66 to 100 % into the ground, will it be significant to the song levels? Now you have your trash-can-muffler vertical position, but if you have it Horizontal position, will it make any difference?? What happens if you use a car muffler instead of the trash can muffler??
I put the trashcan muffler in a vertical position for a couple practical reasons. First was rain: The muffler has a hole in the bottom where the exhaust exits, and I didn't want to get water in it. The trashcan naturally sheds water when it is in its normal vertical orientation. Second, was that placing the exit at the bottom gave me the opportunity to make the sound turn another corner and attenuate a bit more sound. Third, the trashcan takes up less space and stands up on its own in its normal vertical position. If I laid it sideways, I'd have to support it with a stand (to keep it from rolling) and also keep the lid from falling off. It also gave me the option to line up the exhaust inlet with the generator outlet a bit more directly. As far as the car muffler, I have seen quite a few videos where people tried auto mufflers on generators, and the results were less than effective (in my opinion). Car mufflers are designed to reduce sound levels at different frequencies and airflow volumes than the generators typically produce. Plus, the trashcan is many times larger than a car muffler, so it gave me the option of adding a LOT more sound-deadening material than a car muffler has available. Car mufflers need to fit under a car and be moderately aerodynamic, but trashcan mufflers not so much. That being said, this was just an idea. So, feel free to make your muffler fit your own needs in any manner you think makes the most sense. It doesn't need to be a trashcan, it doesn't need to follow my particular design, and it can be made of almost anything you can think of. A trashcan was just something that I thought might make a good muffler for my application, and it turned out to be pretty effective.
@@C5Tor Thanks for sharing!
Sorry, mistyped "horizontal" instead of "vertical" above. I corrected the previous comment to reflect why I put the can in the normal "vertical" position. Sorry for the confusion.
My understanding of mufflers is that there are baffles so that the sound has to "bounce" throughout the muffler to achieve "quiet". With your design of Frankenmuffler, it seems that the exhaust merely goes from top to bottom of the trash can and sound is absorbed along the length of the perforated pipe. With version 3 and the spiral through the system, it seems that you are achieving a sort of baffle. I realize that the more baffles, the greater the resistance of air flow, but running a straight pipe seems a little pointless. Will the spiral "nautilus" achieve the desired baffle? Asking for a friend.
There are various ways to mute the sound, and several types of mufflers. The one I ended up using is based on a straight-through design, with a perforated pipe and sound absorbing material, much like a glass-pack muffler. It has the least back pressure, with moderate sound attenuation. Most motorcycles and some cars use this method, as it is high performance, simple and tends to be smaller. (Although in my case, I went bigger.) Then there are chambered exhausts, where the exhaust takes a circuitous route through several chambers and baffles. More attenuation, but more back pressure. There are turbo mufflers, similar to the straight-through design, only the perforated pipe makes a few bends. There are reflection-style mufflers, that bounce the sound waves back at themselves to cancel certain frequencies. These tend to be pretty good performance-wise, and they are good at cancelling specific frequencies. There are also lots of combinations of the above, like resonator mufflers that combine aspects of chambered and reflection exhaust. I ultimately went with the glass-pack style design as it was fairly simple, and I'm most familiar with working on motorcycle mufflers. I also wanted to minimize back pressure. But this was just an experiment, and everyone can approach this differently. As you may have noted in the videos, the straight-through design did indeed work, even though the idea might initially sound a bit pointless. It was based on a known design. It actually worked a bit better than my Gen3 spiral design, even though, intellectually, the spiral design should have offered better sound absorption. (It probably would have worked better if I had spiraled it around one more time.) Anyway, the intent of the video was just to get people thinking of their own solutions to a common issue of quieting a loud exhaust while balancing performance. There are as many ways to approach this as there are people trying it, and that it the cool part about DIY projects.
@@C5Tor I greatly appreciate your time and effort in trying to resolve the sound issue. I appreciate EVEN MORE that you took time to respond to my question! I look forward to hearing about version 4 (and 5 and 6 ...) should you continue to persevere. God Speed and God Bless!
Great quietbox combo, very quiet and beautifully designed. Are selling by any chance? I wish to get one, my generator is loud. Please 🙏 assist?
No, not selling. Just providing some ideas for fellow generator owners to quiet down their noisy generators.
Good work Sir. I am requesting that you share the the three pages of parts information in a readable format. Most of what is there at 25:40, 28:34 and 31:04 is blurry and non-readable. I cannot even come close to what the 3M product is, actually. Please help by posting a link to clear readable parts lists.
Sorry that those pages were blurry for you. You might want to take a look at what your UA-cam video quality is set to. (Click the gear icon in UA-cam for settings.) If it is set to Auto, you might want to bump it up to 1080p. Those images seem pretty readable on all of my devices, even down to 480p on my phone. Definitely turn it up to 1080p, and it should be readable. The parts described weren't specific links to those parts, just pictures of the items that I used. This was so that interested people could find something similar if they wanted to try that route for their own builds. So, there really isn't a list of links to share. Hope that helps.
@@C5Tor Thank you. Stupid me---never thought it would default to 360 so I did not check. I won't make that mistake again. Meanwhile I have most all of the parts ordered and arriving. Found the Suncast shed on sale at Lowes for $269----comes in a Craftsman Logo'ed box but actual shed says Suncast. I hope others will find this deal. We don't have a good supply of Rockwool but I found some Cavity Rock locally which I will pick up. Also, can you tell me how many of the 24"x48" batts that you used? Thanks again.
I think I used 7 or 8 24x48 sheets. Hard to remember now after 4 years. I used some for the shed, and some for the muffler(s) (I made several prototype mufflers.) I probably answered that a few times in the earlier comments, but not able to find it at the moment. (Wish UA-cam comments had better search capabilities.)
Excellent video. Did you consider ceramic fiber blankets for the muffler. Much more affordable than rockwool and it's pliable. Supposedly it also has very good acoustic absorption properties. Regardless your project has the best sound dampening properties of any video that I've seen. Thanks.
That would probably have worked as well. However, I already had some Rockwool, so I used it.
As a retired Construction Supt / Engineer you did a good job.
Could you use a large capacity car muffler?
I remember my parents 1960 Ford Station Wagon with a 390 V8 and it didnt make any noise.
Note I am 72 now so maybe my memory is off a little on the noise LOL.
Best Regards
Thanks so much for this. Did you consider putting the "inlet" 3 or 4 inches lower on the can so the insulation above the mesh pipe is thicker? So that the "lid" becomes something 5 or 6 inches thick.???
Yes, I did consider moving the inlet down a bit to get a thicker "lid" to dampen the sound out of the top. It probably would have been the way to go. At the time, I was trying to maximize the area below the bend, since the bend itself was kind of "wasted" space. The inlet pipe and the bend are not perforated, so they didn't let out quite as much sound. I was trying to maximize the amount of insulation around the perforated pipe section.
@@C5Tor OK, I get it. So my story: A neighbor has launched a "lunch wagon" business with her two daughters. The wagon moves around, has a fb site and the community is enthusiastic. On Saturday the generator, attached to the front of the truck was so loud they had trouble taking orders. I have a 55Gallon Drum in good shape that I literally picked up on the road. So my thought is to build from the top up (upside down) then weld a grid from rebar on the bottom - holes in the side on the bottom etc. then flip "Upright." Not having tried any of this before I don't know if it'd be worth it. Won't cost any money. But... Is the noise damper that much with this technique/system? She'd need to store the drum and "wheel" it. I may have difficulty convincing them of the improvement.
I think I made the point in the video, but remember that the exhaust is only part of the total noise produced by the generator. So putting a muffler on the exhaust only reduces part of the noise. This is why you often see videos of people that put car mufflers on their generator, but it is still just as noisy as it was to start with. The exhaust is quieter, but the rest of the generator is still banging away. That is also why I quieted the rest of the generator using the shed, and then did the exhaust last. A lot of mobile food vendors go with something like the ZombieBox, which are nice, but pricey. The solution I showed in my vidoes was really a poor man's zombie box with a lot of found parts and better ventilation.
@@C5Tor yes. My friend’s plan is to just buy a new (generator). I hope to talk them into an eventual “dedicated” trailer for a box/muffler combo. Time will tell.
Is the muffler can really necessary? If you put a few more baffles into the exhaust port, wouldn't the fan remove the exhaust and noise out your baffle box and be just as effective? Or am I not considering something? 🤔
You definitely want to get the exhaust out of the shed, and not let it exhaust directly into the shed. Most of the heat is in the exhaust, and all of the CO/CO2. The fan struggles enough keeping the shed cool without adding a lot of extra heat to the shed in the form of exhaust. The added carbon monoxide will make the generator run poorly and may even cause it to turn off. You don't have to go to the extreme of using a trashcan as a muffler, as this was just an experiment to see if it would work (which it did).
All these ideas are good and I like them. Questions are: does the exhaust cause back pressure on the engine?
From what I have found out, any modification to the exhaust cancels the warranty. Your opinion?
We lost power and wife finally approved to get generator (and she paid for it!) after me nagging her for months. It was nice having electricity when it failed, but I felt terrible being loud with my neighbors (they are 100 ft away so that is good at least. Awesome work!
My question for you? What part of the project attenuated the sound the most (Box or muffler or some other part?) I don't need to make it as quiet but am looking at building a 3 sided covered box (with MLV and rockwool to decouple the MLV) and having the open end out toward the direction were no one lives. I think I just need to loose about 10 dB (your system looks that it looses 20 dB) in the directions of my neighbors. Thanks!
From my perspective, the Rockwool helped the most. The baffles on the sides were effective as well. The exhaust was the next loudest thing, but it was directional. So, I could have just pointed the exhaust up or away if I needed to. But since I'm in a residential neighborhood, there weren't any directions that were unoccupied, which is why I went with a muffler. If you can get away with it, a three-sided box would certainly help you in terms of ventilation, and it wouldn't have the heat and exhaust issues I have with an enclosed box design.
@@C5Tor thanks for the reply and information. I think the 3 sided box will be the answer as we have side neighbors but no rear ones (lakeside). The leftover MLC and rockwool will come in perfectly. I will probably build the shed from metal roofing sheets from the big box stores and just make the 4th wall lightweight to seal it when not in use.
Sorry another question, thought about going to NG? We had another failure last week so thinking about it. Our WC is only 6" at service and my model say 7" min :-(
Did you actually have a question? I haven't used this generator with natural gas, I just noted in the video that there was an option to run it on natural gas if needed with an aftermarket natural gas adapter.
@@C5Tor that is a question, ask if you thought about switching. I want to get off propane after burning through most of my tanks the last outage. Turns out pressure here for gas is low.
Thank you for the amazing video and instructions. Question I have is - do you have any issues with CO shut downs in the small enclosure even with fans and inlet?
I haven't had any issues with CO causing shutdown. Theoretically, the fan has a high enough flow to replace the air in the shed every ~4 seconds. Also, almost all of the CO generated by the combustion in the engine is being directed outside of the shed via the exhaust.
There's 2 details I didn't catch. In your muffler... where does the exhaust pressure go? I don't see any outlet. The back pressure would be terrible. You must have some way for the exhaust to exit. And... I see the rockwool liner & top, but what is in-between? What are those details?
The exhaust goes out a hole in the bottom of the trashcan. I did an earlier video on the original trashcan muffler build. you can see video here: ua-cam.com/video/jZpRSenXJAs/v-deo.html
Not sure if I understand the second part of your question. The rockwool is attached directly to the inner walls of the plastic shed by screws. The acoustic vinyl is attached to the under-side of the lid via adhesive. Perhaps you could clarify what "in-between" you were asking about?
@@C5Tor ... I saw the Rockwood disk on the top & the exhaust pipe going down into it. Underneath that... is there baffles, or loose fiberglass batting, or just air all the way down? What is in-between the top & the bottom of the can?
That is all explained in the previous video I listed above. The middle of the trashcan is filled with loose rockwool batting instead of the semi-rigid stuff. All in all it adds up to about 20 lbs of insulation filling the trashcan.
I am planning to extend the exhaust in my Westinghouse 7500 and just ordered a 3/4 tap before seeing stage two. I can return. Your welding option for me is not feasible so I was wondering if I could still use the 3/4 inch exhaust stub and use a reduction bushing or series to increase the overall diameter to 2 inches. Or do they make a 1 inch tap?
It depends on the size of the muffler. These generators seem to have come with several different sized muffler outlet openings. Mine was not big enough to use a 1" tap, which is why I had to go with the 3/4" tap. Tapping and welding are just two methods that you could use. I just showed what I used in my build as ideas for others. I've seen lots of ideas, like pressure fittings or magnets. It sort of depends on how sturdy you need the connection and how airtight you need the fitting. Also keep in mind that that location is probably going to be the hottest part of your exhaust, so you need to worry about how heat will affect it. The metal will expand and contract due to heat, so take that into account.
Nice project and ingenious use of a garbage can to home brew a muffler. But since you are already going to a muffler shop to weld up.a connection to the generator muffler, maybe simpler to just have the shop add a length of muffler pipe and an automobile muffler instead of messing with the garbage can. Do you think this is a reasonable option?
You could certainly go the auto muffler route, and I see that lots of people have tried it. However, if you look up "Generator Automobile muffler" on UA-cam, you will see that most of the experiments were really less than satisfactory. Either the car muffler made little to no difference, or it was a lot of work with welding, etc. Usually both. Quite a few posters seemed to indicate it wasn't worth the effort. My take on this is that car mufflers are really made to work on larger volumes of air moving at higher velocities, and they are designed to muffle different sound frequencies than you would get on a small generator engine. Most of them use baffles to reflect the sound rather than absorbing it. The car mufflers that use sound absorbing materials (glass-packs) don't really have enough sound proofing materials to significantly reduce the sound much. This trashcan muffler concept takes the glass-pack idea, but adds a LOT more sound absorbing material than a typical car muffler. (Maybe 10x or even 20x more!) Imagine if your car muffler was the size of the trashcan, and think how much quieter it might be. This was the idea behind the trashcan muffler. While the car is limited on space to put a muffler, my generator shed doesn't have that limitation; it can be large, ugly and non-aerodynamic. The second area of concern is that most of those experiments I saw in the videos seemed to try adding the car muffler WITHOUT any other efforts to soundproof the rest of the generator. So, even if the car muffler might have been moderately effective at muffling the exhaust, the rest of the generator was still so loud that they couldn't hear the difference. I talk about this in the video when I discuss doing the muffler last, after quieting the rest of the generator. But feel free to experiment. That was the point of this video, after all. Just sharing ideas for folks trying to quiet noisy equipment. Good luck!
How to make it sound like a hemi?
IMO, instead of spiral. Why not stagger the layers with the holes at 180° and angle them at 30-45° down. For flow pressure test, perhaps get one of those hand held wind speed gadgets then stick a blower on the other end. That should give a good estimate of flow rates and back pressure of your various design.
You could also try some foil backed mineral wool to wrap the outlet pipe from the wall and also the shed since the metal pipe might attenuate the noise from the shed.
Question, can you use a 1-inch Conduit Compression fitting to connect the generator exhaust to the flex pipe instead of welding some type of connection onto the generator? I wonder how well electrical conduit handles high heat. I am building the muffler now but I have not welded or done anything to the generators exhaust pipe. By the way, I have the exact same generator that you have. It is a beast of a generator and I love it.
There are lots of ways to connect the pipe. The ones I used are just ideas. The problem with this particular generator is that the exhaust outlet is a bit oddly sized. The ID is 1", but the OD is like 1 1/8", so I didn't have much luck finding any off-the-shelf components that would fit snuggly and also were slim enough to clear the heat-shield without having to modify the heat-shield. If you don't mind cutting or removing the heat-shield, you would have a lot more options. I've seen people in various videos use everything from magnets to J-B Weld to dryer vents, etc.
What if you left exhaust as factory could the exhaust fan move enough air to keep the carbon monoxide from shutting off, or is it due to the heat from exhaust that it needs to come out of shed
Several factors. CO buildup was a factor as well as heat. Heat was probably the major concern, as the exhaust can get to hundreds of degrees vs. the rest of the generator. I needed that heat to go outside. Then I also knew I needed additional sound attenuation for the exhaust energy, hence the trashcan muffler. But it also gave me the option to do things like control the direction of the exhaust (like point it up in the air or down at the ground) or pipe it away from the shed or windows, etc. The fan should theoretically be able to replace the air in the shed every 4 seconds. But we all know that airflow isn't that simple. The air stream would have probably ended up getting sucked into the inlet, travel directly across the generator and out the fan, staying mostly in the middle of the shed. The top, bottom and corners of the shed would have stayed pretty stagnant and built up CO and heat, until the generator shut off or the fan overheated or both. That was my theory, anyway.
I see you are using the Westinghouse WGEN 9500 which has a remote start/stop fob feature. Does the remote work properly when the generator is in the shed with doors closed? Great videos by the way. I have learned a lot.
Haven't had to use the remote yet. I probably wouldn't use it in that way in any case, as I would typically be standing at the generator, turning on/off the propane, plugging in cords, checking exhaust setup, confirming fan startup, etc. But I've seen on other videos that the range for the remote is quite a long distance. I'd just worry more about turning on the propane/gas, as I do not leave them turned on when not in use.
Do you leave the trash can setup like that in outside? Does it get rust?
I do leave the garbage can muffler outside of the shed, as I have nowhere else to store it. But the can itself is galvanized, and I actually put a garbage bag over it, so it seems to be holding up fairly well. The rest of the hardware, like the exhaust pipe and the baffle boxes fit in the shed with no problem.
@ I’m replicating what you did and almost done. Will test to see when I’m done. So nervous. Thank you for all the info btw.
Good luck with your build. Keep in mind all of this stuff was just an experiment. I had a few ideas, and I had some time to kill during Covid to test out some of those theories in real life. The point of the video was to give a few ideas on things to try or strategies that might work for others. It wasn't really intended as a definitive blueprint per se. Anyone can implement the ideas in their own way using whatever materials they might have access to. Things like using a trash can for a muffler were just examples of things you could try. So put your own spin on it and make it fit your own needs.
First of all, thank you for a great video of a great generator shed. I am in the process of doing one very similar and am also planning to use the Rockwool board on the floor, but I am concerned about the vibration of the generator breaking the rockwool down since I believe it is somewhat brittle. Have you experienced that?
The rockwool isn't really brittle. It is fairly soft. Vibration isn't going to affect it much. You can't roll a sheet of rockwool board up into a cylinder, but it is soft enough to bend a bit. You can also walk on it. I haven't seen any indication that it would break down.
@@C5Tor Thanks!!
what is the temperature of your generator when the box is close ?
didn't see any measurements of heat
Haven't really had a chance to use the shed in anger yet, so haven't done any extensive temperature testing. I did rig up some remote wireless thermometers, though so that should help keep an eye on things if I do use it. The shed does get hot just sitting in the sun, but the insulation actually helps quite a bit with that.
@@C5Tor i really want to know the temperature of the box open vs close with generator working, vs box in idle mode with generator not working
it will be very help to me and anyone that want to try build box like that..
also if you can explain why you chose "rook-wool" and not "fiberglass-wool"
or why you didn't use "drywall-soundboard" or "polystyrene foam panels"
all this information will be very helpful
maybe you can do another video on all this stuff that people can decide what is best for them from your experience
The rockwool was really ideal for this application. It is fireproof to 2000 degrees F, while the fiberglass melts at a much lower temp. Rockwool is also resistant to mold, and doesn't turn to mush when it gets wet. Additionally, rockwool panels are already used in sound dampening applications because it is much denser than fiberglass. I wanted something that dampened the sound but was going to be fireproof. The other items in the list were really not as good in either the sound attenuation or fire-resistance categories.
So i have a question about part the you welded on. The one you mentions is the "end of a 1 inch pipe". I keep looking at the ones availabe at home depot, and at Lowes. They are temperature rated for as low as 250 degrees with the highest i've found being 400degrees. Did you weld one that is rated higher and if so , if you don't mind posting links in your reply, or notes.
I actually used black iron pipe, which should easily handle over 1000 degrees. I polished it up to make it look pretty, but it will oxidize pretty quickly. Galvanized pipe can actually handle fairly high temps, but the zinc starts to melt at around 400 degrees, so I think that is the reason for the low rating. Zinc fumes can be pretty nasty, although there wouldn't be much zinc on such a small piece of pipe. But it is a good question I didn't really take into account on the build.
I wonder about putting the exhaust into a big barrel of water, sounds crazy but I think the water would be very effective at taking the kinetic energy out of the exhaust
I actually went into that very topic at the 43:00 minute mark in the video. Those are just my thoughts on the technique. Here's a direct link to that part of the video: ua-cam.com/video/y3pUw408jCU/v-deo.html
@@C5Tor valid points. I think the loud glugging sound and the back pressure can be solved. The intensity of the glugging sound must be proportional to the size of the bubble. Therefore reducing the bubble into lots of small bubbles instead of one big bubble should solve this. A pipe with lots of holes in a trough of water. This might also reduce back pressure.
my generator is in a brick shed with a pipe going through the wall into a 25 litre tub of water. the water cuts the exhaust sound to almost nothing
I figured you didn't see my reply to your reply. so i'll go ahead an ask it as a separate question: Would it be ill-advised to put a fan that blowing air inward on the 'vent side'? So you have one fan blowing in air and the other one blowing out?
I'm not actually sure if it would make much of a difference. While it probably wouldn't hurt to add an incoming fan, I don't think it would substantially increase the speed or volume of the air exiting the fan outlet. That outgoing fan is going a constant speed, and I'm not sure if it would really speed up that airflow at all. In other words, if the air has nowhere to go, it doesn't help to push more air into the shed. I think a better solution would be to add a second outgoing fan, which would increase the airflow by increasing the area of the outgoing vent, thus allowing more air to exit the shed. Just my perspective, of course.
Did you do any temperature testing of the exhaust manifold with and without the frankenmuffler? Great job here !
Unfortunately, haven't had much chance to do temperature testing. I guess that is a good thing, since it means my power hasn't gone out yet.
@@C5Tor Just wait until you need to run this on a hot day .. double up your fan cfm .. thank me later
Has anyone ever tried a complete motorbike exhaust, off similar hp engine?
Hey could you comment on the direction of air flow from both sides of the mini-shed. Is the attic fan on the right blowing air inward or outward? and Also the other side is it just a vent or is there an actual fan on that side?
The air comes in through the vent on the left, and exits out the fan on the right. The fan is blowing outward, as most attic fans do.
Thanks for responding. I have a follow up. Would it be ill-advised to put a fan that blowing air inward on the 'vent side'? So you have one fan blowing in air and the other one blowing out.
@@KeithOlbermannn it's best to do it as he did. If you vent is to small and the fan is drawing air in, as you asked, the fan would be prevented from flowing at it's highest flow rate. Plus it can create air pockets at the roof area of the shed. If the fan exhausts hot air it will have a better chance of drawing the hot air from all parts of the shed via turbulent mixing of the incoming air from the vent. It's always a good idea to look up the basic math to figure out if your vent will the near the same CFM of fan, or a little more. I can't recall the formula off the top of my head, but they are a bunch of places with it. Some even have calculators to figure out CFM of a given vent hole size. This will ensure the fan does not draw excess current, and become a safety hazard, while ensuring it cools effectively.
Wow. I have that exact generator, bought a very expensive sound deadening generator box, & it only lowers it 25 dB. Code requires I drop it down to 48 dB total, a drop of 42 dB. I've found most of the noise is coming from the 2ndary muffler, so your garbage can modification is going to solve my problem.
And ... your shed mod did exactly what my purchased sound box accomplished for about 1/10 the cost. I feel dumb.
Good luck with your project. I'm not even sure if 48dB is possible, unless you are in a very rural area with lots of nice sound absorbing vegetation. In my suburban neighborhood on a quiet day with no traffic in the street, the ambient sound level is in the low to mid 50's. You can see this on some of my earlier videos with my sound tests (see my channel for more vids). Birds chirping and a slight breeze are louder than 48dB. I guess if you only run it when the power is out, and you share some electricity with the neighbors, they won't complain too much.
@@C5Tor ... I have a 10,000 ft² yard with lots of hedges, but reaching even 52 dB is impossible at my property line. The ironic thing is I live on a busy street & it runs @ 63 dB most of the time. My city's Code Enforcement department is famous for being completely unreasonable. So... I try.
Question, what was the cost and time for this set up?
The cost of all the parts is discussed in the Frequently Asked Questions section of the video, towards the end. It also has a breakdown of all the parts I used. Time can vary, but it took me about a week to put everything together.
How did you attach the blast gate to the shed?
I drilled a 6" hole in the shed with a 6" hole saw. Then used screws with large washers to hold the blast gate to the inside wall of the shed. The screws didn't go through the plastic of the blast gate, otherwise it would have interfered with the operation of the sliding gate. The screws were just "next" to the blast gate, and the washers hold it in place. I followed up with some foam insulation around the hole to seal the edge and make it waterproof.
@@C5Tor Thanks
Definitely listen at 2x speed. Normally I do 1.5x, cause 2x is too fast. Not the case here. But good video 👍
Parts list at 25:03
Do u have ATS?
I assume you mean an Automatic Transfer Switch (ATS). In my case, no. I have a simple manual transfer switch with a generator interlock kit installed so that you either have the mains or the generator selected, but not both at the same time.
It's hilarious that they called you an idiot when they're not smart enough to realize you were using the helmet to film. 🤣🤣
At what point dose he start it and let us here?
If you are asking about the video where I demonstrate the shed and the exhaust, it was linked in the description. You can also see it here: ua-cam.com/video/CKQu_Pvdh0I/v-deo.html
Spark arrestor is not needed and actually a huge hindrance of free flow. A spark arrestor is not needed in non woodland applications……
This being California, it is unfortunately required at many OHV parks and camping areas. This is for a woodland application, when I take the generator with me dirt bike riding. I wouldn't run it at home, and only put one together to make sure I was compliant when asked by park/forest rangers. Best to be prepared. And if I have to run one, might as well do it right.
Lot of info... didn’t hear the generator...
next step is to put the garbage can underground
Here we go , mini garbage can muffler, and to think I used my mini can little can for dog sh💩t. This is much better.
All that talking and we didn't get to hear it run
Surely everyone watching would have wanted to see/hear this
There are several more videos in the "Quiet Generator Shed" series on my channel. A couple are listed in the description of the video. There are also a few more videos on the channel that are just sound tests with various levels of sound dampening.
Here is the original video:
DIY Quiet Generator Shed Project video (Shed tour with sound tests): ua-cam.com/video/CKQu_Pvdh0I/v-deo.html
As if electric cars weren't bad enough...electric dirt bikes LOLZ
Love my electric dirt bikes! For myself, it really put the enjoyment back into dirt bike riding. Almost no maintenance, no oil changes, no air filters, no smelly gas to leak all over or gum up my carbs, no waiting for the bike to warm up, no burning body parts on hot exhaust pipes, etc. The riding experience is very zen, with no need to shift or bog the bike or worry if I am in the right gear. Your feet are always in the right placement on the pegs, because you don't have to worry about the shifter or the foot brake. Getting into the flow of the trail or the track is super easy. Just turn them on and ride! Both gas and electric bikes have their own pros and cons. The main weakness of the electric is range and charging speed. For everything else, I think the electric is superior, at least for my needs. But to each his own.