# Generator exhaust ext.



## Bulldogger (Feb 19, 2021)

The outlet of my dual exhaust measures at about 1 3/4 inches. I need to connect an exhaust extension to the mufflers to vent exhaust out of a generator shed. I need suggestion on adapters to connect to muffler and preferably stainless steel exhaust tubing at least 1 3/4 diameter.


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## Bulldogger (Feb 19, 2021)




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## Jackruf (Nov 4, 2012)

Check this website. Their card came with the magnetic dipstick I ordered through Amazon. Know nothing about them otherwise, but seem to have what you are looking for.






Welcome - GenExhaust.com


We provide generator exhaust extension kits for portable generators. Run your generator safely within your garage or building and vent the fumes outside.




genexhaust.com


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## Jackruf (Nov 4, 2012)

Looking at their site closely, I think 1 1/2“ may be largest size tubing.


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## FlyFisher (Jun 30, 2018)

Bulldogger said:


> I need suggestion on adapters to connect to muffler and preferably stainless steel exhaust tubing at least 1 3/4 diameter.


You might check with some marine suppliers that cater to sailboats.

A common add-on to sailboats is an "arch". They are used for everything from bimini top supports that house solar arrays to aft jib cranes for holding dinghys high and dry. They are custom jobs. And they are all welded stainless tube designs. 

I would venture a guess that you can get what ever size tubing you need bent however you need it, if you need it bent, from one of those such shops.


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## iowagold (Jan 22, 2020)

Bulldogger said:


> The outlet of my dual exhaust measures at about 1 3/4 inches. I need to connect an exhaust extension to the mufflers to vent exhaust out of a generator shed. I need suggestion on adapters to connect to muffler and preferably stainless steel exhaust tubing at least 1 3/4 diameter.


easy to do.
for the tube go to summit racing for the stainless tube.

mc master carr for the high temp silicone connection tube as vibration isolation.
let me know if you need links.


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## exmar (Jun 29, 2015)

Know nothing about extending exhausts, but it seems that a car exhaust shop in your area could bend any type of pipe (probably have in stock) to your specs. Make sure that it slopes to the outside or otherwise protected from rain coming in.


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## iowagold (Jan 22, 2020)

we shoot the exhaust up and use the rain hat for a gas water heater.
and yes it works the best if you can get it up high for the noise.

and use baffle screen punch plate cone to stop the trumpet noise.
pm if you need links for those.

yea stainless might be a trick from some muffler shops...
it takes a water form bender to bend or form them...


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## Ataraxius (Jul 21, 2021)

*POSSIBLE LOW COST SOLUTION?*

If the muffler is flat with an exhaust port that only sticks out 1/4" or so, you won't be able to connect anything directly to it. There's just not enough sticking out to grab on to.

If that's the case, you might try using 3" *stove pipe.* Place a 3" elbow against the flat part of the muffler where the exhaust port is located and secure it with springs & heavy wire to keep it in place. The springs and elbow are important. The springs will hold the elbow flat against the muffler but also allow for some movement when the engine bucks or vibrates. Then add straight pipe to carry the exhaust away. Try to gimbal the straight pipe as additional allowance for engine bucking.

This will leak exhaust slightly so it's not suitable for an indoor application but might be OK if your gennie is in, say, an outdoor sound-proof enclosure with good ventilation.

A variation might be to use a 4"-to-3" reducer against the muffler with the 3" male end into the 3" elbow.


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## iowagold (Jan 22, 2020)

90% of the time we use an adapter to bolt on and muffler extension so we can use the silicone hose.
and the other 10% we weld on a nipple to the muffler for the silicone hose.

then use triple wall vent pipe.


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## drmerdp (Apr 10, 2018)

On my old setup, I welded a pipe to the generators muffler. The exhaust system pictured was rubber mounted for compliance and vibration and slipped over the welded pipe. I wrapped to keep the heat in the pipe and out of the enclosure. Worked well.


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## Bulldogger (Feb 19, 2021)

Jackruf said:


> Looking at their site closely, I think 1 1/2“ may be largest size tubing.


 Yep. I need a bit bigger. Thanks


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## Bulldogger (Feb 19, 2021)

iowagold said:


> easy to do.
> for the tube go to summit racing for the stainless tube.
> 
> mc master carr for the high temp silicone connection tube as vibration isolation.
> let me know if you need links.


 Thanks. I found what I needed a summit. Should be here today.


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## iowagold (Jan 22, 2020)

yup summit has bailed me out more than once!
ultra fast shipping as well.

also look at places that have hydro former equipment.
we have one 90 miles from me..
cool for one piece exhaust that looks like a header with out welds to keep the flow perfect and noiseless.


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## Bulldogger (Feb 19, 2021)

iowagold said:


> we shoot the exhaust up and use the rain hat for a gas water heater.
> and yes it works the best if you can get it up high for the noise.
> 
> and use baffle screen punch plate cone to stop the trumpet noise.
> ...





drmerdp said:


> On my old setup, I welded a pipe to the generators muffler. The exhaust system pictured was rubber mounted for compliance and vibration and slipped over the welded pipe. I wrapped to keep the heat in the pipe and out of the enclosure. Worked well.
> 
> View attachment 9771


 What's that an extra muffler on the back of your shed?


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## iowagold (Jan 22, 2020)

try this
*click here for the exhaust vortex search on summit*

*they help hold down the trumpet noise.
we place them near the end of the exhaust maybe 12 inches from the end*

super low back pressure.
we use them on the race cars as well.
or if you want to tame a glass pack car exhaust they work great!
they came from nascar and oval racing and drags to help lower the db noise.


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## drmerdp (Apr 10, 2018)

Bulldogger said:


> What's that an extra muffler on the back of your shed?


Its a magnaflow I had lying around the shop.


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## Bulldogger (Feb 19, 2021)

Ataraxius said:


> *POSSIBLE LOW COST SOLUTION?*
> 
> If the muffler is flat with an exhaust port that only sticks out 1/4" or so, you won't be able to connect anything directly to it. There's just not enough sticking out to grab on to.


 It sticks out about an inch. However most of the exhaust is about 1.5 inches or so and it flares on the end to 1.75 for only an 1/8 of an inch. That 1/8 of inch is really where my clamp is holding. I think I either need more area to clamp or some way to seal the area behind rear of the 1/8 flare.


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## Bulldogger (Feb 19, 2021)

drmerdp said:


> Its a magnaflow I had lying around the shop.


 Does it help reduce the noise?


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## drmerdp (Apr 10, 2018)

It did reduce some. Most of the noise comes from the engine block itself. That’s the beauty of the enclosure Especially combined with sound attenuating of materials.


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## Bulldogger (Feb 19, 2021)

drmerdp said:


> It did reduce some. Most of the noise comes from the engine block itself. That’s the beauty of the enclosure Especially combined with sound attenuating of materials.


 If you need your enclosure to reduce noise more, the fan would need to not blow straight out. Sound below 300Hz travels in all directions. Above that frequency it travels in a straight line. My generator seems to be mostly producing noise around 1150Hz, straight line. Design the box is such a way that all exhaust and all intake would have to make a turn before intake or exhaust. Your exhaust is making a turn which is good. Sounds like your design works well for smaller generators. I'm fairly certain it would not do much for mine because of the noise level and engine size. 

If you notice the design of the Zombie box, you'll see a vent at the bottom on the inside of the enclosure and on the same side the vent is on the top opposite side, outside the box. That's what they appear to be doing. Most of the air has to go in straight, go up, turn and go out. The fan has that dome on it so any sound coming in a direct path out of the enclosure has to hit it and turn and go out. The way they have to fan mounted is not just to keep the rain out. That could be improved by either the use of a viscoelastic material like Green Glue or by adding mass most likely.


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## JRHill (Nov 19, 2020)

exmar said:


> Know nothing about extending exhausts, but it seems that a car exhaust shop in your area could bend any type of pipe (probably have in stock) to your specs. Make sure that it slopes to the outside or otherwise protected from rain coming in.


I have my Miller Bobcat inside the shop. I use it for, obviously, welding but since we are off grid it is also used for high loads like the planers and as a secondary backup to the primary EU7000is for charging the batteries when needed. It also works great to heat the shop quickly in the winter (wink) but its not very fuel efficient.

I went to a private muffle shop in the small town closest and the guy bent a 4'x 1.5" pipe (just a single 30d bend) to route the exhaust out the side of the pole barn. I have a flapper on the end of the pipe as it points up. It is aluminized pipe and in 9 years has no sign of rust except for right at the end where the flapper is clamped and is not visual. The only annoyance is the flapping of the cover when the welder is at low idle between passes. Oh, and I've had to rebuild the flapper 3x.

Have no idea why you want stainless unless for show and your going to polish or brush it.

As for noise, at least on this unit, the 'whirring' of the alternator is louder than the engine. It's just time to use some squeezy ear plugs but its too late anyway - the DW says I can't hear her.


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## tabora (Sep 6, 2018)

Again , I caution to be VERY careful with small generators being run in ANY enclosed space where humans or pets could be exposed to CO (carbon monoxide). A small generator makes as much CO as 450 cars.


https://www.cpsc.gov/s3fs-public/PresentationSAE_SETC.pdf


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## drmerdp (Apr 10, 2018)

Bulldogger said:


> If you need your enclosure to reduce noise more, the fan would need to not blow straight out. Sound below 300Hz travels in all directions. Above that frequency it travels in a straight line. My generator seems to be mostly producing noise around 1150Hz, straight line. Design the box is such a way that all exhaust and all intake would have to make a turn before intake or exhaust. Your exhaust is making a turn which is good. Sounds like your design works well for smaller generators. I'm fairly certain it would not do much for mine because of the noise level and engine size.
> 
> If you notice the design of the Zombie box, you'll see a vent at the bottom on the inside of the enclosure and on the same side the vent is on the top opposite side, outside the box. That's what they appear to be doing. Most of the air has to go in straight, go up, turn and go out. The fan has that dome on it so any sound coming in a direct path out of the enclosure has to hit it and turn and go out. The way they have to fan mounted is not just to keep the rain out. That could be improved by either the use of a viscoelastic material like Green Glue or by adding mass most likely.


The zombie box is a neat idea but also not particularly functional nor is it a long term storage solution. But updraft ventilation is highly effective. On my old enclosure in the picture the intake has a weather hood, but I never installed one on the exhaust. It’s very quiet already. The enclosure is lined with Mass Loaded Vinyl which made a huge difference. The whole package generator and enclosure is over at my sister in laws house, continuing to function Like a champ.

For my current setup I have weather hoods in a box ready for installation, bu it’s sooo quiet (EU7000s) that I havnt pulled the trigger. The fan is louder then the generators. I might still install the hoods one day. Honestly the hoods take away from the aesthetics of the enclosure, which is main Reason why I haven’t installed them. Silly, I know.


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## tabora (Sep 6, 2018)

JRHill said:


> My Tabora, despite all your posts you are WrOnG.


No, I am not wrong. I am merely passing along information from the CPSC, CDC and others who are TRYING to save lives by publicizing the extreme danger of running small engine generators inside a structure. See the Safety Alert attached.

Federal agencies like the CPSC and CDC offer guidance about proper portable generator use. They advise consumers to operate portable generators outside only and keep them at least 20 feet away from the home, facing away from all structures. They urge installing battery-operated carbon monoxide alarms near every sleeping area and testing them frequently.​​And in 2007, the CPSC passed a rule requiring portable generator manufacturers to warn consumers about carbon monoxide through mandatory labels with pictograms and phrases like *"Using a generator indoors CAN KILL YOU IN MINUTES" and "NEVER use inside a home or garage, EVEN IF doors and windows are open."*​​But these warnings alone aren't always enough to prevent user error.​​Only 15 of the 526 carbon monoxide deaths caused by portable generators in homes between 2004 and 2013 resulted from machines being used outside. In most fatalities, the generators were being used in an indoor basement, garage or "non-basement living space."​​Warnings about carbon monoxide exposure from portable generators are mostly local and seasonal. Seifer said she had read articles over the years about families in her county who had died from carbon monoxide poisoning but had not encountered any public service announcements about the dangers of exposure from portable generators.​​Issues also arise from the fact that portable generators are not meant to be used in the rain but are most commonly needed in response to weather-related power outages. People may also prefer to keep their generators inside or close to their homes to prevent potential theft.​​Henretig said that while it is important for people to use their portable generators properly, the best possible scenario would be safer machines that prevent user error in the first place.​​CPSC documents describe a "hierarchy of approaches to control hazards," in which warnings about product dangers are, perhaps unsurprisingly, less effective than designing out the hazard or protecting consumers from it. Communications like warning labels and PSAs, they explained, are last resort measures that should ideally be deployed not on their own but alongside efforts to make the products themselves safer.​​​


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## OrlyP (Oct 19, 2021)

Does anyone have any idea how to extend the exhaust on this gen? I must admit, it's an unusual design, having two exhaust ports. 

I plan to build a shed around it to lower the noise.


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## tabora (Sep 6, 2018)

OrlyP said:


> Does anyone have any idea how to extend the exhaust on this gen?


And the generator make/model number would be??? 

That said, a shed needs lots of airflow for the heat, so all you have to do is point the exhaust directly at the exhaust fan and it will be carried out with the airflow.


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## drmerdp (Apr 10, 2018)

Dual exit muffler on a single cylinder engine… lol.

You don’t really need exhaust extensions If you design the enclosure properly.


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## jeb (Feb 16, 2021)

The resurrecting of this thread brings up some questions to mind:

1. Why the plastic storage box (other than low cost)? Why not metal studs and corrugated sheet goods like you have on metal garages, etc? Seems like the plastic is a potential heat issue with exhaust, etc...espeically if you have a malfunction with your exhaust fan.

2. Moisture / condensation issues for storage. How is it in the plastic boxes? I always worry about storing my genset in those all the trapped moisture. How do you mitigate that?

-J


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## iowagold (Jan 22, 2020)

OrlyP said:


> Does anyone have any idea how to extend the exhaust on this gen? I must admit, it's an unusual design, having two exhaust ports.
> 
> I plan to build a shed around it to lower the noise.


i would remove the muffler from the gen set and make a flange pipe for the engine for an external to the gen set muffler.
and might even retrofit a honda eu7000is muffler!
you would need a fan to cool the muffler.
but the noise is way down from any thing else out there right now.
and a gen stack exhaust vent up in the air.

and if you go the shed way i prefer concrete and steel for a gen shack...
you can set it up as a faraday cage and bunker shed..
in our area of the country we get winds over 100 mph in storms.
so ultra heavy duty for me is the way to go.


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## OrlyP (Oct 19, 2021)

tabora said:


> And the generator make/model number would be???
> 
> That said, a shed needs lots of airflow for the heat, so all you have to do is point the exhaust directly at the exhaust fan and it will be carried out with the airflow.


It's a Blackstone BS6800D-SSC. Suffice to say, it has a GX390 clone engine. The shed design is not really the issue. I already have a sketch of what it would look like, including where the openings will be (see below). The interior will be lined up with sound-absorbing material (rockwool boards, fiberglass sheets, or whatever is available to me). It's still a work in progress but all that is going to be moot if I don't figure out how to interface a pipe extension to that muffler.



drmerdp said:


> Dual exit muffler on a single cylinder engine… lol.
> 
> You don’t really need exhaust extensions If you design the enclosure properly.


Wether to discharge the exhaust gases externally or within the shed then rely on the fan to pull it out, is debatable. I for one would prefer the former. The "Don't s*it where you eat." kinda applies to this one. 

And yeah, that exhaust port design is weird, to say the least.



jeb said:


> The resurrecting of this thread brings up some questions to mind:
> 
> 1. Why the plastic storage box (other than low cost)? Why not metal studs and corrugated sheet goods like you have on metal garages, etc? Seems like the plastic is a potential heat issue with exhaust, etc...espeically if you have a malfunction with your exhaust fan.
> 
> 2. Moisture / condensation issues for storage. How is it in the plastic boxes? I always worry about storing my genset in those all the trapped moisture. How do you mitigate that?


1. Those popular Suncast sheds aren't available where I live so I would have to custom-build one made of marine board and cement board (for the section around the engine and exhaust). The shed is in a secured and covered area out on my 2nd floor balcony. Nothing but the hand of God would be able to move it.

2. We have tropical climate all-year round (Florida-weather, as some like to call it), and I am nowhere near the coast. Relative humidity does jump quite a bit depending on whether the sun is out or it's drizzling. Condensation is quite rare and it only happens a couple of months in a year (typically January-February). Anyway, the shed obviously isn't going to be airtight so it shouldn't trap any moisture.



iowagold said:


> i would remove the muffler from the gen set and make a flange pipe for the engine for an external to the gen set muffler. and might even retrofit a honda eu7000is muffler! you would need a fan to cool the muffler. but the noise is way down from any thing else out there right now. and a gen stack exhaust vent up in the air.
> 
> and if you go the shed way i prefer concrete and steel for a gen shack... you can set it up as a faraday cage and bunker shed.. in our area of the country we get winds over 100 mph in storms. so ultra heavy duty for me is the way to go.


This was going to be plan B... straight pipe with a flange on both sides protruding outside the shed, where the muffler would then be. I'll probably have to use a short flex pipe to decouple the engine vibration. Though, I'm not keen on leaving the muffler exposed outside.

This is the shed design I'm working on. Nothing yet set in stone and those measurements will change as it hasn't taken into account the materials' thickness and whether I'm going to build it single or double-walled. All that will be up to me and the contractor to finalize. As I mentioned above, the Shed isn't directly exposed to the sun or rain, though some spray from the rain is expected when it's windy enough.

The guy is there for scale.. lol


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## iowagold (Jan 22, 2020)

just keep in mind tropical.
so bugs , rats, snakes, spiders.
all things that like to hide.

use good filter and screen material on the intakes and screens on the exhaust air.

and over build for the heat and structure.


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## OrlyP (Oct 19, 2021)

^ Agreed. There will be screens or vent covers where air needs to pass through.


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## tabora (Sep 6, 2018)

jeb said:


> 1. Why the plastic storage box (other than low cost)? Why not metal studs and corrugated sheet goods like you have on metal garages, etc?



Low cost = $167 for the BMS2500 delivered
Rapid build = three-ish hours including inlet/outlet shutter installation
Nice appearance
Maintenance-free
History of successful builds by others



jeb said:


> Seems like the plastic is a potential heat issue with exhaust, etc...espeically if you have a malfunction with your exhaust fan.


Hence the thermal monitor and alarm. I have a thermal remote monitor mounted top center on rear wall, and a second one mounted outside on the propane tank. The internal alarm is set at 80F and has never gone off in 4 years of operation (about 65 running hours so far).










jeb said:


> 2. Moisture / condensation issues for storage. How is it in the plastic boxes? I always worry about storing my genset in those all the trapped moisture. How do you mitigate that?


No issues for 4 years for this box and for over 20 years with the plastic truck box I used for my PowerMate PM1800 at our island cottage. They are far from air tight, by design. I ran the PM0126000 for about 5 hours during our Nor'Easter today; started right up... Everything in the box still looks brand new.


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## drmerdp (Apr 10, 2018)

On my old setup with a champion 7000 watt generator I built an exhaust system with a muffler and heat wrap and had it exit directly outside the enclosure. The main motivation was the exhaust exited out the back instead of the side. It did keep some excess heat out of the enclosure which was a perk.

I also added a thermal switch to the low oil circuit which grounds out the ignition coil to shut down the unit if enclosure temps got out of hand.


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## ddbama (Aug 3, 2021)

Can you provide additional details on the exhaust / fans used with this setup along with other materials other than the shed you used? Is there an old post where you have this detailed? 



tabora said:


> And the generator make/model number would be???
> 
> That said, a shed needs lots of airflow for the heat, so all you have to do is point the exhaust directly at the exhaust fan and it will be carried out with the airflow.
> View attachment 10312
> ...


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## tabora (Sep 6, 2018)

ddbama said:


> Can you provide additional details on the exhaust / fans used with this setup along with other materials other than the shed you used? Is there an old post where you have this detailed?











Generator shed challenges?


Hi Folks, For years, I've just garaged my portable 15KW generator and wheeled it outside when needed. This of course keeps the generator in a dry, insulated environment. I really need to get the space back in the garage...so contemplating pouring a concrete pad and either building a cover...




www.powerequipmentforum.com












Eu7000 tri-fuel kit Gasoline Propane and Natural Gas


Hey folks. I haven’t been active in a while... first baby, house and home stuff etc... But I’m looking to get back on that horse. I recently purchased an eu7000 and have been planning a generator shed 2.0 build. First and foremost a tri-fuel kit has been the make or break point for this...




www.powerequipmentforum.com












Generator Running Cover


I've had my generator for a number of years but haven't yet worked out running it during a storm. Are there any reasons why I couldn't run it under a table covered with tarp, securing everything together with bunjees? Another option is to run it inside my shed (8x12) that has (4) 18"x24"...




www.powerequipmentforum.com


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