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Author Topic: Use EMT conduit for gen exhaust?  (Read 450 times)

skeeter_ca

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Use EMT conduit for gen exhaust?
« on: October 22, 2017, 02:31:27 PM »
Is it ok to use EMT conduit for a generator exhaust extension. They have the correct sizes I need at a low price. It is a galvanized mild steel with .060 wall thickness. I will do a small amount of MIG welding on it. I am designing a DIY Gentrui system.

skeeter

jubileee

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Re: Use EMT conduit for gen exhaust?
« Reply #1 on: October 22, 2017, 02:39:54 PM »
I think it would be absolutely perfect for that application.

Jeff

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Re: Use EMT conduit for gen exhaust?
« Reply #2 on: October 22, 2017, 03:06:54 PM »
The backpressure on the engine is a function of exhaust pipe length and diameter.  A simple way to avoid that and to cool off the extension is to use a larger diameter extension and install the generator pipe blowing  into the larger pipe for a  couple of inches. This removes the back pressure and sucks in outside air to help cool the pipe.


Here  is a photo.

Gary RV_Wizard

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Re: Use EMT conduit for gen exhaust?
« Reply #3 on: October 22, 2017, 04:01:44 PM »
EMT should work OK. The gases aren't under much pressure or even very hot bu the time they reach the side of the coach.

Jeff's suggestion of running the genset pipe into a larger one, with several inches of overlap, is an excellent one. I used a 24" elbow about 1.25x the diameter of the exhaust pipe, and then the upward pointing end of that into a 3" PVC pipe, withe plenty of open space. That sucked cooler air in the bottom of the OVC as the warm exhaust rose to the roof. The PVC hardly even gets warm to the touch. Schedule 40 or 60 PVC is rated for 140 F.
Gary
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Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL

NY_Dutch

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Re: Use EMT conduit for gen exhaust?
« Reply #4 on: October 22, 2017, 06:20:18 PM »
Yep, and of course the "venturi effect" of the smaller pipe sucking cool air into the larger riser pipe is exactly what the "Genturi" does, and hence the name... :)
Dutch
2001 GBM Landau 34' Class A
F53 Chassis, Triton V10, TST TPMS
2011 Toyota RAV4 4WD/Remco pump
ReadyBrute Elite tow bar/Blue Ox base plate

Old_Crow

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Re: Use EMT conduit for gen exhaust?
« Reply #5 on: October 23, 2017, 05:28:25 AM »
Wow, the PO of my coach left the Gen-turi adapter on the generator exhaust pipe.  Looks like a trip to the hardware store is in order.
Wally Crow
Retired 30 year ASE Master Auto Tech
Y2K Bounder 36S F53
'03 Jeep Wrangler Sahara

Isaac-1

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Re: Use EMT conduit for gen exhaust?
« Reply #6 on: October 23, 2017, 07:49:29 AM »
I thought about doing the same, then ended up buying a new GenTuri on ebay for about $110 (they were about $120 on Amazon, which I tried first, but ended up canceling the order after it still had not shipped in 9 days), which is cheap enough that I doubt I could save enough rolling my own for it to be worth it.
2002 Safari Trek 2830

NY_Dutch

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Re: Use EMT conduit for gen exhaust?
« Reply #7 on: October 23, 2017, 08:12:13 AM »
I thought about doing the same, then ended up buying a new GenTuri on ebay for about $110 (they were about $120 on Amazon, which I tried first, but ended up canceling the order after it still had not shipped in 9 days), which is cheap enough that I doubt I could save enough rolling my own for it to be worth it.

Yep, I was all set to roll my own, but before I found the requisite "roundtoit", I picked the real thing up at an RV dealership bank auction for $56. I don't think I could have bought the parts and invested the labor for much less than that.
Dutch
2001 GBM Landau 34' Class A
F53 Chassis, Triton V10, TST TPMS
2011 Toyota RAV4 4WD/Remco pump
ReadyBrute Elite tow bar/Blue Ox base plate

Charlie 5320

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Re: Use EMT conduit for gen exhaust?
« Reply #8 on: October 23, 2017, 09:35:46 AM »
I also bought my GenTuri  on Ebay for $110.00 shipped. What will you save buying all the parts necessary to build one at home? Not worth the headache to me. I didn't want to drill holes in my coach for the brackets, so I bought 2 suction cups [also on Ebay] for less than 10 bucks. They were for a Garmin that had the knob and stands away from the coach when installed. They work great. Can't hardly pull them off until you release them. I'm a do it yourself guy, but just didn't make any sense to me to try and make one for what they cost, and you have the storage bag to boot.
2003 National Dolphin 5320
496  8.1  Workhorse

98 Damon Daybreak 3130
GM Vortech 454  4L80E
SOLD

QZ

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Re: Use EMT conduit for gen exhaust?
« Reply #9 on: October 23, 2017, 09:54:47 AM »
Number one issue when building one is providing appropriate amount of air blend and not creating back pressure on genny. I have worked on a couple generators where people fasten a long exhaust pipe on them and started melting things. It helped with the noise but they couldn't get rid of the heat.
« Last Edit: October 23, 2017, 10:45:19 AM by QZ »

John From Detroit

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Re: Use EMT conduit for gen exhaust?
« Reply #10 on: October 23, 2017, 10:31:40 AM »
The Venturi effect is why the GEN-Turi is called :Turi"

The big black pipe gets so hot I once stood there for like 5 minutes with my hand wrapped around it to demonstrate.

ONLY once Have I ever needed gloves to handle it... SUNLIGHT was the culprit. the generator had long since shut down.
Nothing adds excitement like something that is none of your business
My Home is where I park it.

skeeter_ca

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Re: Use EMT conduit for gen exhaust?
« Reply #11 on: October 23, 2017, 03:02:39 PM »
I plan on having mine permanently mounted on the back side of the 5'er where the genny is permanently mounted on a cargo carrier. The genny exhaust outlet is 3/4". I am starting with a 1" adapter which would then go into a 1 1/2" flex exhaust pipe about 4 ft long. That would angle up into a 3" diameter double wall flume ducting with the venturi design to go about a foot above the roof line. Anyone see any problems with this setup.

skeeter

john owens

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Re: Use EMT conduit for gen exhaust?
« Reply #12 on: October 23, 2017, 03:50:38 PM »
I built one for my 85 LazyDaze. Genset sits right behind the drivers door. I found a proper diameter fitting radiator hose and cut it down a bit to give me the proper angel. Than installed 1 inch copper pipe running vertical above roof line with a 45 degree fitting on top. Looked cool and was very quiet. Used conduit brackets that screwed into existing holes along the seam going up. Looked cool in the winter puffing like a locomotive...
2011 Winnebago 37F Class A  2012 Unlimited JK 2001 HD roadking  1964 Manx 1641cc buggy 1985 22'Lazy Daze Class C 2007 Chaparrel 26' deck boat..Thats all folks!!

QZ

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Re: Use EMT conduit for gen exhaust?
« Reply #13 on: October 23, 2017, 04:58:32 PM »
I built one for my 85 LazyDaze. Genset sits right behind the drivers door. I found a proper diameter fitting radiator hose and cut it down a bit to give me the proper angel. Than installed 1 inch copper pipe running vertical above roof line with a 45 degree fitting on top. Looked cool and was very quiet. Used conduit brackets that screwed into existing holes along the seam going up. Looked cool in the winter puffing like a locomotive...

Copper? Now that is class! :) I like it.  Steampunkish.

 

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