I manufacture fiber glass packed (sound absorbing) mufflers for cars from 12-40" long. I've found that silencing gains are minimal after 40" in length. There are 3 ways to silence an engine or in your case of a heater, sound absorption, sound reflection, or restriction. Or any combination of the three. Of course you don't want to restrict a heater. I've also machined 4140 dies to bend, reduce, and swedge tubing to make exhaust pipes out of quality material for these heaters so two pipes can be joined by slip fit and clamp. Thanks for the video. Jerry in Montana

I made my own silencer with an old stainless vac flask. I drilled 12mm right through the bottom two layers and silver brazed a patch on the outside hole. I then drilled about a dozen 4mm holes at random in the outer skin and made a connector which I silver brazed in the top. It’s very quiet and the price was just right

We asked, you delivered. Many thanks, most interesting result.

That's the silencers covered. .....now on to the loudeners. ....

Thank you for doing the test so we do not have to. This is good information not found elsewhere.

cheap silencer: take a metal paint can drill hole in lid for exhaust in. Take can drill small holes in bottom so area of small holes equal exhaust size. Fill can with corse stainless pot scrubbers. Install lid and install on exhaust. Added benifit, you can easily replace or clean silencer medium

You can tell someone was given an original Webasto exhaust in China and were told to "make this, but cheap"

My way of thinking is that a silencer needs two things. Gas expansion and slower airflow. I reckon a steel box lined with wadding and an internal baffle plate would deaden the sound and reduce the venturi effect at the outlet. The gas is creating the noise at the outlet on all of them as airflow in = airflow out. A box that allowed gas expansion and therefore a slower exit speed (bigger hole out than in) would do the trick. A car exhaust needs back pressure so a straight through exhaust can reduce performance without fuelling mods, whereas the heater just needs somewhere for unrestricted burnt gas to go.

I come for the "hellooooo" and stay for the interesting content. Thank you sir 👍

Adding an additional silencer on the burner INTAKE air connection will make the BIGGEST improvement on a campervan installation. Sound waves from the combustion noise travel upstream too!

I bought a cheapo ebay pit bike exhaust 12/13 quid. Has done an amazing job, surprised me just how good it was.

three silencers....I love this guy. There are some garden tools that could do with a proper silencing :-)

Excellent video. Thanks for taking the time to film and share. Here's an idea for you to try? Big issue with CamperVan wive's. 💡idea alert... for people with hair: Scenario: Not enough battery power in the camper for wife's hair dryer - How do YOU cope? We have a CDH which blows warm air out of a 100mm vent. If I got a vacuum hose with a crevice attachment at one end, and a 100mm funnel reduced to fit the other end of the hose - then temporarily secure it over the heater vent - in theory, this should blow concentrated warm air out of my crevice enough to blow dry my wife's hair? MACK and Maggie, Huddersfield

I have no idea how I ended up here, but I'm gonna go have a poke around, sounds like I might fine something interesting on this channel.

Webasto make a marine silencer and we HAVE TO use them in narrowboats. They are NOT like the one you have that has a drip hole on the bottom for water to drip out. This also lets out exhaust gases so could kill you if you were on a boat. You can crimp and weld the hole shut but a boat safety inspection may pick this up and fail you. Back pressure can be a problem with lots of boxes fitted I have found. it also depends how close or far you fit the box on the pipe work. Love the video clips would be good to see more trouble shooting on Webasto heaters....

my silncer is 2 6x12 aluminum boxes welded together with heat syncs and a fan with then a 7/8 tube running out the wall. really quite and gets extra heat off the exhaust to use as extra heating for the garage. now ideally i would have some copper tube and water to get more heat out of it.( to maximize the heat you can use the exhaust temp going outside should be room temp but good luck with that)

I run my 5000watt Colman power mate through a muffler of an old dodge Dakota 👍🏻🇨🇦

Generally speaking, they are barely going to help chaining the same style. Your best bet it to chain 3 DIFFERENT silencers, as they work on different frequencies of noise, depending on the internal configuration.

Ohh my god I bought a second to do this and never got round to it!. Thanks for the vid!

I'd guess the big silencer would be even more effective when heard from a distance, it better attenuates the low frequencies. Interesting.

Sounds like the small resonators let the low fq pass, the giant unit lets the high fq pass. Put them in series?

Great comparison. Thanks from New Zealand

What about restriction introduced by each? Maybe tee in a manometer and see the pressure difference where the exhaust exits the shed? Then it can be determined if you may need to tweak fuelling

i think this was the nices hello an the best greeting ive ever heard , i sub for this

Cheers mate. Can't wait to unbox my chinese heater to see how loud it is... no muffler was provided...

If you a product called safe and sound insulation Batts. Made you own baffled box. With multiple exhaust holes the sound will be incredibly low. This insulation is fire proof and water proof to a point.

Loved the video thank you. As of January 2022 in USA, Ebay Webasto muffler $50 usd = gbp $38

It would be interesting if you could figure out how much back pressure each of these silencers create, the Webasto one probably creates quite a bit of it due to the zigzag in the tube. The scooter one may therefore be superior (if you have the space) as it looks like it is a straight tube.

I run with two original webasto silencers. it excellent.

You should do a review on 12v ovens?

Interesting, ty! I wonder how much if any exhaust flow reduction occurs and if it impacts performance of the system. Even if it did, it might not be much or even concerning for some people. I heard the noise of a diesel heater can be pretty loud in many cases. They are an excellent source of cheap heat in many instances.

How did I get here watching videos about diesel silencers? Thumbs up though.

Great, 'Real World' demonstration! Subbed !

Good fun to watch you, much appreciated!

I've found the most noise comes from the air intake, I've adapted mine and it certainly quiter now

Always have fun watching creativity.

Is it possible to make the silencer into a heat exchange for hot water? Would be great to use all that wasted heat.

You do not want to inhibit the exhaust gases beyond the original design. If any thing get an old car muffler a small one or cycle muffler go larger don't restrict the exhaust. I think a heat exchanger would be a nice addition and capture the waste heat of around 3 to 4 hundred degrees F.

Hellooooo from America , thank you for doing this test anyway you can test the marine mufflers

I read using spiral pipe rather than the ribed pipe provided is quieter without a silencer, than a ribed with a silencer

I mean it's not really a muffler, two slices of steel with spring inside. I run heat exchanger instead and that not only eliminates noise but actually helps recover ar least 50% of exhaust heat.

Thanks once again for your time and effort David. 💪💪💪 Keep at it mate. ✌️🙏✌️

you do know you can install a DB Meter on your smartphone right .. :) Love your videos.. you are the best

Well done mate ! 🙂👍🦘

Hi David great videos. I’ve heard that you shouldn’t exceed a 270 degree angle on the exhaust outlet and doing research those cheep muffler have a v in side with two of them plus the 90 degree coming out of the bottom of the unit you might mess the performance of the diesel heater up there are two sorts of cheaper muffler one like yours and one that is a straight through one also the straight through one is a lot quieter then the v shape hope this helps

Hmm, I would suspect that adding silencers will start to really restrict the exhaust flow. Interesting experiment :)

What you do is run a long pipe over the fence to the neighbour's house...

Yeah I played it back a couple of times and have to agree with your conclusion, as far as I can tell via mic your end and speakers my end 😉

Inrested of opening those silencers and look what inside?

excellent demonstration Thanks Ya

from what i could hear of it i could say the biggest difference was having a muffler on it or not having a muffler on it.. but the generator muffler did seem it may have made a bit off difference over the others

fantastic demonstration thank you.

Obviously the black muffler is the best ... What is it and where do I get one ?

If you want quiet fit the sealed eberspacher marine system

Cooper fittings make sound louder back in the hay days we fitted copper sleeve pieces into our exhaust pipes on our car exhaust it when got hot the heat made the copper crackle and the tune out off exuast pipe was louder

good to know when winter comes

Thanks!

I changed the exhaust on one of my trucks and just used the muffler and pipe section of one side. It’s a 2.25” diameter pipe, about 5’ of length plus a generic muffler, the exhaust is much quieter than the fan and see no reason to change it.

I like your vids, god you make me laugh

*hooah* Grazie ! Sei un *Genio!* hooah

Thank you for sharing

Thank you

GOOD MORNING DUDE !

I would get a new universal car muffler / tractor /car/truck 2inch diameter much larger than tiny ones in video and use it for heat recovery inside . Also would paint all mufflers and pipe hi heat black . Lot of wasted heat going out side .Just like building hi performance car exhaust . If you look lots of discontinued mufflers around cheap

The black one was the most quite

Loving the experiments! I might have missed it in the earlier videos, but did you mention where you got the generator silencer from? Thanks.

Thanks, this is what I want to hear.. 👍

The silencer is reducing the noice but it's getting rid of the condenced water vapor too? The silencer produces some drops of water from the bottom?

Just came across your vid . have to say the Vehicle muffler is the quietest . What would a larger bore exaust pipe do ? ( short 25mm from the heater to a 2-3 inch diameter pipe then fitted with a muffler .

Did you consider the back pressure the muffler causes the pump?

Theres literally no restriction in the clones - is the Webasto similar? I would pack some stainless pot scrubber inside but not too tightly but more in centre so exhaust gets pushed around then out other side? Give that a test?

Interesting video! Is the Espar (Eberspaecher) exhaust similar in quality to the Webasto exhaust?

@2:30 did anyone else point at the screen saying "there it is" when he said that he couldn't find the copper bit? Or was it just me?

Can you do 2 tests for me please ? 1. Can you run two controllers connected at the same time ? 2. Can you extend the exhaust and see if anything happens as I’ve heard you must not extend it due to back pressure

don't know why but the 3 clone silencers daisy chained looked so funny .. i wonder about 1 clone at the heater & a 2nd one at the end of the exhaust pipe ( i'm thinking of the 2 stroke bike resonator chamber then silencer set-up )

Interesting. Copper should not be used in exhaust systems of internal combustion engines as it gives off toxic gasses at high temperatures, Shame, because in other respects its the perfect material. Very interesting video!

That's interesting. I thought the biggest one was the loudest. The scooter seemed best

can you try silencing the hot air out as i find the fan noise the loudest

The best thing to do is probably tap into your vehicles exhaust system. At the end of the day it is very hard to get rid of the sound of moving air 🤷🏼‍♂️

Thankge great info

Does lagging the exhaust pipe make any difference to the noise level (or perceived level) ?

I hear the small scooter changes the pitch to a lower octave but the generator can either don't cut the high octave sound or its resonating inside, can you use try the scooter exhaust and then the generator can? Just wondering if its the can that's resonating.. If its not then you have a high cut silencer and then a low cut sound silencer :)

0:00 Hallooow

I use two of the "clones" cheap and cheerful and makes enough of a difference.... Does anyone know if there is some kind of lagging that would effect the volume ?

*My* cheap Chinese heater is run without any muffler and I can honestly say that it is quiet. So, why even have more than one when none works quite well?

Is it better to have muffler at the end OR middle of the exhaust pipe?

You could try the fart cans the kids put on their hondas. See how long before the neighbors complain.

I got no idea what that exhaust? He silenced was from or to what purpose it serves, but more so I'm baffled why this is in my recommendations...

Hello Mr McLuckie do you know roughly how long the exhaust pipe from a diesel heater can be before it starts causing problems with combustion, as the exhausts that come with the heaters seem a bit short, i see ones for sale at 1.2 meters even 2 meters long but am unsure if these would be suitable or to long. Also really enjoy your videos they are Awesome 😁😎

I noticed air bubbles pumping into the heater. It burps and farts some days from the muffler . Any way to fix that? It's a Russian Planar 8DM mode. Thanks

QUESTION ? Can i tap into my main vech. exhaust ( before the muffler ) and run it that way ??? I would drill the hole on a angle so it shoots the exhaust into the direction of the muffler :) Peace and thanks for any advice on this idea :)

Daisy chaining the same kinda silencers is not the best idea. Can you make a test with your original silencer chained to the small regular silencer chained to the Chinese drum silencer?

nice

What about the wabasto and the the 3 clones then the scooter one

I'm confused on what the source is? 5000watt generator? Like reciprocating engine generator or a kerosene burning heater of some kind?

Meant to ask David. Is these connections 25mm copper pipe??? ✌️🙏✌️

has anyone figured out the best way to recoup exhaust heat which still allows the heater to function properly longterm ? I am planning on turning my heater to the side, so the bottom exhaust output is now to the left side this way I can route it into a heater coil from a car, and than route the last few inches of pipe that comes out the heater core, out the window...This will allow me to do this ,without using any 90 degree turns/ unions.

Via your mic, the moped thing done best to my ears, bang for buck. It get rid of the high notes I don't think you can hear. Rather a bass note than hiss. But that care exhaust box was all around the best, but thats custom ish

Just jam a potato into the pipe. Job done.

KZfaq normalizes audio levels. Everything would have similar noise.