Generator exhaust noise

[Jeff64]

Originally Posted by russ240

Thanks for finding a great option for us! I just went to the website but there seem to be lots of variations. Can you provide the part numbers you ordered?

Thanks again!

I ordered the clamp on 1 1/2" diameter 5S muffler part # 5S1500H it will come with 3 diffuser rings, you only need one so you don't need to order those. I also ordered the 6" resonator part # 5S5536 It fits together very easily and will slide tightly over the exhisting pipe which you will need to shorten some and comes with a clamp.

I have used the generator and air a little with no problems, if back pressure becomes a problem with this type mufffler one could add another diffuser ring, however this muffler is rated for a much higher horse power engine than the generator . I know there are those who have concerns regarding the warranty, I suppose you could loosen the two nuts and slip it off before service. Personally I am not concerned about it, to me it was annoying enough that I wouldn't use the generator and now I am much happier with it.

[73shark]

Let us know how the air conditioner works on a 95 degree plus day when the current draw is at maximum for the generator.

[Boxster1971]

This Supertrapp muffler looks like the perfect solution to exhaust noise. It's another product made in Ohio and I've attached a copy of the brochure. It is available from many sources.

[herrick51]

Originally Posted by Jeff64

I ordered the clamp on 1 1/2" diameter 5S muffler part # 5S1500H it will come with 3 diffuser rings, you only need one so you don't need to order those. I also ordered the 6" resonator part # 5S5536 It fits together very easily and will slide tightly over the exhisting pipe which you will need to shorten some and comes with a clamp.

I have used the generator and air a little with no problems, if back pressure becomes a problem with this type mufffler one could add another diffuser ring, however this muffler is rated for a much higher horse power engine than the generator . I know there are those who have concerns regarding the warranty, I suppose you could loosen the two nuts and slip it off before service. Personally I am not concerned about it, to me it was annoying enough that I wouldn't use the generator and now I am much happier with it.

Hello,
I've done the same as you except used onan resonator with suppertrapp. However,the tech at suppertrapp recommended 2 diffuser plates. I did not measure noise level but it seems to lower noise level and takes out the lawn over sound. Now you get hear how noisy the generator can be. I'm going to insulate the top and call it quieter. Pleasureway does a nice job of building brackets to mount onan but seems it would be difficult to add vibration eliminator s at mounting pts. Overall glad I made changes. The car muffler is author good option
Pete

[Jeff64]

Originally Posted by herrick51

Hello,
I've done the same as you except used onan resonator with suppertrapp. However,the tech at suppertrapp recommended 2 diffuser plates. I did not measure noise level but it seems to lower noise level and takes out the lawn over sound. Now you get hear how noisy the generator can be. I'm going to insulate the top and call it quieter. Pleasureway does a nice job of building brackets to mount onan but seems it would be difficult to add vibration eliminator s at mounting pts. Overall glad I made changes. The car muffler is author good option
Pete

Yes you are correct these things arent quiet even with little or no exhaust noise, I think the liquid cooled generators are much quieter. It's interesting that they told you to use two diffusers, that is determined by the horse power. Can anyone tell me how many horse power these generators are?

Jeff

[Boxster1971]

Originally Posted by Jeff64

Yes you are correct these things arent quiet even with little or no exhaust noise, I think the liquid cooled generators are much quieter. It's interesting that they told you to use two diffusers, that is determined by the horse power. Can anyone tell me how many horse power these generators are?

Jeff

From the Cummins Onan Spec Sheet:
Engine details
Model: EX 21
Design: 4-cycle, single cylinder, OHC
Displacement: 13.2 in3 (217 cm3)
Compression ratio: 8.5:1
Power: 7.0 bhp (max) at 3600 r/min
Cooling: Pressurized air

[joemikeb]

Originally Posted by Jeff64

I ordered the clamp on 1 1/2" diameter 5S muffler part # 5S1500H it will come with 3 diffuser rings, you only need one so you don't need to order those. I also ordered the 6" resonator part # 5S5536 It fits together very easily and will slide tightly over the exhisting pipe which you will need to shorten some and comes with a clamp.

Jeff, I am curious why you opted for the 5S5100 instead of the smaller diameter 3S5100? With the smaller diameter 3S you would, of course, have to use a couple of additional diffuser rings but the smaller diameter would appear to be a better fit. Certainly given the generator exhaust location in my 2013 Interstate. Would you anticipate a significant difference in sound attenuation between the two?

[Jeff64]

Originally Posted by joemikeb

Jeff, I am curious why you opted for the 5S5100 instead of the smaller diameter 3S5100? With the smaller diameter 3S you would, of course, have to use a couple of additional diffuser rings but the smaller diameter would appear to be a better fit. Certainly given the generator exhaust location in my 2013 Interstate. Would you anticipate a significant difference in sound attenuation between the two?

I noticed on the website that they said the 5s was the most quiet, that was the only reason for choosing it.
I agree the 3s would be a better fit and may not require a hanger support. I'm not sure if or what size resonator you can get with the 3s but the website makes it clear that you must use the resonator to achieve the best results for sound control.
I noticed another member used a cummins resonator and a super trapp muffler and I assume with the resonator on the super trapp as well. That could be a good option with the 3s. I was a little concerned with the size of the 5s when I got it but all said and done it fits quite nicely, it has no clearance issues and it is not visible unless you are on your hands and knees.

[MILATV]

Local muffler shop - had this laying around for a Cummings diesel

[jdalrymple]

I don't have an Intertate, but I have worked with generators a bit.

Looking at the specs posted earlier, the real problem is the RPM at which these units operate.

It is very difficult to make anything turning 60 times a second quiet.

The lower RPMs of inverter type gensets is what keeps them quieter.


Regards,

JD

[Skater]

Originally Posted by jdalrymple

Looking at the specs posted earlier, the real problem is the RPM at which these units operate.

It is very difficult to make anything turning 60 times a second quiet.

The lower RPMs of inverter type gensets is what keeps them quieter.

That makes a lot of sense. Someone claimed that most of the noise is exhaust noise, and I remember hearing the exhaust noise from mine, too, but it seemed like at least half of the noise from mine was engine noise.

[73shark]

And it's also, I believe, an air-cooled engine which are inherently noisy.

[joemikeb]

Originally Posted by Jeff64

I can finally report back on my solution for what I consider to be noisy generator exhaust. I ordered the cummins resonator and I also ordered the 5S Super trapp muffler with 6" resonator from Jacks small engine, I tried both and the Super trapp was the winner hands down, there is almost no exhaust noise just the noise of the engine itself. I'm attaching a picture. I intend to add a hanger at the muffler attach point and omit the original factory hanger.

My SuperTrapp 5S is "in the Mail". This looks like a relatively simple and cheap solution to an annoying problem.

[bugsbunny]

I don't have an Interstate yet, but could you tell me where the generator is located?

Thank-you,
Bugs

[73shark]

It is located behind the rear axle in front of the spare tire.

[joemikeb]

Originally Posted by bugsbunny

I don't have an Interstate yet, but could you tell me where the generator is located?

Thank-you,
Bugs

transversely mounted underneath the vehicle on the centerline and immediately behind of the rear axle.

[bugsbunny]

Is any portion of the generator mounted inside the cabin part of the motorhome?

I looked at a 2005 Roadtrek RS Adventerous last week. There was a box that had some portion of the generator under the bed inside the cabin covered with wood.

How is the generator noise inside the cabin when in the back with the TV on and the AC is running?

Thanks,
Bugs

[73shark]

The Airstream generator is mounted completely below the floor and suspended from the chassis.

[MILATV]

I can tell you the generator is the least of your worries when the AC is running - that thing is LOUD! My Bathroom becomes a phone booth when the AC is running The AC is loud enough to make it hard to carry on a normal conversation on the telephone.

Tv in rear bed was loud enough and neither the generator or the AC made it difficult to watch TV.

The generator noise isn't unbearable in the van but it is louder than I would like. Even with the muffler I installed (which helped the outside noise; more of a change in frequency than reduced amplitude I think) but glad I did it.

[Boxster1971]

Originally Posted by MILATV

I can tell you the generator is the least of your worries when the AC is running - that thing is LOUD! My Bathroom becomes a phone booth when the AC is running The AC is loud enough to make it hard to carry on a normal conversation on the telephone.
...

I wear earplugs at night if I have to run the AC.