Onan Resonator

Wondering if any of you have first hand experience with an Onan Resonator

Here's a video
https://www.youtube.com/watch?v=gQboSPqKtfE

The video makes it seem like a significant reduction in "noise", but I know not to believe the microphone....

I did a quick search here for old threads and came up blank..... but I'm pretty sure I've seen them mentioned before

I find the Onan a bit louder than I'd like.  It's a typical class C installation.

So I'm wondering what the perceived benefit is from one of these.... not so much the dB number, but how well you think it tamed the grating noise....

bump

I am not sure but that resonator did change the SOUND of the genny exhaust but noise level? Nah not by much, if any. With the resonator, I thought the sound was a little deeper in tone, maybe masked some mechanical sounds somewhat and thus was a bit easier to tolerate but I am not sure I would like to listen to it for hours because of that.

I don't think it did much. I'd rather buy a different muffler all together, than waist money on that. My generac is a lot quieter than that with just a muffler and it's 7000 watt. Some of those direct drive generators have harmonics noise and no muffler can quiet that. I've also noticed that most onans are just stuck in a bay under the coach, not enclosed. They are much more noisy and the do get nasty. My generator is completely enclosed on the sides. The only opening is in the bottom where it draws in and blows out the hot air. 

reviving my old thread...
I must have missed the two replies to this.

I've had this rambling around in the back of my mind a while now.  Stumbled across something a few days ago that brought it back to the front of my mind.... so I ordered one.
Just back from doing a quick trial, slipping it onto the tailpipe to compare with and without.

it's a little interesting...and disapointing.
Certainly not a "big WOW" change.... I suppose not really worth the money as 92GA suggested

measuring the dB using a phone app, not that the numbers mean anything i know, but as a comparative tool
it was an almost an immeasurable change... perhaps a 1dB INCREASE with the resonator.

interior
with an ambient level inside indicating around 22 dB
the genny running under no load indicates around 58 or 59 dB
with the AC on, it indicated approx 62-65 dB

Outside
things were a little bit more noticeable to my ear.  I'd say it smoothed out the sound ever so slightly.... almost a negligible affect.  made it sound a little more trumpet like I would say
with an ambient level measured around 35 (traffic about 150 yards or so away)
I checked at 10 paces away
straight out looking into the pipe
and off 90 degrees from the pipe
measured approx 63 dB both places with and without the resonator
but I did notice the recorded trace was smoother with the resonator

then I took a video on my phone, just to see if reproducing it I could notice anything different.
back at the computer, I can't tell a blip of a difference looking into the pipe
and not much off to he side.... again just a touch smoother is all really....

I guess I'll go ahead and install it.  Won't be that hard and wouldn't feel right about returning it knowing that I did operate with it a few minutes.... it does smooth things out a bit

I'm actually curious now, what affect if any sliding a secondary muffler over the tailpipe might have.  If I ever come across one of a similar size cheap or free I might give it a try just for kicks....

blw2 said:

I'm actually curious now, what affect if any sliding a secondary muffler over the tailpipe might have.  If I ever come across one of a similar size cheap or free I might give it a try just for kicks....

Click to expand...

Years ago I made the following mods to quiet an Onan 4KW in a class C.

First I took it to a muffler shop. Had them cutoff the tailpipe after the muffler and attach a 180 bend. Then increased pipe size to standard car diameter and added a flat, baffled muffler (was for a Ford Falcon if I recall but I was just looking for a large baffled muffler with good airflow that would fit). Added several muffler hangers so none of this added weight to the genset. Dropped noise very noticeably.

Since I was now getting virtually no exhaust noise I could tell the remaining noise was engine noise through the door vent (this Tioga had a genset compartment with a screened door for cooling air entry - you could look through the screen and see the genset - noise came right out). I measured surface area of vent screening and built a box to cover the vent, so the air had to go up and make a 90 degree turn before entering compartment. Air entry still had about the same area. I then lined the inside surface of the deflector with thin foam glued to the surface, so that noise coming out was somewhat absorbed.

Having now gotten much quieter the last of the noise was that reflecting off the ground below the genset. I made a removable panel that could hang like a skirt below the genset, hung to within about 2" of the ground.

I never measured with a DB meter but the combination of all the above made a dramatic improvement. I used to take this rig to the air races every year, and sitting at the campfire we could hear a rig 4 rigs down with a genset running, and yet couldn't hear mine just 2 rigs down.

Don't think any of this improved interior noise but that wasn't my concern.