Changes to generator exhaust

[OKPETE]

Will install resonator from Onan with super trapp 5s spark a restor muffler. The resonator changes tone of exhaust for the better. Still not sure about super trapp will finish con figuration this afternoon.. The purpose of this post is to suggest that anyone doing this modification check with supper trapp because getting info from Jacks Small ENgine is difficult.. My thoughts are that using the resonator from suppertrapp would be the way to go instead of Onan resonator. That said I ordered the resonator from Onan for 36.00 dollars. The suppertrapp arrives today and will be interesting retrofitting to space on Pleasureway Rb plateau. The biggest problem is generator noise not exhaust noise. Will soundproof top and call the effort good . After completion will post results but have not taken any sound level readings to verify results.
Pete

[Arizona_Kid]

Send Handbasket a PM. He did a setup using a spring as a hanger.

[EsoxLucius]

Thanks for the heads up on the Super Trapp. Where does one get the string hanger? Or can one just make sure a regular exhaust hanger attaches to the generator and not the vehicle frame.

[Arizona_Kid]

Most of the Class B generators are underneath the rear end, not many in a compartment.

Oops, I see you have a Class C. If you want my opinion on the Supertrapp, I don't think you will notice enough of a difference to justify the cost. I seldom used mine.

[EsoxLucius]

One of my next projects is the Onan resonator, clamp on 5S Super Trapp, and insulating the compartment with Low-E on an Onan 3600 LP.

[Arizona_Kid]

If it was reduced by 10+ decibels the noise would be reduced 90%, or more. I could see a couple decibels, but hard to imagine 10+ decibel reduction. I would be interested in reading your references, or how you did the measurements.
I just don't see how that could be done to an Onan 2800, and still allow enough air for it to breath, and stay cool.
I do agree, more insulation, and a spring hanger like Handbasket has done, along with the Resonator will make quite a difference.

This post by Travelin Bill.

Also, FYI - the dB is a ratio of the percentage of energy (noise) change and the scale is a logrithimic scale, not linear. The percentage is the percent of original energy (noise) remaining, not the percentage of energy (noise) lost.
0dB = 100%
1dB = 79.4%
2dB = 63.1%
3dB = 50.1%
4dB = 39.8%
5dB = 31.6%
6dB = 25.1%
7dB = 20.0%
8dB = 15.8%
9dB = 12.6%
10dB = 10%

If I change the noise level by 1dB I have reduced it by 20.6% with 79.4% of the noise remaining or increased it by 20.6% to 120.6% of it's original level. If I change the noise level by 2dB I have reduced it by 36.9% with 63.1% remaining or increased it by 136.9%. If I reduce the noise level by 3dB I have reduced it by 1/2. If I increase the noise level by 3dB I have doubled it. etc.

* This post was edited 04/03/08 08:22am by Travelin' Bill *

[mlts22]

Another thing I often notice about Onan generators. A lot of RV makers mount them very poorly. Ideally, there should be mounted with rubber shock/vibration mounts, the exhaust also should be mounted to minimize vibrations, as well as the fuel hoses and wires. The area between the top of the generator and the van should have some type of insulation, be it Dynamat insulation that is resistant to heat and such, or another acoustic format.

A good installation can take 10+ decibels off the noise of a generator with ease. I've seen this done with some of the larger Onans which were running quieter than my 3000 watt inverter Yamaha.

[Arizona_Kid]

Here is a Archive link to Rodger's posts about the Resonator, and Super Trapp.
His web site is no longer, so no photos.
I believe you should use the Supper Trapp 3 for the Onan 2800. Also, make sure you use the correct number of discs for the 2800, or you could have too much back pressure.

http://forums.woodalls.com/index.cfm/fuseaction/search/parms/sw%7Bsuper%20trapp%7D%7Ckm%7Bexact%7D%7...

SuperTrapp 3S Series Spark Arrestor Small Engine Mufflers
https://www.pegasusautoracing.com/group.asp?GroupID=SUPERTRAPP3S

The resonator will help quite a bit, but the tail pipe will need to come off, and be cut, and the resonator welded in. Make sure when it is welded the curve of the tail pipe stays in the same proximity as before it was cut and welded.
Used with the resonator, the Supertrapp will help but not a whole lot, by this point the engine is making most of the noise.

[mlts22]

Why not both? The Onan resonator is definitely covered/warranted by the generator maker.

The Supertrapp 5s can void the warranty, and might prevent one from using a Gen-Turi, but just reading up on threads about it, a lot of people are happy with the resonator/Supertrapp 5S or 3S (for smaller generators).

[BudJ]

"My thoughts are that using the resonator from suppertrapp would be the way to go instead of Onan resonator."

Nope, the resonator makes noticeably more difference compared to the supertrapp. I used and compared both.

Bud

OKPETE wrote:
Will install resonator from Onan with super trapp 5s spark a restor muffler. The resonator changes tone of exhaust for the better. Still not sure about super trapp will finish con figuration this afternoon.. The purpose of this post is to suggest that anyone doing this modification check with supper trapp because getting info from Jacks Small ENgine is difficult.. My thoughts are that using the resonator from suppertrapp would be the way to go instead of Onan resonator. That said I ordered the resonator from Onan for 36.00 dollars. The suppertrapp arrives today and will be interesting retrofitting to space on Pleasureway Rb plateau. The biggest problem is generator noise not exhaust noise. Will soundproof top and call the effort good . After completion will post results but have not taken any sound level readings to verify results.
Pete