Air Spring Isolators for Generator and more noise reduction - 2000 Endeavor

[Ted DuPuis]

This was during an initial test fit when I did a few tac welds before fully welding it all together. A few more bolts and it should be ready to go. I’ll be very curious to see how it does.

[wamcneil]

Nice. Do the air springs raise the generator up higher than its original mounts?

[Ted DuPuis]

Originally Posted by wamcneil

Nice. Do the air springs raise the generator up higher than its original mounts?

It does not. I redid the mounts and lowered them to make room for the springs, so the generator height and overall position is essentially the same as factory.

[Ted DuPuis]

I was able to run the generator for the first time with the air bag mounts. All I can say is "Wow!" what a difference!

I haven't yet done an exhaustive test to include running the generator at max load (such as with both rooftop ACs running). However from my initial start, high idle, running, etc. the vibrations inside the RV are effectively eliminated. The sound both inside and outside is noticeably reduced as well. Not eliminated (and I'll never get it eliminated) but a lot lower than it was.

Overnight I had the bus on its own suspension (instead of on jacks, which it's been for a while as I've been working on various projects). The air leaked out overnight in front and this eventually resulted in the generator airbags deflating and the generator resting on bump stops. I haven't run it in this configuration yet (although I will at some point), obviously it will not be as smooth as with the air springs working. After crawling under the bus I found the nuts on the air lines going to the front air springs were looser than I had expected. I probably didn't tighten them enough when I put the springs on. So I tightened them down some more and we'll see if that resolves the problem.

High end coaches that have this setup for generator isolation also normally have electric air compressors to keep an air supply for this and all the other air-powered devices on the coach. In my case, the only air powered devices are the step cover (normally used while driving) and this, so not much air should be required if the system can stay sealed enough. If not, I may have to add something, but that's a minor nit.

We'll see after the next trip, but I am definitely pleased with this upgrade and how it turned out.

[JNSNWT]

Congratulations on your latest victory

[Ted DuPuis]

Originally Posted by JNSNWT

Congratulations on your latest victory

Thanks!

[Ted DuPuis]

We just got home from an 11-day, 3500 mile trip. On the trip we had probably about 4-5 times where we ran the generator, either overnight or at a campground without hookups.

We continue to be very pleased and impressed with the noise reduction and vibration elimination. The biggest noise reduction is noticed inside the RV, where it's become much harder to tell if the generator is running or not. You hear a bit of the engine noise, but no vibration is felt, and the noise in the RV that's caused from those vibrations making other items shake/rattle is eliminated.

The generator can still be heard from the outside, but it's a lot better than it was. The improvement seems to get greater as the generator goes up in RPM and power output, which is nice since the higher power outputs were especially annoying.

The one flaw I've got with the system at this point is that when I do an air dump on the system (to lower the bus when using the leveling jacks when parking) it seems to dump air going to the pressure regulator, which eventually results in the air springs losing pressure. There are a few ways to potentially address this, but I think the easiest one is probably adding a check valve and a small air tank of some sort to keep enough air to maintain pressure, or else a small compressor. I need to think about this more.

One question I'd gotten somewhere along the line in this was whether I'd considered just using rubber mounts, and I'd figured if I was going to do this, I might as well go all out. However I have run it with the generator air springs empty (0 psi) and the generator resting on the polyurethane bump stops. I can say that there is still a noise reduction and a vibration reduction, and it's significant, but the air springs do still work better.

I still feel like the generator itself is louder than it should be. Sometime this spring I hope to pull it for a full service. I have reason to believe that it's never been pulled in the 23 years and 2500 hours it has on it, which would be way overdue for a belt and likely also hoses as well. But also while in there I want to see if the internal motor mounts are shot, which I expect they are and could contribute to the external noise.

While the generator is out, I'm going to add some sound deadening above it (Dynamat or the like). Above the generator is just a piece of sheet metal that serves as a firewall to the cabin. However it rattles and tin cans something awful tapping it. With the generator out I should be able to clean it up well and get it to where I can put on some sound deadening which ought to help the situation.

After that, I have some other ideas as well, but I'll see how this performs.

[Happycarz]

Ted,

I put an air bag isolation solenoid between the tank and ride height valve, both for the front tank and rear tank. When I dump the air bags the tanks stay full. Fortunately, both my air tanks are up front, so I didn’t have to run a wire to rear of coach for that solenoid.

Attachment 388696

With insulation, it would be wise to use one with a decoupling layer, like Monaco used in the engine compartment and the firewall.


https://defender.com/en_us/soundown-...-barrier-layer

https://www.westmarine.com/west-mari...pe-216858.html

https://www.soundproofcow.com/produc...y-composite-2/

[Ted DuPuis]

Good thoughts, Harry. I like the idea of the decoupling solenoid, that would be a good one. Your attachment link didn't work for me - was there a thread you posted about this? That might be another alternative to my problem. Interested how you wired it.

[Happycarz]

Let’s try for the picture of my air bag isolation switch again.

Attachment 388721

You can have a Contura switch with custom label made,now. I didn’t have that option years ago.

https://www.otrattw.net/Plain-and-Text-Only-Contura-V/