Forum Discussion

deltabravo's avatar
Feb 21, 2022

Upgrades to make my generator quieter

Early last summer I installed the new Cummins Onan 2500i inverter generator in my AF 992. Later in the summer I added the Cummins Onan resonator

I did some sound comparisons with and without the resonator in this video

Without the resonator, If you are standing off to the side, at a 90 degree angle to the exhaust, you don't really hear the sputtering as much as you do if you are anywhere less than 90 degrees, and closer to the exhaust.

What I noticed after watching other videos on the resonator is that it makes an even bigger difference in noise reduction on the non inverter generator - the sputtering those make is pretty obnoxious.
If you have space to install the resonator and use your onboard genny a lot, it's a worthwhile upgrade.

Even without the resonator, the new inverter style gen is quieter than the generator I removed, as compared in this video sound test old vs new

My intention was to install the new gen in a TT I had, but I abruptly decided to sell the TT. I had already purchased the new gen, so I needed to put it to use. I decided to install it in the 992.

Before I installed the new gen, I installed some sound deadening mat in the gen compartment. Someone in the AF truck camper group recommended it.
Here's a short video describing that project: sound deadening mat in gen compartment
  • specta wrote:
    How long do you run your generator for??


    At least an hour at a time.

    I didn't use it much last summer after installing it because most of my trips were long weekend getaways, 3 day weekends.
  • Here is a pic of my custom exhaust install on the new Cummins Onan 2500i inverter generator (AF 990) utilizing the Cummins Exhaust Resonator (P/N 0155-2449)

  • NVR2L82AV8 wrote:
    Here is a pic of my custom exhaust install on the new Cummins Onan 2500i inverter generator (AF 990) utilizing the Cummins Exhaust Resonator (P/N 0155-2449)


    How long have you had your new model gen?

    It looks like there isn't much clearance between the BBQ propane line and the resonator.

    My propane line for the BBQ QD fitting was routed differently than yours.

    I like how yours is routed out the back though. That's something I should have done. The problem I found is that no exhaust shops have dies to bend this small of tubing.
  • deltabravo wrote:
    specta wrote:
    How long do you run your generator for??


    At least an hour at a time.

    I didn't use it much last summer after installing it because most of my trips were long weekend getaways, 3 day weekends.


    From what you've spent on the new generator and other upgrades to it I would have thought it ran for hours on end.
  • specta wrote:
    From what you've spent on the new generator and other upgrades to it I would have thought it ran for hours on end.


    I had planned on using the gen a lot more than I did last summer, but the summer was scorching hot in WA, all summer long.

    The only "long" trip I did was over 4th of July week. Due to the heat, I decided to stay at an RV park instead of dry camping, that way I could keep the rig cool all day by leaving the A/C on when I was out exploring the back country on my DRZ 400 dual sport bike.

    The rest of my trips were weekend getaways to the same area, but I camped in the shade. The weather wasn't quite as hot on those trips, so I didn't use the A/C much when dry camped.
  • Excellent report. I did a similar job but just a repair of the generator that was in there. Don't mean to highjack your post.

    It was a rusted mess that I cleaned painted and reinstalled with the new resonator. I too noticed an immediate sound difference inside but not really outside.
    The baffle was popped and was pretty easy to repair.

    The repair.

    Sound deadening material.

    reinstalled.

    That was some time back and have since replaced with my new portable Gens.

    It's a lot of work!!!!
    Joe
  • specta wrote:
    From what you've spent on the new generator and other upgrades

    Where was there a mention of how much money was spent on the generator and upgrades?