The generator is a noisy beast.
The noise comes from 3 major places.
The exhaust. The engine. The intake.
There is a small amount of noise from the generator unit itself, but it’s nothing compared to the other 3.
The first thing to tackle is the exhaust.
I don’t want to get into all the things I did to test this, but know that it took a couple of weeks of testing and ripping it apart and retesting.
I don’t really understand why, but no matter what, you MUST use the factory muffler as a part of the exhaust system.
Without it, the exhaust noise is harsh and loud.
Even with an additional muffler attached.
But together, there is almost no noise out of the tailpipe.
The build will go as follows:
Build a custom header to come off the engine.
Route it out the bottom so it will go below the rear of the truck.
Where it will connect with the factory muffler, which will be connected to an automotive muffler.
The tail pipe will be routed out the drivers side of the truck, and directed upwards.
I will construct a DIY genturi pipe and send it out near the top of the truck.
The factory muffler is where the majority of the heat is collected.
I want to move the factory muffler away from the generator so the heat is not contained within the box.
In order to do this, I needed to build a custom header.
This directs most of the sound and heat out and away from the generator unit.
Use header wrap to contain the heat within the pipe, so that it stays outside of the box.
Most auto parts stores will carry it. But it can be pricey.
Way cheaper to get on Amazon or Ebay.
If you can wait for delivery.
NOTE: This stuff is FIBERGLASS.
Wear gloves, mask, and coveralls. You will still probably itch for a week.
Also helps to soak it in water before wrapping the pipe.
To contain the heat even more and minimize any heat in the box….
I am also going to figure out a way to try to encase this pipe with cement board, and make a metal heat shield.
I got a lot of inspiration from ALL of the other sites I read that are trying to do the same thing…. quiet a generator. ( forever grateful to them )
One of them showed this style of custom header, but they welded a sharp 90 bend right to the flange. It was only an inch or two long, then straight down.
I DID try this. The result was that the 90 bend was red hot in minutes!!
Maybe it’s because my generator is larger.
But it needs to flow smoothly.
Just wanted to mention it.
If you can buy the flanges locally for a good price at some supply store, go for it.
I spent a whole day trying to find some, only to find out they wanted $12 a piece for them.
I think not.
The ones I made were twice as thick.
I used some 3/8 inch thick flat steel and traced out the exhaust flange, using the original as the template.
I first bored out the center with a hole saw.
Then drilled out the mounting holes.
Then cut it out on the metal cutting bandsaw, and later used the grinder to shape the edges.
This little piece is the result of an hour and a half worth of work.
Oh yeah, time well spent.
I had this pipe laying around from some other old project.
It was about 3/4 OD ( I did not measure it )
And about 1/4 inch thick. Good and heavy.
I welded the flange to the pipe.
I screwed it up the first time, and had to cut it off and re weld it.
Also welded a threaded coupler to the other end.
Cleaned it up a little with the grinder.
I made a couple more flanges, for more connections.
Since these ones will not be attached to the head,
I figured they don’t need be shaped so nice.
Maybe I was just too lazy.