DIY resonator!

[m880cummins]

As many of you probably know, when the muffler is chopped out of your system, you get a drone under load around 1700-3000 rpms. Sometimes it's so bad I will get tired a lot quicker while driving, you can't hear your passenger well (if you have one) and it is outright annoying. Usually if you have any exhaust pipe going a size bigger, it will create a drone. I did some research on droning exhaust and there's plenty of physics involved and several online calculators where you can enter in your exhaust diameter, length etc etc etc.

I don't have the URLs of the calculators on hand but they are out there and easy to find. I decided to wing it today to make a resonator. First, I had a 1.25" pipe in front of my 3-4" coupling behind the transfercase that would go to the side pipe. After that was welded on, I took it down the road a mile and really didn't notice a difference. When I put one downstream of the coupling I lost almost all drone and only heard the engine noise under the hood until I would romp on it. Even getting on it, I would have exhaust noise, but no drone! Pretty easy to do if you have a welder, grinder and hacksaw. I used 1.5" pipe about 10" long right at the bend for the side pipe. The length of the resonating pipe is dependent on the distance from the turbo. You cut the pipe at an angle on one end, then weld a cap on the other and that's all it is!



Charlie