Well, in my Mustang, the drone was so bad, it was driving me nuts. When I had 3.73 gears, it droned at about 60 mph. When I went to 3.31 gears, it moved up to around 75 mph. It was bad enough that after 15-20 minutes, I wanted out, even worse with the windows up. For note, my drone was between 1900 and about 2300 rpms. While searching for a solution, I came upon this thread on another site: https://www.corral.net/threads/exhaust-drone-is-completely-gone.496793/
After reading almost half of it, I decided it's cheap and easy enough to give it a try. Over the past winter, I collected the parts I needed and went to town.
Did some measuring and decided where I would put the extra tubes and mocked one side up.
After welding
Decided to use a slip joint after the elbow so if the pipe needed to be shortened, I wouldn't have to cut the other end and keep welding caps on.
Under the car
For the caps, I found some expansion plugs that fit snug in the pipe and just tacked them in.
If you're still reading and interested, these are 1/4 wave resonators. The reason these work is when the sound waves travel down the tube, reflect off the end cap, and re-enter the main pipe, the sound wave is 180 degrees out of phase, cancelling out the noise.
When doing this, I was really hoping I wasn't cutting holes in my exhaust for nothing, thinking "it works for everybody else, but it won't for me".
After all the waiting, I finally got to take the car out for a run. Not only is my drone completely gone, but now you can barely even hear the exhaust inside the car at 75 mph now. I can now listen to the radio on trips, or actually have a conversation inside now. Before doing this, I went from Borla Pro XS mufflers to the DynoMax Super Turbos. I've heard good things about them, but unfortunately they didn't do a thing for drone.
So, instead of changing mufflers you like trying to find something that won't drone, put a set of these resonators on and be done with it. There is a ton of info in the posted thread to figure out how to tune them. I got really lucky the first time on the length of the tubes as it was perfect. The second best part, with the car on the ground, you can't see any part of these. Sorry, I don't have any pictures of it completely done (thought I did), so if you want to see more, let me know and I'll get some.
After reading almost half of it, I decided it's cheap and easy enough to give it a try. Over the past winter, I collected the parts I needed and went to town.
Did some measuring and decided where I would put the extra tubes and mocked one side up.
After welding
Decided to use a slip joint after the elbow so if the pipe needed to be shortened, I wouldn't have to cut the other end and keep welding caps on.
Under the car
For the caps, I found some expansion plugs that fit snug in the pipe and just tacked them in.
If you're still reading and interested, these are 1/4 wave resonators. The reason these work is when the sound waves travel down the tube, reflect off the end cap, and re-enter the main pipe, the sound wave is 180 degrees out of phase, cancelling out the noise.
When doing this, I was really hoping I wasn't cutting holes in my exhaust for nothing, thinking "it works for everybody else, but it won't for me".
After all the waiting, I finally got to take the car out for a run. Not only is my drone completely gone, but now you can barely even hear the exhaust inside the car at 75 mph now. I can now listen to the radio on trips, or actually have a conversation inside now. Before doing this, I went from Borla Pro XS mufflers to the DynoMax Super Turbos. I've heard good things about them, but unfortunately they didn't do a thing for drone.
So, instead of changing mufflers you like trying to find something that won't drone, put a set of these resonators on and be done with it. There is a ton of info in the posted thread to figure out how to tune them. I got really lucky the first time on the length of the tubes as it was perfect. The second best part, with the car on the ground, you can't see any part of these. Sorry, I don't have any pictures of it completely done (thought I did), so if you want to see more, let me know and I'll get some.