Or, another Drone, Droning issue with exhaust.

Hi there,

I just had these made to my CM-A4S, noise is nice and engine is running freely now.

The problem is around 2,500 to 3,200RPM, then the noise or drone becomes very very loud. It invades the cabin.

Since then we've tried muffling tips, but that did not help, nor carpeting and sound isolation on the trunk ( I know I read that low frequencies are not helped by sound deading material).

The noise is loud to the point of disturb. Above that the noise is very low, the sound is great and nice, but around that "torque" range the noise becomes ubearable, very loud, disturbing and annoying.

Now, I tried to copy the design of those exhaust systems in the market, importing is out of question, so I found a good welder locally and did it.

A resonator pipe is an option, but labor intensive, wanted to resort this at last.

More hangers and better fixtures, and wrapper, has anyone tried these with good results?.

Cheers

 

Looks nice - but look like just straight pipe from the manifold to the back of the car...no cats or resonator ..... that would explain the droan.... might need to add a piece or two to absorb some of the droan

 

I ran a 3" exhaust on my turbo miata. I was able to get rid of the drone by running:

a 3" high flow cat
a 4" bullet style resonator
and a 22" x 11" x 5" straight through muffler. It's the largest I could fit on the Miata.





It's a very quiet highway ride, especially in a convertible.

 

The welder build a small resonator in the middle, around 3in, probably too small. Just ordered a 4 in Magnaflow to replace that, will try and will report.

The idea came from here:
https://www.northamericanmotoring.co...-and-pics.html


Also will fix couple additional hinges on the system.

Cheers

 

Well, after sometime batling with droning, I decided to go overboard and try several solutions.
One of them was to install a larger ressonator in the middle - got one from Magnaflow, but did not work, droning continued.




Then decided to make a bafling unit, two Hookers, with chambers and fiberglass pack inside - unfortunately cancelled most of the nice sound but drone is gone now:





Tips were a bezel cut, installed 45degress off angle.