Mr-T

The branch only has a small contribution. The main tune would come from the main resonator itself.
I went through a few iteration to balance size of resonator with ground clearance.

Original resonator was 5" dia, but this affected my ground clearance. I then swapped to a 3.5" dia and found it still worked, but caused a buzz sound at a certain RPM. (Larger dia is better, adjusting the length to keep the same volume).

My final was then the 4.5" dia that gave enough ground clearance while maintaining a good sized dia for the resonator.

If you want to tune on the fly, Id suggest making a sleeved main resonator, so you could adjust the volume. Then once tuned, either weld solid, or make a single piece resonator.

flanders

Packing the resonator should make the acoustical volume appear bigger due to the isothermal process.
It's the same mechanism when you are building subwoofers, stuffing it with fluff lowers the Q.
But it might be a bad idea in the long run since the packing material likely will degrade.

thomsbrain

Mr. T, how much did that thing weigh?

noodels

Atmospherics & heat changes drone <though my hearing sensitivity may change also> ,so adjustment being a variable ,via a valve is all I was thinking of.
If your design suits your exhaust, its a

EffWun

Mr-T

Sorry, no idea. Never weighed it. Not the lightest, but then aftermarket exhaust was lighter than OEM. Also mass was central to car at a very low point so little effect on CofG.

Yes, added weight is not idea, but eliminating the drone was well worth the sacrifice.

Jarman

Hi MR-T. Did it stop the the exhaust drone in the 3,000 - 4,000 rev range for you? I'm thinking of trying it on mine. It's a frustrating drive at the moment

Jarman

Would that fit on a Honda s2000?

Mr-T

Yes it should do. I had a Skunk2 system, which is very heavy on Drone. Managed to eliminate about 80% of it.

Jarman

Hi effwun. Did u get around to doing that side branch resonator. If so did it do the job for you. I'm looking for some advice on doing the same