Hi,

i had a custom dual exhaust made for the s2000. The sound is awsome, its pretty loud and i like it. Butt i have a huge
problem with drone between 2800-3900rpm. Is there any solution for that besides replacing the whole exhaust or cutting my oem
exhaust to use parts .

https://www.youtube.com/watch?v=M3lZOgBiroQ

s2000 (1 of 1) by Klemen Jeram, on Flickr

https://www.flickr.com/photos/136365...n/photostream/

https://www.flickr.com/photos/136365...n/photostream/

 

I was advised by a retailer I trust that ALL non-OEM S2000 exhausts drone. All of them. Some at different RPMs than others. Honda has a Helmholtz resonator in the exhaust -- that little sealed side pipe between the cat and first muffler -- to tune that out.

Here's a link to a 11 year old article (here) on the drone of the Invidia Q300 which looks remarkably like your custom system. I wish I'd read the article before I bought a Q300 earlier this year. Drones in the same range as your system.

https://www.s2ki.com/...xhaust-booming/

Here's a photo of my stock exhaust. The Helmholtz resonator is sticking off one side. This is an AP2 system, the AP1 system is slightly different.



Helmholtz resonators are commonly used in vehicle intake systems as well. There's one in the stock airbox.

-- Chuck

BTW I removed the Q300 and fitted the Tanabe Medalion Touring system. Only drone is a bit below 2000 rpm on deceleration. None in the 3000 - 4000 rpm cruising range.

 

I've used this race muffler on a couple of cars(V8) that had a lot of drone when at cruising speed. One was also just as loud outside as it was inside the car. This race muffler took away most of the drone and it took the edge of the exhaust. What it did not do was change the tone of the exhaust, so if you like the tone of your exhaust this is the first one I'd try. With nothing to burn out the tone and db's will not change over time like it can with a muffler that has packing that will burn out over time. But if you put it on it will lower the db's by around 4 to 6 db.

http://www.moroso.com/eb/catalog/nav...nuId=main.menu

ROD
You can get it cheaper here
http://www.summitracing.com/parts/mor-94050

 

Thanks for the response

we have fitted oem size helmholtz resonator to the exhaust. It didnt change much but its more controllable. Welder said because the pipes are bigger
than oem, (70mm to 2x60mm) we allso need bigger resonator and we have to determine the lenght of the helmholtz resonator. He suggested that we cut the end of the resonator and put a closed end pipe over it and try to move it so we can change the lenght and fine tune the resonator.

Il post if it works. if it doesnt, next we will replace the cat with test pipe

 

I have read good things about Vibrant Performance resonators. Might want to look into that maybe?

 

Ok, now we added helmholtz resonator to the oem spot and size. It did change a bit, the sound is more controlable. Before it was so booomin loug right in the brain and ears, but now its not hurting my brain . Im not saying it got quiet but its better.

Next we are going to play with the size because the pipes are 70mm. Im thinking of welding on resonator the same size as the CR exhaust.

If this doesnt work i will try with test pipe.

 

finaly the video

https://www.youtube.com/watch?v=8vASk_w01Bc

 

i am very happy to say that we fixed the drone issue from idle to 2900 zero drone, then from 2900-3100 a quick light drone and then the resonator kicks in again from 3100 to 4000rpm. 4k above the exhaust is the same as it was....loud but no drone .
Finaly!!!! everything is 50-70% quieter in cabin but it didnt change the exhaust tone, outside is still the same awsome sounding dual exhaust .

I used 60mm piping and the branch is aproxx... 81cm long i could cut it a few cm to fix the little 3k drone but i will leave it as it is .
pics:

WP_20160206_001[1] by Klemen Jeram, on Flickr

WP_20160206_002[1] by Klemen Jeram, on Flickr

 

 

Vibrant resonators will resolve it