OK so I took off the rear mufflers couple months back and left everything else stock and was getting horrible cabin drone anywhere from 1500-2500 rpms. After doing a TON of research on some truck, mustang and f1 forums I read about branch resonators so I decided to change up my whole setup. See pics below.

Basically what I got is an x-pipe into the stock resonators and then some straights into another set of resonators and then out to the tips. Now what is different in the setup is the two 32'' 90 degree angled capped off pipes that are coming out of the straights. These are the branch resonators. The exhaust air will travel down its regular course however the drone sound will travel down the branch resonators, hit the closed cap and travel back..cancelling out the drone frequency. Its all physics but damn does it work. I get no drone at all now and still get to keep the mean VQ engine sound that we all love.

 

Vids now! that looks awesome lol

 

Have not seen ANYTHING like that on these cars,,, looks pretty sweet-sick!! does it sound good all the way up the rev range??

 

Could you post a vid of the sound please? I'm really interested in this!

 

Just one question, do the branches need to be that long?

 

This is great!!

 

Chambers like this can definitely work, but besides affecting the sound, this can also affect exhaust (back) pressure. There is quite a science to it actually; see this thread for sound considerations: https://g35driver.com/forums/intake-...technical.html

Properly done, they can actually draw more flow out of an otherwise identical exhaust, or they can create an out-of-sync pressure wave which may reduce overall flow at certain rpms.

 

The length of the resonators depend on when your specific drone is the worst in ratio to RPMs. For example 31-32'' was recommended when the drone is the worst around 2000 RPM which was the case with my setup. The link vqsmile provided may have the info that you need to calculate your specific length.

FYI: If you cant tell when the drone is the worst then download a dB reader app, sit in your car and go for a joyride.

 

Did you ever make a sound clip?

 

you have too much money....please send some my way.

 

I have a similar drone issue after doing the muffler delete and replacing it with a section of straight pipes.

If I add the two 32'' 90 degree angled capped off pipes to where the straight pipes are, do you think it will remove the drone? Do I need to incorporate your other mods(adding additional resonators to where the mufflers were before, x pipe through resonators)

 

What type of resonators did you place after the straight pipes (where the stock mufflers used to be)?

 

Just saw your thread and I have been testing the branch side resonators and have had no luck. I have a 2007 g35 sedan and was wondering if you can help me with the same setup you have. I also have a thread with pictures and hz. I am not able to view your picture setup if you can kindly help. Thank you

https://g35driver.com/forums/g35-sedan-v36-2007-08/459512-2007-g35-sedan-drone-2000-rpm-branch-resonator-helmholtz-resonators.html#post7104157


QUOTE=TaBzRx;6510379]OK so I took off the rear mufflers couple months back and left everything else stock and was getting horrible cabin drone anywhere from 1500-2500 rpms. After doing a TON of research on some truck, mustang and f1 forums I read about branch resonators so I decided to change up my whole setup. See pics below.

Basically what I got is an x-pipe into the stock resonators and then some straights into another set of resonators and then out to the tips. Now what is different in the setup is the two 32'' 90 degree angled capped off pipes that are coming out of the straights. These are the branch resonators. The exhaust air will travel down its regular course however the drone sound will travel down the branch resonators, hit the closed cap and travel back..cancelling out the drone frequency. Its all physics but damn does it work. I get no drone at all now and still get to keep the mean VQ engine sound that we all love.






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