Eliminating drone with helmholtz resonators...Let's get technical - Page 3 - - Infiniti G35 & G37 Forum Discussion | rupromenergo.ru
Show Your Support Become A Premier Member

    > > >
  • Reload this Page >
    • Eliminating drone with helmholtz resonators...Let's get technical


Eliminating drone with helmholtz resonators...Let's get technical

Thread Tools Rating: Thread Rating: 4 votes, 5.00 average.
Old 03-06-2012, 03:52 PM
Registered User
iTrader: (33)
Join Date: Nov 2007
location: Burlingame/Berkeley, CA
Posts: 6,081
Thanked 1 Time in 1 Post
Can someone calculate the length I'd need if my drone is around 100-120Hz?
Old 03-07-2012, 11:13 AM
Registered User
Thread Starter
iTrader: (6)
Join Date: Feb 2010
location: Tampa, FL
Posts: 809
Thanked 27 Times in 25 Posts
Approx. 34.4" for 100Hz drone and 28.7" for 120Hz drone for a quarter-wave resonator. Helmholtz would be different.

That is too large of a range for the quarter-wave resonator to cancel out, so I'd probably build something in the middle of the two for 110Hz (31.3"). That should work pretty good to cancel out the drone range.
Old 03-07-2012, 03:38 PM
Registered User
iTrader: (33)
Join Date: Nov 2007
location: Burlingame/Berkeley, CA
Posts: 6,081
Thanked 1 Time in 1 Post
Hmm that seems pretty long. Does this take into account size of piping/volume? I have already installed two resonators but they didn't work so I'm trying to see how long they need to be . I have 2.5" piping and 8" long resonators at the ends, but I only made them ~18-19" long.

I also noticed the HKS exhaust has similar ones that are only 18" long, however the resonators they use are much larger in volume than the ones I have.

Last edited by elayman; 03-07-2012 at 04:09 PM.
Old 03-07-2012, 03:47 PM
Registered User
iTrader: (18)
Join Date: Mar 2009
location: Bremerton, Wa
Posts: 3,544
Thanked 148 Times in 112 Posts
I love this stuff!

Let's get technical!
Old 03-07-2012, 05:17 PM
Registered User
Thread Starter
iTrader: (6)
Join Date: Feb 2010
location: Tampa, FL
Posts: 809
Thanked 27 Times in 25 Posts
Quote:
Originally Posted by elayman View Post
Hmm that seems pretty long. Does this take into account size of piping/volume? I have already installed two resonators but they didn't work so I'm trying to see how long they need to be . I have 2.5" piping and 8" long resonators at the ends, but I only made them ~18-19" long.

I also noticed the HKS exhaust has similar ones that are only 18" long, however the resonators they use are much larger in volume than the ones I have.
A quarter-wave resonator doesn't take into consideration volume. That's for the helmholtz equation, like what the HKS uses. They are 2 different types of resonators.

I would try using the 31.3" quarter-wave resonators with the same diameter as your exhaust (2.5") and it should work. The 18-19" ones are definitely not long enough. With this type of resonator, you have to really be within +/- 2" of the correct length or it won't work well.
Old 03-07-2012, 05:21 PM
Registered User
iTrader: (33)
Join Date: Nov 2007
location: Burlingame/Berkeley, CA
Posts: 6,081
Thanked 1 Time in 1 Post
Quote:
Originally Posted by ryanm8 View Post
A quarter-wave resonator doesn't take into consideration volume. That's for the helmholtz equation, like what the HKS uses. They are 2 different types of resonators.

I would try using the 31.3" quarter-wave resonators with the same diameter as your exhaust (2.5") and it should work. The 18-19" ones are definitely not long enough. With this type of resonator, you have to really be within +/- 2" of the correct length or it won't work well.
Any idea how to calculate a helmholtz rezonator or what is necessary for one? I am using a resonator not just piping but I don't know the correct calculation.
Old 03-07-2012, 05:24 PM
Registered User
Thread Starter
iTrader: (6)
Join Date: Feb 2010
location: Tampa, FL
Posts: 809
Thanked 27 Times in 25 Posts
So...wait a sec... you have 2 side branch resonators coming off the main exhaust piping, and they have regular fiberglass resonators on them attached to straight piping?
Old 03-08-2012, 12:38 AM
Registered User
iTrader: (33)
Join Date: Nov 2007
location: Burlingame/Berkeley, CA
Posts: 6,081
Thanked 1 Time in 1 Post
Quote:
Originally Posted by ryanm8 View Post
So...wait a sec... you have 2 side branch resonators coming off the main exhaust piping, and they have regular fiberglass resonators on them attached to straight piping?
Correct.
Name: 355227e6.jpg
Views: 1237
Size: 77.1 KB

Here is what I was basing it off of:
HKS Exhaust:
Old 03-08-2012, 03:52 AM
Registered User
Thread Starter
iTrader: (6)
Join Date: Feb 2010
location: Tampa, FL
Posts: 809
Thanked 27 Times in 25 Posts
If you put a fiberglass resonator on the side branch, it will produce unpredictable results. That can't even be calculated. Once the sound waves pass through the fiberglass it will change the frequency and the noise cancellation won't occur. The side branch should always be an empty, dead chamber.

I would either remove the fiberglass resonator, or you can place it in the main exhaust piping and then recalculate the drone frequency so you can figure out what length side branch is needed.
Old 03-08-2012, 11:33 AM
Registered User
iTrader: (33)
Join Date: Nov 2007
location: Burlingame/Berkeley, CA
Posts: 6,081
Thanked 1 Time in 1 Post
Ah that makes sense. I guess I didn't take that into consideration. My motive behind using a resonator was the larger inner diameter would catch more frequencies and thus cancel a larger range, but I didn't think about the fiberglass packing.

Now, how do bends in the piping affect the performance? Can I have crazy bends, even >90* bends? Just thought I'd ask because I don't have a ton of room to route ~30" of piping
Old 03-08-2012, 12:35 PM
Registered User
Thread Starter
iTrader: (6)
Join Date: Feb 2010
location: Tampa, FL
Posts: 809
Thanked 27 Times in 25 Posts
If your bends are in the side branch, it won't affect performance at all. Generally you don't really want > 45 degree bends in main exhaust piping, but for the side branches it doesn't matter. Supposedly you can place the side branch anywhere and have any number of bends because there are only sound waves travelling through it.

Do you have room to place it near the midpipe? You could even have it come off the midpipe somewhere, and go towards the front of the car (it doesn't necessarily have to go towards the rear).
Old 12-29-2012, 01:55 AM
Registered User
Join Date: Dec 2012
Posts: 1
Thanks: 0
Thanked 0 Times in 0 Posts
Not to resurrect an old thread but i am in desperate need of help here. this appears to be exactly what I need. please see my thread at fsae its only 2 pages so not much. I have been researching this for almost a year now... please help!

Old 01-04-2013, 03:59 PM
Former rupromenergo.ru Vendor
iTrader: (5)
Join Date: Mar 2009
location: CHINO, CA
Posts: 880
Thanked 9 Times in 9 Posts
its also important where you place the quarter length resonators. Also you have to take a look into thickness of the pipes as well. This will help in eliminating a wider range of where drone occurs.
Old 01-05-2013, 01:11 PM
ttrank's Avatar
Grocery getter
iTrader: (57)
Join Date: Jul 2005
location: Phoenix
Posts: 27,304
Thanked 170 Times in 55 Posts
After a couple learning pain issues I finished my helmholtz resonators.

Here's one side.

Name: photo_zps4c24ff15.jpg
Views: 1698
Size: 105.9 KB
The Following 2 Users Say Thank You to ttrank For This Useful Post:
JaE35 (02-18-2013), SDGenius (01-05-2013)
Old 01-06-2013, 01:04 PM
re-crue13's Avatar
Registered User
iTrader: (4)
Join Date: Jul 2010
location: Western Colorado
Posts: 760
Thanked 36 Times in 32 Posts
Tim, I think we need a pic of the entire undercarriage, and what is that cooler for?

Related Topics
Thread Thread Starter Forum Replies Last Post
G35 Coupe Muffler Delete Sound Clip davizzle Video Share 5 01-31-2017 05:00 PM
Engine trouble vamarris Engine, Drivetrain & Forced-Induction 0 09-26-2015 01:56 PM
New guy from Ohio ChrisAult2004 New Members Check In 3 09-11-2015 11:33 PM
Help Identifying Ball Joint junon G35 Coupe V35 2003 - 07 1 09-05-2015 11:40 PM


Tags
14, auto, buy, calculation, closed, drone, eliminate, eliminating, end, exhaust, helmholtz, length, placement, proper, resonator, resonators, wave, work
Thread Tools
Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 11:40 PM.


Copyright ©2002 - 2017, rupromenergo.ru All Rights Reserved. We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in:

Related pages


chp 11 99 license plateremove carmax stickerkeep rotors from rusting2008 infiniti q35infiniti fx35 bluetoothsigns of too much transmission fluidpower acoustik nb 2 200 watt 3 way tweetersssr sp1 wheelsvq35de transmission350z on coiloversremoving badges from carsalpine mrv f540kicker ix ampold school kicker cvrdebadging a carcarmax jax flcigarette lighter aux cordautocouture wheelsfake bride seatskicker l7 subwoofer box370z nismo turboe85 seattlemyg37.comwood grain nardi steering wheelmyg37.comleaking valve cover gasket symptomsused tein coiloversnissan bossier city louisianafeal 441 coiloversscratch on windshield from wiperbride racing seats for salewhomp whomp whomp soundmy engine is making a ticking noisetein lowering springintercooler without turbo03 eclipse gts specscar cranks but wont start2005 350z 0-60ark exhaust 350zremove tint gluehome made tire cleaner12000 k hidinfiniti g35 vs g35xascd switchnismo rear bumperhow to scrape a pipemaxima org 6th geng35 hoodstock srt4g35 wheel bearing350z staggered wheelsinfiniti vpp leaseg35 single turbo kitwww onlinetires comgiovanni rimfastrak ticketcar is idling roughtint percentage comparisonhow to make your car backfire flamespaddle shifters aftermarketg35 turbo kitsbrakenetic reviewhercules raptis wr1 reviewvacuum leak smoke machinecar ramps for lowered carsaltima se-r forumcigarette lighter plug wiring diagramhow to change rod bearingshow often should power steering fluid be changedvalve cover gasket leak symptomskuroda auto body waipiofno1rc for saleinfiniti dealers torontowhich is better supercharger or turbo