Fancy Tech: How to Get Rid of Exhaust Drone, works great!

6MT · 07-29-2010, 09:48 AM

Why would you want to get rid of this so-called "drone"? I love that sound!! That's the best thing about my Stillen set-up! (Except for WOT burns, of course.)

'10Anamoly · 07-29-2010, 10:04 AM

Drone is the head pulsing vibration inside the cabin that gives people nasty headaches and hurts your ears if its too loud. If you like that, more power to you!

If you dont, thats why I wrote the article.

370Zsteve · 07-29-2010, 10:08 AM

My Berk exhaust makes it's sweetest sound right at the RPMs you specify.

Berk ftw?

Trips · 07-29-2010, 10:43 PM

Quote:

Originally Posted by 370Zsteve

My Berk exhaust makes it's sweetest sound right at the RPMs you specify.

Berk ftw?

Holliday · 07-30-2010, 01:26 AM

Quote:

Originally Posted by Triple's

Play nice you two!

'10Anamoly · 07-30-2010, 10:28 AM

Quote:

If there is temperature change in the exhaust due to outside ambient temps the speed of sound will change and the wave length will also be affected.

Frequency=Speed of sound/Wave Length

This may be a non-issue if the exhaust temps are not affected much by the outside temps.

my 2 cents

This is true for the math, but the exhaust temps should be pretty similar despite outside temperatures. Perhaps a bit cooler in the winter but still pretty close. The side branch resonators cover about 15 points of frequency completely and then begin to lose a bit of efficiency. On my car it knocked out all the drone from 2200rpms through 3000rpms. I expect in winter for the car to make a bit more noise but probably not much. Can always report back when its cold outside.

Nikon FM · 07-31-2010, 10:47 AM

Quote:

Originally Posted by '10Anamoly

This is true for the math, but the exhaust temps should be pretty similar despite outside temperatures. Perhaps a bit cooler in the winter but still pretty close. The side branch resonators cover about 15 points of frequency completely and then begin to lose a bit of efficiency. On my car it knocked out all the drone from 2200rpms through 3000rpms. I expect in winter for the car to make a bit more noise but probably not much. Can always report back when its cold outside.

Sounds good. 15 points=how much bandwidth?

Nice job on the Helmholtz solution!

Holliday · 07-29-2010, 10:17 AM

This is the same thing HKS used for their exhaust.

I can't stand drone either! +1 rep for all the engineering involved. I wish FI would have made an exhaust that did not drone so bad.

'10Anamoly · 07-29-2010, 10:34 AM

The HKS canisters are different. Those are resonator chambers (notice how they are big on one end like a resonator and arent just straight piping capped off at the end) with perferated holes in them and packing, probably a more expensive version tuned to do the same thing in a smaller space. This article is mainly for the FI guys who have drone and want to fix it but that is the idea.

The Saclam exhaust however has side branch resonators, its the side pipes people were calling backpressure tubes. Check out the layout, they just put theirs further up the exhaust system. It's probably why their exhaust sounds like a race car up top and doesn't kill your eardrums cruising around inside the cabin. The pipes in the middle that parallel the main exhaust pipes are side branch resonators, the length clearly tuned by Saclam to get the note they wanted.

lllll210lllll · 08-04-2010, 02:30 PM

Quote:

Originally Posted by 6MT

Why would you want to get rid of this so-called "drone"? I love that sound!! That's the best thing about my Stillen set-up! (Except for WOT burns, of course.)

WOT burns? black on ur bumper??????

'10Anamoly · 08-04-2010, 02:52 PM

Yes, you have to use a hole saw to open up a 2" to 2.25" hole on the FI exhaust. That is where the sound waves travel through, down the resonator pipe, and back to cancel out the droning frequencies.

It's a trade off, keep the drone and dont touch the pretty exhaust or mod the exhaust and enjoy the silence (lack of drone, depeche mode style).

docaam · 08-04-2010, 10:03 PM

Quote:

Originally Posted by '10Anamoly

Yes, you have to use a hole saw to open up a 2" to 2.25" hole on the FI exhaust. That is where the sound waves travel through, down the resonator pipe, and back to cancel out the droning frequencies.

It's a trade off, keep the drone and dont touch the pretty exhaust or mod the exhaust and enjoy the silence (lack of drone, depeche mode style).

Im big Depeche mode fan

.... just trying to prepare myself to get this done as need it badly, lets see if someone with FI exhausts wants to do before me

docaam · 08-10-2010, 02:52 AM

Quote:

Originally Posted by '10Anamoly

Yes, you have to use a hole saw to open up a 2" to 2.25" hole on the FI exhaust. That is where the sound waves travel through, down the resonator pipe, and back to cancel out the droning frequencies.

It's a trade off, keep the drone and dont touch the pretty exhaust or mod the exhaust and enjoy the silence (lack of drone, depeche mode style).

Man when you posted this thread car was in workshop and I have been calculating this drone on rpm range...the vibration starts at 2100 and is there till 2800 depends on the gear and speed as sometime it dies on 2700. Its more if you stay in single gear and accelerate slowly all the way till 3000, but if you push the pedal hard then its a bit less.

So can you throw some light according to your calculations as I have no means to measure those frequencies.

For the pipes does those be in SS or normal exhaust pipe will do the trick. I am about to pull the trigger

by making hole in FI exhausts

'10Anamoly · 08-10-2010, 08:14 AM

Since the FI setup is the same pretty much as mine and the drone in is the same range, I would use 28-30" pipes, one per side. Any shorter and it will tune out drone above 3000rpms where you dont have the problem. Regular steel is fine but I would use some hi-temp paint to keep it from rusting ever.

07-29-2010, 09:48 AM	#1 (permalink)
6MT A True Z Fanatic Join Date: May 2009 Location: ITU Zone 2 Posts: 22,459 Drives: Reliant Robin Rep Power: 1792	Why would you want to get rid of this so-called "drone"? I love that sound!! That's the best thing about my Stillen set-up! (Except for WOT burns, of course.) __________________ Andrew 2009 370Z Sport/Touring 6MT sold 2013 Honda Civic Si coupe D/D

07-29-2010, 10:04 AM	#2 (permalink)
'10Anamoly Track Member Join Date: May 2010 Location: GA Posts: 882 Drives: 2010 370Z BS M6 Rep Power: 18	Drone is the head pulsing vibration inside the cabin that gives people nasty headaches and hurts your ears if its too loud. If you like that, more power to you! If you dont, thats why I wrote the article. __________________ 2013 Ford Mustang GT 374rwhp, 360rwtq SAE / GT500 Axle-Backs / Brembo Pack / Track Pack / Recaros / 6spd

07-29-2010, 10:08 AM	#3 (permalink)
370Zsteve A True Z Fanatic Join Date: Sep 2009 Location: Gold Coast CT Posts: 10,599 Drives: 2019 Corvette G.S. Rep Power: 44	My Berk exhaust makes it's sweetest sound right at the RPMs you specify. Berk ftw? __________________ SOLD MY Z MARCH 2018 - another Core OG moves on - new ride 2019 Z Corvette Grand Sport - no mods necessary but already have eyes on HFC and intakes LOL IT NEVER ENDS.

07-29-2010, 10:17 AM	#8 (permalink)
Holliday Track Member Join Date: Aug 2009 Location: Cache, OK Age: 40 Posts: 916 Drives: in the fast lane.... Rep Power: 18	This is the same thing HKS used for their exhaust. I can't stand drone either! +1 rep for all the engineering involved. I wish FI would have made an exhaust that did not drone so bad. ped likes this. __________________

08-04-2010, 02:52 PM	#11 (permalink)
'10Anamoly Track Member Join Date: May 2010 Location: GA Posts: 882 Drives: 2010 370Z BS M6 Rep Power: 18	Yes, you have to use a hole saw to open up a 2" to 2.25" hole on the FI exhaust. That is where the sound waves travel through, down the resonator pipe, and back to cancel out the droning frequencies. It's a trade off, keep the drone and dont touch the pretty exhaust or mod the exhaust and enjoy the silence (lack of drone, depeche mode style). __________________ 2013 Ford Mustang GT 374rwhp, 360rwtq SAE / GT500 Axle-Backs / Brembo Pack / Track Pack / Recaros / 6spd

08-10-2010, 08:14 AM	#14 (permalink)
'10Anamoly Track Member Join Date: May 2010 Location: GA Posts: 882 Drives: 2010 370Z BS M6 Rep Power: 18	Since the FI setup is the same pretty much as mine and the drone in is the same range, I would use 28-30" pipes, one per side. Any shorter and it will tune out drone above 3000rpms where you dont have the problem. Regular steel is fine but I would use some hi-temp paint to keep it from rusting ever. __________________ 2013 Ford Mustang GT 374rwhp, 360rwtq SAE / GT500 Axle-Backs / Brembo Pack / Track Pack / Recaros / 6spd

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