reducing drone

Matt · 11-27-2009, 06:30 PM

Quote:

Originally Posted by Matt

My fear with Stillen, and potentially the future Berk CBE, is that it won't be loud enough. If I have to deal with a little drone to get the tone of the FI, so be it.

How aggressive is the stillen? From the look of the muffler design, I wouldn't guess it's too loud at all, just a little throatier than stock.

I'm looking hard at FI and Berk right now.

m4a1mustang · 11-27-2009, 06:51 PM

Quote:

Originally Posted by Matt

I think the Stillen CBE alone sounds good, but if you throw HFCs on it really sounds like crap. Some CBEs get very raspy when you add HFCs and the Stillen is one of those.

Zsteve · 11-27-2009, 04:58 PM

Quote:

Originally Posted by imag

Look at it this way - you're making those of us who went with Stillen feel better about it

So Stillen doesnt drone any?

imag · 11-27-2009, 05:28 PM

Quote:

Originally Posted by Zsteve

So Stillen doesnt drone any?

Not that I can tell. It sounds better, but noticeably louder, at low RPMs.

Modshack · 11-27-2009, 06:27 PM

Quote:

Originally Posted by Zsteve

So Stillen doesnt drone any?

No drone from the Stillen..

m4a1mustang · 11-27-2009, 05:07 PM

Quote:

Originally Posted by imag

Look at it this way - you're making those of us who went with Stillen feel better about it

That's fine. I just make sure to be honest when giving feedback. I love the sound of my FI CBE and don't regret getting it. Yes, there is some drone at 2k but the benefit far outweighs the cost. I have heard the Stillen setup and some others and they all sound raspy to me... the only one with absolutely ZERO rasp is FI... it puts the others to shame, IMO.

If you like it, that's great. That's all that matters.

I can't count how many times I have said how much I like this exhaust, yet people continue to rag on me for talking about drone. It's ridiculous and plain childish!

Zsteve · 11-27-2009, 04:54 PM

After researching and all, I have found that almost all aftermarket exhausts will have the 2K drone and that is the only time I am getting it, when around 60 mph in "D" mode at around 2k rpms. When with the wife who likes to talk while I drive its noticable but when its just me and Im usually on the gas I get that nice deep growl I like. And when Im driving at that one point it does drone I usually have the stereo up load and dont hear it. Just when the wife is with me that its a little loud. Now I willsay I love the tone of this exhaust better than any other one I heard on here so far and there are gains. Just wondering if I can cut down on the 2K drone some. Also I have the 7AT which might make a diff with the drone. So going to 18s will or wont help with this?

m4a1mustang · 11-27-2009, 05:10 PM

Quote:

Originally Posted by Zsteve

After researching and all, I have found that almost all aftermarket exhausts will have the 2K drone and that is the only time I am getting it, when around 60 mph in "D" mode at around 2k rpms. When with the wife who likes to talk while I drive its noticable but when its just me and Im usually on the gas I get that nice deep growl I like. And when Im driving at that one point it does drone I usually have the stereo up load and dont hear it. Just when the wife is with me that its a little loud. Now I willsay I love the tone of this exhaust better than any other one I heard on here so far and there are gains. Just wondering if I can cut down on the 2K drone some. Also I have the 7AT which might make a diff with the drone. So going to 18s will or wont help with this?

We'd have to ask Tony about the difference the resonators would make.

I am the same way as you. My girlfriend has sensitive hearing so not just the drone, but the volume alone bothers her on any extended trips.

When I am by myself I am not bothered. It's there, but it's not a real bother. The ECU whine cuts through the drone and pierces my ears anyways. That's the only thing in the car noise-wise that bothers me. Actually it kills me.

Zsteve · 11-27-2009, 06:26 PM

Quote:

Originally Posted by m4a1mustang

We'd have to ask Tony about the difference the resonators would make.

I am the same way as you. My girlfriend has sensitive hearing so not just the drone, but the volume alone bothers her on any extended trips.

When I am by myself I am not bothered. It's there, but it's not a real bother. The ECU whine cuts through the drone and pierces my ears anyways. That's the only thing in the car noise-wise that bothers me. Actually it kills me.

So far no ECU noise for me that I can hear but I have slight hearing loss at the 6K freq anyway.

Zsteve · 11-27-2009, 06:48 PM

Was doing some research and read that side branch resonators seemed to help the drone by getting the freqs 180 degrees out of phase with each other that end up canceling each other. Is that why the Saclam exhaust looks the way it does? I was wondering if adding something like that would help reduce it but keep the same tone.

Still, I love the tone of the exhaust so I guees the wife just cant ride in it as much, cuz when Im alone in it Im hardly ever at the 2K range for my style of driving (FAST).

After reading more into their exhaust it seems that the Saclam has added side pipes to help with drone.

Zsteve · 11-27-2009, 07:03 PM

So if add a side pipe would reduce drone even 50% what size diameter and length would be required? Looking for all the math/science guys on this one.

Modshack · 11-27-2009, 08:21 PM

Quote:

Originally Posted by Zsteve

So if add a side pipe would reduce drone even 50% what size diameter and length would be required? Looking for all the math/science guys on this one.

I think it's a litte more complex than that... Typically those chambers are called Helmholtz resonators. They are used to dampen resonances
but usually used in intakes. There is one on the Z in the drivers side intake accordion. You'll see them on many cars in various shapes, tuned to cancel out natural frequencies. I think it would take some smart acoustical engineer to come up with something for the exhaust that would work on your system..

Nikon FM · 11-27-2009, 10:50 PM

Quote:

Originally Posted by Modshack

I think it's a litte more complex than that... Typically those chambers are called Helmholtz resonators. They are used to dampen resonances
but usually used in intakes. There is one on the Z in the drivers side intake accordion. You'll see them on many cars in various shapes, tuned to cancel out natural frequencies. I think it would take some smart acoustical engineer to come up with something for the exhaust that would work on your system..

Ark Performance - Type 2 Stainless Steel True-Dual Exhaust

"Here's my 2 cents:

Essentially the second set of pipes are Helmholtz resonators, this is purely acoustic in nature and not necessarily performance related. The performance related aspects of this system can be attributed to the less restrictive flow path compared to the OEM system (including the x-pipe). The design "engineers" need to speak up to a level of explanation that does not give away their tricks.

I like this system, I think I'll purchase it but will not move until we see comparative dynos."

The side branches most likely are targeting a limited RPM range where flow conditions set up the "drone". The ~2k rpm condition (where drone occurs) is probably the targeted design point for the resonators. Higher RPMs mean a different flow so this becomes an off condition for the resonator design and the side pipes are there for looks.....but I kind of like them anyway

Done with the book...

TeamARK · 11-28-2009, 02:17 AM

Quote:

Originally Posted by Nikon FM

Ark Performance - Type 2 Stainless Steel True-Dual Exhaust

"Here's my 2 cents:

Essentially the second set of pipes are Helmholtz resonators, this is purely acoustic in nature and not necessarily performance related. The performance related aspects of this system can be attributed to the less restrictive flow path compared to the OEM system (including the x-pipe). The design "engineers" need to speak up to a level of explanation that does not give away their tricks.

I like this system, I think I'll purchase it but will not move until we see comparative dynos."

The side branches most likely are targeting a limited RPM range where flow conditions set up the "drone". The ~2k rpm condition (where drone occurs) is probably the targeted design point for the resonators. Higher RPMs mean a different flow so this becomes an off condition for the resonator design and the side pipes are there for looks.....but I kind of like them anyway

Done with the book...

I would want the customers to have it any other way. Our final production comes in Dec 15th. We have already set aside a day to bring detailed results with videos. Until then, if you have any questions regarding our systems please do not hesitate to ask.

Alex

m4a1mustang · 11-27-2009, 07:12 PM

I think that would just end up being an epic waste of money. I thought the Saclam exhaust had cutouts to bypass the muffler anyways... i know nothing about side tube resonators... if they exist... and if they even work.

11-27-2009, 04:54 PM	#7 (permalink)
Zsteve A True Z Fanatic Join Date: Sep 2009 Location: TX Posts: 3,298 Drives: the 2 balled club Rep Power: 22	After researching and all, I have found that almost all aftermarket exhausts will have the 2K drone and that is the only time I am getting it, when around 60 mph in "D" mode at around 2k rpms. When with the wife who likes to talk while I drive its noticable but when its just me and Im usually on the gas I get that nice deep growl I like. And when Im driving at that one point it does drone I usually have the stereo up load and dont hear it. Just when the wife is with me that its a little loud. Now I willsay I love the tone of this exhaust better than any other one I heard on here so far and there are gains. Just wondering if I can cut down on the 2K drone some. Also I have the 7AT which might make a diff with the drone. So going to 18s will or wont help with this? __________________ 2010 LS3 C6 Silver coupe corvette

11-27-2009, 06:48 PM	#10 (permalink)
Zsteve A True Z Fanatic Join Date: Sep 2009 Location: TX Posts: 3,298 Drives: the 2 balled club Rep Power: 22	Was doing some research and read that side branch resonators seemed to help the drone by getting the freqs 180 degrees out of phase with each other that end up canceling each other. Is that why the Saclam exhaust looks the way it does? I was wondering if adding something like that would help reduce it but keep the same tone. Still, I love the tone of the exhaust so I guees the wife just cant ride in it as much, cuz when Im alone in it Im hardly ever at the 2K range for my style of driving (FAST). After reading more into their exhaust it seems that the Saclam has added side pipes to help with drone. __________________ 2010 LS3 C6 Silver coupe corvette Last edited by Zsteve; 11-27-2009 at 06:59 PM. Reason: added the last line

11-27-2009, 07:03 PM	#11 (permalink)
Zsteve A True Z Fanatic Join Date: Sep 2009 Location: TX Posts: 3,298 Drives: the 2 balled club Rep Power: 22	So if add a side pipe would reduce drone even 50% what size diameter and length would be required? Looking for all the math/science guys on this one. __________________ 2010 LS3 C6 Silver coupe corvette

11-27-2009, 07:12 PM	#15 (permalink)
m4a1mustang A True Z Fanatic Join Date: Feb 2009 Location: Northern VA Posts: 55,385 Drives: on two wheels Rep Power: 6963	I think that would just end up being an epic waste of money. I thought the Saclam exhaust had cutouts to bypass the muffler anyways... i know nothing about side tube resonators... if they exist... and if they even work. __________________ - Steve Zs & Coffee - Saturdays at 10AM in Fairfax, VA and Columbia, MD (Click the banner!) LIKE us on Facebook!