New Exhaust Droning Bad

[Thomas_D]

G'day folks
Car is a VF2.
Have just fitted a full Hurricane system, 1" 3/4 primaries, high flow cats(100cells), 3 inch midpipes,high flow mufflers. Have retained the bi-modal function.
The sound(note) is absolutely phenomenal, however the drone is fierce between 1500 and 2200 rpm or if engine is under some load. It's seriously tinnitus-inducing.
Do these things settle down after a week or so?
What is the biggest contributing factor to drone? Midpipe or mufflers? Using the bi-modal in quiet mode reduces some noise which I appreciate will keep the neighbours happy but the drone is almost as bad. I will contact Hurricane directly and hopefully they can suggest a fix.
Cheers

 

[Skylarking]

... Do these things settle down after a week or so?...

Playing a bugle for months won’t change the sounds that come from such a brass wind instrument, notwithstanding the players skill.

Likewise driving for months won’t change the sound that comes from an exhaust... Such is a function of the design of the exhaust and based on tube harmonics

Some imply that a build up of carbon within the exhaust reduces the tinny sound but the notes and drones produced are a function of the harmonics and won’t change with time

You’d have to fiddle with the exhaust harmonics to reduce drone and that implies changes in the pipework

Well that’s how I understand it anyway

 

[Thomas_D]

Playing a bugle for months won’t change the sounds that come from such a brass wind instrument, notwithstanding the players skill.

Likewise driving for months won’t change the sound that comes from an exhaust... Such is a function of the design of the exhaust and based on tube harmonics

Some imply that a build up of carbon within the exhaust reduces the tinny sound but the notes and drones produced are a function of the harmonics and won’t change with time

You’d have to fiddle with the exhaust harmonics to reduce drone and that implies changes in the pipework

Well that’s how I understand it anyway

I heard somewhere mentioned 'Helmholtz' pipes?

 

[Chuckmeister]

I feel my exhaust has changed note considerably since I had it put on. It seems to have mellowed a ton and the droning that I had initially seems to be gone.
Mind you, I have had my car cammed since but its not like the same exhaust sound, with revs and torque. I have pretty ordinary hearing at my age too...who knows but I think it sounds better than it did when new.

 

[Skylarking]

I feel my exhaust has changed note considerably since I had it put on. It seems to have mellowed a ton and the droning that I had initially seems to be gone.
Mind you, I have had my car cammed since but its not like the same exhaust sound, with revs and torque. I have pretty ordinary hearing at my age too...who knows but I think it sounds better than it did when new.

There’s no logical reason for an exhaust to change sound without something changing within the pipework or the engine.... if there is I’d love to hear the theories

But if you’ve noticed a big mellowing change, may be time for a hearing test

 

[[paradox]]

they do carbon up.. but they dont change too much

 

[Not_An_Abba_Fan]

Exhaust note will change due to a few factors, number one being carbon. As the exhaust carbons up it will sound different inside the car. Another is the glass packing inside the mufflers loosens up a bit, also changing the note.

The main thing that contributes to drone is the mismatching of components. Most companies slap a system together based on theory without actual physical real world testing. A few companies will frequency match their mufflers and resonators and also add frequency enhancing/cancelling components like Hemholtz chambers, H pipes and in the case of Manta, they have a different internal in their left and right sides of their front mufflers on the VE/VF systems. There is a lot that goes into a nice sounding exhaust, and while Hurricane do build a nice system (I prefer their extractors and had sold them for 10 years) it doesn't sound very good in my opinion.

If you have the system with the 4 hotdogs in the front, a H pipe fitted in between the two sets of hotdogs may help. I have even added 2 H pipes into a system before and it almost eliminated the drone.

Playing a bugle for months won’t change the sounds that come from such a brass wind instrument, notwithstanding the players skill.

Likewise driving for months won’t change the sound that comes from an exhaust... Such is a function of the design of the exhaust and based on tube harmonics

Some imply that a build up of carbon within the exhaust reduces the tinny sound but the notes and drones produced are a function of the harmonics and won’t change with time

You’d have to fiddle with the exhaust harmonics to reduce drone and that implies changes in the pipework

Well that’s how I understand it anyway

If you could somehow paint the inside of that bugle with a 1mm thick layer of carbon it will absolutely change the tone of it.

 

[mpower]

J-Pipes

 

[Thomas_D]

Exhaust note will change due to a few factors, number one being carbon. As the exhaust carbons up it will sound different inside the car. Another is the glass packing inside the mufflers loosens up a bit, also changing the note.

The main thing that contributes to drone is the mismatching of components. Most companies slap a system together based on theory without actual physical real world testing. A few companies will frequency match their mufflers and resonators and also add frequency enhancing/cancelling components like Hemholtz chambers, H pipes and in the case of Manta, they have a different internal in their left and right sides of their front mufflers on the VE/VF systems. There is a lot that goes into a nice sounding exhaust, and while Hurricane do build a nice system (I prefer their extractors and had sold them for 10 years) it doesn't sound very good in my opinion.

If you have the system with the 4 hotdogs in the front, a H pipe fitted in between the two sets of hotdogs may help. I have even added 2 H pipes into a system before and it almost eliminated the drone.



If you could somehow paint the inside of that bugle with a 1mm thick layer of carbon it will absolutely change the tone of it.

Great info, thank you
I'll post back once they've modified it.

 

[Thomas_D]

PS. All else being the same, does the 3inch drone more than the 2.5inch, or is it just louder regardless of drone levels?