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Registered:
August 2002
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 What creates drone?
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Tue, 11 November 2003 06:48
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In an exhaust system, what is the factor that creates drone?
is it the:
- Excessive pipe diameter
- Style of muffler
- Style of resonator
- Press/mandrel bent
- Number of bends in the pipe
Curious.
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Location:
Perth
Registered:
May 2003
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Re: What creates drone?
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Tue, 11 November 2003 07:05
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in my opinion the size of the pipe and muffler / resonator combo (eg big fukker muffler strait threw)
I've got a 2 1/2 strait threw that was single muffler it was loud as fuk but it had drone when id just cruize at like 80
i got a sticker for it and have since put a hot dog at the back and it's lost the bark up top (as well as the drone)
it still sounds sweet
it only cost me $20 to 
Dont you love having a brother who works at a Performance exaust shop 
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Location:
Adelaide, SA
Registered:
May 2002
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Re: What creates drone?
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Tue, 11 November 2003 07:39
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Not being an expert, but I'd say it was a lack of a resonator. My car had a shit 2" "performance" exhaust when I bought it and it was droning and loud as anything (7M NA). I had the 1jz with the same exhaust for a couple of weeks and it was worse - the exhaust was just a muffler and no resonator. Then I got a 2.5" with muffler and resonator - no drone, runs as quiet as. Went heaps better too.....
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I supported Toymods
Banned User
Location:
Brisbane
Registered:
May 2002
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Re: What creates drone?
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Tue, 11 November 2003 07:55
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Resonance is the cause of the dreaded drone  It has nothing to do with the size of the system! In fact you will get drone on any size or type of exhaust system at a certain rev point depending on the resonator! Its just that most resonators are designed to put the resonate frequency at a point in the rev range that wont cause any droning problems!
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Registered:
August 2002
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Re: What creates drone?
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Tue, 11 November 2003 08:12
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Prefer this to be based on sound theory rather than this and that, as there are too many independant variables to consider in such comparisons.
I am just wondering how to maximise exhaust diameter/flow and minimise drone.
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I supported Toymods
Banned User
Location:
Brisbane
Registered:
May 2002
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Re: What creates drone?
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Tue, 11 November 2003 08:19
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Its not just as easy as peiceing some bits togeather! You need to speak to someone that can figure out the calulations needed to design a resonator! They will need you to supply details such as exhaust diameter, exhaust box type and details on your engine.
So you are just best off going to a decent exhaust shop and getting them to design the system for you!
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: What creates drone?
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Tue, 11 November 2003 08:22
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well, drone is litereally resonance. you can do a bit of estimating by using the length of the pipe vs rpm and number of exhaust pulses etc...
one way to minimise drone is to break up long lengths of pipe into uneven, shorter lengths. this means the drone will occur at higher rpm, where you will notice less..
i did this with my exhaust, using 2 resonators.. pipe is 2" which is a little big for a 4K, but drone/resonance starts above 5500rpm, which is where the extractors are designed to resonate...
a few thoughts..
Cya, Stewart
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Registered:
August 2002
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Re: What creates drone?
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Tue, 11 November 2003 08:27
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My current system is awesome, it drones just before it screams, but alas the scream is the restriction and i know the exhaust is imposing a bit of a restriction.
P.S 2.25in press bent
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I supported Toymods
Banned User
Location:
Brisbane
Registered:
May 2002
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Re: What creates drone?
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Tue, 11 November 2003 08:29
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Any exhaust boxes or resonators?
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Registered:
August 2002
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Re: What creates drone?
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Tue, 11 November 2003 08:37
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oh its restrictive like i said
press bends
resonater
and a dogleg muffler
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I supported Toymods
Banned User
Location:
Brisbane
Registered:
May 2002
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Re: What creates drone?
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Tue, 11 November 2003 08:45
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Are you waiting for someone to say "dump the system and get another that isnt press bent?
Resonators are not really restrictive and you need it to keep the noise level down anyway! So you are only left with the pipe and the muffler!
When you say "dog leg" muffler do you mean straight through?
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Registered:
August 2002
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Re: What creates drone?
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Tue, 11 November 2003 08:50
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oh yeah someone will say mandrel, i know that
_
dog leg: the entry pipe is offset to the exit pipe _/
The resonator is straight through and isnt a restriction, however it is 2.25in
Thes question is do i dump it for a bigger system all up
Im running a 3inch hi flow cat as well.
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I supported Toymods
Banned User
Location:
Brisbane
Registered:
May 2002
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Location:
Bundaberg, Qld.
Registered:
May 2002
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Re: What creates drone?
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Tue, 11 November 2003 09:10
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 i like! this button!! !!!!! do you!!!!
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I supported Toymods
Banned User
Location:
Brisbane
Registered:
May 2002
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Re: What creates drone?
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Tue, 11 November 2003 09:13
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I like it when I am making an explanation!  Maybe you should learn some english skills 
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Registered:
August 2002
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Re: What creates drone?
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Tue, 11 November 2003 09:17
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Feral: WTF!?
Well the reason i dont want to dump it, is excessive drone created by a larger system.
Ie. trying to target the culprit of drone before proceeding.
Its currently 2.25 muffler everything bar the hi flow cat and is very quiet and almost no drone.
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I supported Toymods
Banned User
Location:
Brisbane
Registered:
May 2002
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Re: What creates drone?
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Tue, 11 November 2003 09:21
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Having a larger system doesnt mean its going to drone. Go and have a chat with a decent exhaust shop and tell them what you want. Make sure you tell them about yoru concerns when it comes to the droning and i'm sure they will be able to help you out!!!!
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Location:
mboro
Registered:
November 2003
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Re: What creates drone?
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Tue, 11 November 2003 09:47
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i reckon its a combination of rich mixture and well a bigger exhaust on the right application makes more power.
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Location:
Cabramatta, NSW
Registered:
May 2002
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Re: What creates drone?
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Tue, 11 November 2003 22:21
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I don't know that much about exhausts (apart from knowing that they're restrictive). 
Do all systems have resonators? 'Coz for all I know, I've got a cat and a straight through muffler... Although I get drone around 3,000rpm when the muffler is off...
BlackSupra, get rid of that exhaust!!!!!!! 2.25" press bent?!? URGH!
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Registered:
August 2002
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Re: What creates drone?
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Tue, 11 November 2003 23:28
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haha yes i know its rescritive nark, however its SUPER QUIET and doesnt DRONE!! Which i want in a system, so im not going to dump it for a 2.5 mandrel to find it drones.
My previous 2.5 mandrel system droned something vicious!
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Location:
Cabramatta, NSW
Registered:
May 2002
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 Re: What creates drone?
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Wed, 12 November 2003 00:52
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I passed the emissions noise test with my exhaust system.
That was with a different muffler though, this new one is a straight through so it's louder, but it's not what you'd call loud and it's not droney in any way.
Do it, your car will love you for it.
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Location:
Richmond NSW
Registered:
September 2003
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Re: What creates drone?
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Wed, 12 November 2003 09:02
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i dont no much either but i no when i put a 2' sports exhuast on my 7afe and thats all just the rear muffler it had the low down rev thing and then soon as i hit high rpm it all went away since i put my 20 v in its changed before if i wanted the nosie to go away i would hold it at a steady speed and it would go bye bye now the noise is always there but not overly loud unless ur in the back seat i think but still not excessivly loud. and now i have this nice high note high in the rev range which sounds good but i dont mind it but some of my friends reckon it gets to them but mehh is this cause of the resnator thing does it cause it to drone now but thing i dont understand is why didnt it do it b4 unless this is cause of the exctractors ??? any thoughts on this.
matt
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Location:
Sydney
Registered:
February 2003
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Re: What creates drone?
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Thu, 13 November 2003 07:30
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dude...punctuation
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Location:
Brisvegas
Registered:
June 2003
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Re: What creates drone?
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Thu, 13 November 2003 07:44
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number of "bends" will also play a factor...when the exhaust gas is being farted out it wants out asap...when it hits bends in the pipes it not only vibrates the exhaust itself but the gases are being knocked around from side to side changing the exhaust note
mandrel should be much quieter than press bend
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Location:
Richmond NSW
Registered:
September 2003
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Re: What creates drone?
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Thu, 13 November 2003 09:36
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mMehh had to type it before i forgot. So i was rushing.
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Location:
Sydney
Registered:
November 2002
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