Bloody exhaust drone/resonance

[FEM]

hey guys

I got 3" system with a resonator in the middle with a tri-flow muffler on the back

I have tried the cannon with the flap at the rear open and closed; redback chicane muffler and now the triflow.. installed today. I STILL CANT get rid of the damn drone that you get with low revs <4000rpm and closed throttle.

I hear that glass pack mufflers are the way to do and what not?

I dont know what to do? I cant stand it. i have splits in the front and rear with 2 subs and 2 amps.. and i can bearly hear it.. i can hear bass and some of the high vocals.. the rest is not hearable due to the damn exhaust!!

there is a real bad range about 1800-3000rpm where a KILLER.. seriously!

There is a site that i found on poogle: http://www.corral.net/forums/showthread.php?t=496793

some guy put a pipe that can run in any way shape or form in anywhere it fits with a closed end on it - sort of crimped. Sounds wave are not effected by bends like flow is; hence the reason why the pipe can be in any way it fits. now, theory AND reality has proved that this works.. all you need to work out is when the drone is (may be a few ranges) and counter it with the dead-end pipe. all we need to know is how long the pipe has to be to kill the drone.

I have a few ranges where i have the drone and will be getting a few pipes put on. this may sound silly but really, its under the car.. who is going to look???

i want to be able to talk to my passengers and listen to the stereo and have some SQ not SPL!!

So, if u know anything more about this sort of thing please give us a yell because i am interested!

Thanks

Dan

[Putonyourshoes]

is your car turbo?:)

[FEM]

yes

and pllllease please pleaaasee dont say thats the reason beacuse i have mates that have the same thing and its not loud

[Putonyourshoes]

yeah.. no its not the reason.. turbo-ing a car usually makes it quieter because the turbine smooths the flow of air through the exhaust..
i was going to say with an N/A car and a 3" exhaust its not going to be quiet..
im not sure i would be putting a pipe inside my exhaust with a turbo.. it might not be very fun in the future.. have you tried sound insulating? you could also try sticking a bigger resonator.. like one from a.. truck or something..
thats all i can think of for the moment.. sorry i cant help:(

[Rupewrecht]

i'd say it's the resonator. it's effectively a blockage in the system, and will be slowing down the flow of the exhaust gas

When i first got my 3" exhaust off another BA, it had 2 cats in it (probably because it was running a microleb :p), and once i had them both replaced with a single bigger one, it got rid of the same sort of resonance in the cabin.

[Putonyourshoes]

higher flow cat?

[FEM]

i dont ar... have.. a.. cat .. aylitic.. converter ? :O ahhahaha

nah what i am saying, its like a t piece.. there is no interuption to the flow of the zorst.. because the end is crimpled.. VERY little gas goes in there!

so what you do Dan? put a big cat in?

[Putonyourshoes]

http://www.raceinspired.com/c-35-adapter--silencer--sensor.aspx

[FEM]

ahh yeah, its the drone that i want to kill...

i dont mind the note.. its deep but the drone i CANT stand.

[FEM]

OHH YES!

http://naca.central.cranfield.ac.uk/reports/1954/naca-report-1192.pdf

[newman]

i think this is quite obvious.
1. get a decent high-flo cat. a because its the law, and b because it will be more effective in preventing the drone than your T piece or waht ever it is
2. loose the cannon mufler
3. what do you expect when you have closed throttle? its normal, don't like it then put your foot on the pedal ever so slightly
4. put stock exhaust back on

[FEM]

hmm...

i dont have the cannnon, if you read upwards it says i have a tri flow on atm
im not going back to a stockers and you CAN loose the drone thumping away with reso's and mufflers.. you need to tune the pipe to the freq.

the engine will always throw a drown out.. its how you tune the piupe to deal with it.. and the "T piece or what ever it is" is, if not, the best way of getting rid of it.. simply because you can tune that pipe to the freq of the drone..

why havent i done it? because i need to find out how to messure the freq in the range of drone ;)

i will be getting a cat too ;)

[Dutchy]

hey guys yeah rupe is dead right... come on we dont need this turning into some other "unnamed forums" that ive read through where all they do is "FLAME" each other, GHEY! :)

tinastar: i know what ur talking about, i researched quite heavily before i tuned my exhaust for my turbo. but there is alot involved in it and i cant remember it all... but hear goes...
first up you guys are right about the turbo making the system quiter but it is not because it is smoothing out the flow of the exhaust... the reason is that when the exhaust gas with the noise of the explosions hits the turbine the the flow of that gas by the laws of physics spins the turbine :eek: this results in some friction and heat, another part of this process is all the noise hitting the turbine blades, some of it makes its way through and the other part of it is absorbed into the blades of the turbine and converted into heat! yes true story.

but to the main event, u want to reduce this damn drone... i did too, i hate drone. But i wanted a free flowing exhaust to get the most out of my new turbo!
first up the cat is a good idea... if u find urself caught out with the cops and u have no cat or a smashed out one, the fine is alot more than the cost of the cat! also it will help to reduce the noise a little. and the loss of performance is very minimal as far as i know it is quite surprising how well they flow!
next go glass pack! i went glass pack because the nature of glass pack is to take out deep droning noise (that deep bassy ****) the sounds waves go into the glass and it absorbs them and turns the sound energy into heat also.
A glass pack hotdog to be more specific, half way down the system is a very good thing i believe that i could fit a 16" one in easily... my car is a bg too. the bigger/longer the better. u should only need one with a 5" diameter to get a pretty good result.. the lukeys are very good and are available at alot of places. The over all bigger dimensions of an exhaust component directly relate to how much noise that component will reduce.

next up the muffler... if that tri flow u have is a lukey glass pack KEEP IT! they are very good! the reason it is not working is cos the rest of the system is not helping it. :(

also the smaller the system is the less noise it will make... mine is only 2.5" but i get very good performance from it and i can quite happily drive from ballarat to sydney in it with out getting a headache or needing to blast the stereo! mind u i do give the stezza a red hot go!! :D

so there ya go man i hope it helps or just really confuses u! haha

cheers
Jeremy

[FEM]

Thanks Jeremy!

that really helps :)

as you know, i have a 3" so it will be naturally loud..

is there any brand in particular that you would recommend in terms of the cat? how big does it have to be? high flow?

So, you recommend getting a nice big glass packed muffler or resonator? About half way down the system yeh?

and get a glass pack at the rear too?

will it be better getting two in the middle and one at the back?

also, what design would recommend? straight through or triflow or ?? or is the glass pack a deisgn in its self?

Thanks Jeremy!!!

dan

[Dutchy]

yep that is definitely true about the three inch, i dare say its nice having the three inch but it could be worth asking urself whether u need it... an exhaust that big on this engine will contribute to either over boosting (bad) which will lead to boost or fuel cut on the stock ecu... which i did see u were having probs with...
my cat is a Lukey 2.5", i cant remember if it was hi flow or not, super cat i think they call them... it probably wouldnt make too much difference but someone could correct me on that.
yep i think that the biggest muff ull fit up the back is about 16" long, 4" high and 8" wide (oval). though it would pay to re-measure that! ;)

normal resonators are usually aimed at taking out more of the higher pitched noises i thnk, what u need is a helmholtz tuner this is what will taget those low tones. a good one is any type of hotdog with glass pack in it. and glass pack is just stuff that is added to normal exhaust parts to make then more efficient for their purpose. is looks like white fairy floss! :) and it basically gets put into the cavities in the muffler or what ever it maybe. it is built into it also. (ie ya cant add it later on, bung).

so for the middle i would recommend prolly just the biggest hotdog u can fit ya can get them upto 2 ft long just double check that it will fit and make sure u consider ur diameter while ur measuring...
also if u have a good triflow muffler they are very good as far as i can tell, i would assume that they flow pretty good and a good for noise reduction in the right application... if that is a good triflow muffler it will have glass pack in it and it wont be visible from the outlet u would have to check the manufacturer specs.

once again hope that helps man
jeremy

[Dutchy]

hey i just dug up some pics of exhaust parts i used, prolly useless to ya but i thought they were cool hehe :D
the big part in the first foto i didnt use... only the tip the rest was s#!t!

http://www.astinagt.com/forums/vbpgimage.php?do=full&p=2260&d=1193148299

The cats insides!
http://www.astinagt.com/forums/vbpgimage.php?do=full&p=2257&d=1193148248

The hotdog
http://www.astinagt.com/forums/vbpgimage.php?do=full&p=2258&d=1193148268

inside the hotdog
http://www.astinagt.com/forums/vbpgimage.php?do=full&p=2259&d=1193148285

Jeremy

[FEM]

well. i think its a super cat triflow.

the exhaust, yes, i agree, is too big for the application. i will soon be getting a vf12 and a nice intercooler to go with it. when andrew, greg and myself were discussing exhaust sizes, they suggested that the 2.5" is a much better option for the application. i insisted a 3" for the future plans of the application - vf12 or a gt30 series. i have no actuator on at the moment, boost is stock.. 7.1 or whatever and i still manage to hit cut which is set at 12psi

boost creep is very much a results of the zorst size. My exhaust was/is VERY high flow. Having no cat, a straight through reso, and a open cannon.. there was almost nothing stopping gasses from flowing through.

i forgot what i was going to say :(

dammit

DAMMIT

i will remember in the morning im sure.. off to bed

talk tomoro

dan

[FEM]

thanks for the pics man!! they are really useful

ahh so content that someones feels my pain about the drone issue :D

[LordWorm]

Dan,

you should be able to find a page somewhere that will calculate the resonance of mild steel at a given temperature for a given length - i haven't seen one, but i'm sure it'll be out there somewhere.... that'll get you in the ball park.

For the record though - i sat in your car for a relatively long drive and didn't hear the exhaust once... is the silencer still in?

If its loud in the back (unbareably) i'd suggest some dynamat... its going to be far easier to sound proof the car than it is to much around with resonance.

[FEM]

I go sound proofing in there ahaha.

Twigs car is a monster when it comes to sound! you have the mounts and the exhaust to deal with ahaha.

Its the drone when in a certain range.. its more like a vibration actually.

[Rupewrecht]

Thread cleaned up.

[RedLineResident]

Thread cleaned up.


what does that mean??

I am actuallym finding this thread quiet interesting o follow. I like the topic, its fuscinating.

[Rupewrecht]

Just some unnecessary personal attacks, which have been removed.

[FEM]

prolly needed to be cleaned, newman woulda cracked the sh!ts at me..

[Clarky_BA]

dynamat only does so much, and personally I think it is best for the audio boys and not the drone. I have my car fully lined, even went as far as to stick a sheet on the upper side of the exhaust. I have a lukey triflow and it only drones at specific rev ranges mainly 500rpm through to 6000rpm... And it can be unbearable. Went to the exhaust shop and said can I get a cat, they looked and I have two already. However after reading this I am going to order a lukey hiflow cat and see if that helps. Like you I dont want to lose the exhaust the car sounds too dam good with it.

[project.r.racing]

i'm gonna agree with dan with this one. get a bigger cat asap... meow!
i have a BP-05 engine and they are louder and crazier than BP-26 engines. when i replaced my cat with a bigger high flow version, nearly all drone was gone and it sounded better, had more power and responce. there was no negatives to doing this.

ryan

[FEM]

hmm, no drone?

i covered the tip the other day with some car board and is was SILENT, it could still flow too! i rekin a smaller tip ftw!

[bourbon]

hmmm wtf you mean you covered it???

[DavoAust]

he put some cardboard over the tip to make the effective size smaller. that would take any noise the tip is contributing up in frequency, eliminating the low bassy drone

[Clarky_BA]

I am going to try this tonight. I have a big oval tip, ford rx8 tip. Interested to see if it makes a difference. If it works I wonder if going to a dual tip would be better than a single big one. To stop any questions what I mean is instead of have a O tip I would put in an OO tip, or maybe an □□ tip.

[bourbon]

or even "oo" "ΔΔ"

[FEM]

hmm... that is interestiing.. i think i got a 4.5" tip atm on a TRR can muffler thing.. i covered the tip and it was silent, so i am going to get a 2 or 2.25" tip tomoro.. what u think?

[bourbon]

I THINK it will look girly!! you could even get a LOVE heart put on the end tooo!!! hahahahahaahahaha

[Rupewrecht]

Nah, get a Hello Kitty one. :p

No wonder you've got a drone with a 4.5" drainpipe on the back! Definitely get a smaller tip.

[FEM]

what about 2 tips..?

hahahah, love heart FTL!! i dont care what people think of my zorst..

[DavoAust]

dude get 2 shiny 2.25" tips. it'll look good and should cut down on the noise

[bourbon]

well if you dont care get a love heart one... prove to usyou dont care what we think :p hahaha

[FEM]

where do i get one !!! ???

ill try the one tip for the minute...
what about reducing in the middle of the zorst to a a 2.5 with 2 reso0nators?

[bourbon]

goto right price exhaust and mufflers near my work... corner of moss st and herbert st...

[Putonyourshoes]

http://tbn0.google.com/images?q=tbn:pgoLyaPodY96pM:http://www.carpartsforpimping.co.uk/acatalog/love-heart-tail-pipe.jpg

something like that mate?
decent tip nice shape
and its red:)
BAHAHAHAHAHa

[FEM]

YES! i want one hahahahhahahaha!!

red goes faster, dont ever for get it ;)

[Putonyourshoes]

hahahahahaha that one doesnt actually look too bad. ive seen a few that i would rather scratch my eyes out than put on my car

[FEM]

hahahahhahaah yeah yeah i agree!

ok, back to business... 2" dump tomoro, what do you think eh? will it shut my car up? and what about the reducer to 2.5" and two resos then back to three inch?

[Putonyourshoes]

i recon just change to a 3 inch tip... to be honest... there is no point IMO to make it overly complicated..
but then again.. i dont have a turbo car..
but i do suffer from the drone from a 4" tip...
i think.. high flow cat..2" dump.. a slightly bigger resonator.. and some insulation.. i think that should shut it up...
hahaha

[FEM]

wwell i got sound deadener in the boot. i will get a 3 inch cat
and a 2" dump tip?

[newman]

i think you really need to trial and error. lots of things have been suggested and i think you just need to try them rather than looking for even more suggestions.

[FEM]

no point changing my WHOLE system to a 2.5" or 2.25" if it *might* be loud still. i think its best to ask people what they thing before going and doing silly things when sometimes, they are not needed!

[DavoAust]

i'm gonna assume you can have the tip taken off your system without much trouble right? get a 2.5" tip on there, see if it still drones and annoys you. no point spending all that cash if you may be able to fix it with a tip change

[Clarky_BA]

This is what I did last night, got some cardboard and rolled it into a tube. Stuck it in the exhaust (not just hanging out of the tip but into the tip and into the actual exhaust), sat in the car and idled. The difference was amazing (yeah okay went around the block as well, could not resist it), thanks guys you potentially just saved me a couple of hundred dollars. I am getting on ebay to find me a nice purple love heart tip or two small ones... now that would be cool.

[FEM]

would two small ones be goodsom?

[Clarky_BA]

If you want to wait a week or two I will let you know. I do 140km a day in my car and the drone is killing me. So will get a new tip rather quickly, but from the test last night it is looking positive. To go even further getting tips with a slight bend to point to the road may help a bit as well. Will check it out and let you know.

[FEM]

what about a 3" dump and 2 crush bent stock systems?

[323kid]

lol crush bend??
may as well chuck ya stock exhaust system on
bad bad

keep your 3" system make it like this

turbo>>3" dump>>resonator>>cat>>muff
should keep things quiet dan

offtopic::
my cefiro will have, 3"dump>>3"pipes>>"HIGHFLOWCAT">>3" straightpipes
http://i160.photobucket.com/albums/t168/ilikeoreo/BecquetsZorst.jpg

feel the rb luuurrvvee

[FEM]

geeeze, that is a nice system ryan

isnt that zorst system going to be hell loud though?

[FEM]

ok,

after 2 weeks of researching i have come to the conclusion that i will change to a 2.5" from cat back with a xforce cat, resy and a VAREX muffler at the rear!

that! should shut it upp !!

[Putonyourshoes]

the carex itself would do a fair bit from what ive heard?:)
but let us all know how it turns out

[FEM]

will do

[bluesky_astina]

ok,

after 2 weeks of researching i have come to the conclusion that i will change to a 2.5" from cat back with a xforce cat, resy and a VAREX muffler at the rear!

that! should shut it upp !!

How did it turn out? quiet or what?