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Pugme
05-06-2013, 11:51 AM
Can someone tell me there actual purpose please?

have a full 3" exhaust with a 4" japcan at the back, decatted and 2.5" to 3" downpipes.

contemplating removing either one or both the resonators, iv been told the leggy already pops little flames and is reasonably loud.

ats peoples opinions?

Davezj
05-06-2013, 01:27 PM
I believe a resonator and a muffler/silencer are designed to do the same thing.
quiet cown the exhaust noise.
resonator has a perfurated tube running straight through it the same size as the exhaust pipe, round the outside is a chamber full of sound energy absorbing material. which does the changing of the noise the exhaust makes to tune the sound it also makes it a little bit quieter. i presume that is why they are called resonators

a muffler/silencer on the other hand has an entry and exit point, not connected by a straight pipe, but more like a maze of baffles and sound absorbing wadding that the exhaust gases pass through to get out the other side. this absorbes much more sound energy and quiets down the noise a lot more than a resonator do.
i always think of the muffler/silencer as a volume conrtol and the resonators as the Tone control.
well that is how it was explained to me.

i could be wrong though.

Nick Mann
05-06-2013, 08:54 PM
That's my understanding too. Removing the resonators will make the car louder.

Pugme
06-06-2013, 04:52 PM
Sweet, well all or nothing, ill have them both out on saturday, should be interesting

fassi1
06-06-2013, 05:39 PM
Everything will depend on back box and tail pipe design, straight through pipes without resonators can be reasonably quiet.
If you don't want to make it loud go for biggest possible back box (oval back box) and tail pipe diameter as close as possible to back box clearance which I guess will be 3",
double skin tail pipe with perforated tube inside packed with exhaust wool (e-glass) will help to make exhaust quieter.

Kenneth
08-06-2013, 02:02 AM
Resonance is a bit different to exhaust volume (in dB). A back-box will affect the resonance somewhat, but mostly the exhaust note and volume is changed at the tip.

At some frequency, a thin walled tube of a certain length will resonate (same principle as a pipe organ) at which point it makes a hell of a noise. However this noise isn't necessarily heard at the tail pipe and due to the exhaust tunnel, it is usually transmitted into the ground and into the metal of the vehicle, causing what is commonly referred to as drone.
Resonators are used to move the resonance frequency out of normal cruising RPM/Load so that your ears don't feel like they are going to bleed.

Because the resonant frequency of the exhaust is determined by a number of factors, it isn't always easy to determine when it is going to occur. If you remove the resonators, you may find that the drone is un-bearable and you need to put at least one back in.

We did some testing a couple of years back when they changed the laws here in NZ to have dB limits to exhausts. It was quite interesting that the exhaust which sounded the loudest in the car (drone was pretty nasty) was not the loudest in dB, in fact it passed the noise test where one which seemed much more civilised failed. Of course the sound levels were measure from the tail pipe, not inside the car.

exevoowner
10-06-2013, 11:53 AM
Pugme how did you get on with your exhaust im thinking of just changing the rear can to see what diffrance it makes

HPRULZ
10-06-2013, 01:03 PM
At some frequency, a thin walled tube of a certain length will resonate (same principle as a pipe organ) at which point it makes a hell of a noise. However this noise isn't necessarily heard at the tail pipe and due to the exhaust tunnel, it is usually transmitted into the ground and into the metal of the vehicle, causing what is commonly referred to as drone.
Resonators are used to move the resonance frequency out of normal cruising RPM/Load so that your ears don't feel like they are going to bleed.

Because the resonant frequency of the exhaust is determined by a number of factors, it isn't always easy to determine when it is going to occur. If you remove the resonators, you may find that the drone is un-bearable and you need to put at least one back in.

.
Totally agree with Kenneth on this one I took my 3" stainless system off because the constant drone when cruising (even with extra sound insulation) was doing my head in! the system I got from Atik with multiple resonators in it is way better when cruising.

Kev

Pugme
10-06-2013, 01:57 PM
Well im now on a full straight thru system and it sounds awesome!

We

It was loud anyway, as my backbox is just a straight thru jap can, but id say the note to the car has got throatier it has a much deeper rumble now when in coming along, ill have to do a video or get my housemate to film it from the outside.

we were gonna swap his ssqv onto mine and put my r2d2 on his anyway so will do it then.

exevoowner
10-06-2013, 02:36 PM
have had a look around and was thinking of getting one of these 62764

pezza
10-06-2013, 05:21 PM
They do work Nigel, Kris made one up for his car and I was quite surprised how much of the exhaust resonance is a result of the single skinned tailpipe itself. Kris went a bit further and wrapped the perforated tube with steel wool (stainless steel wool is best) and this muted the sound even more. The sound emitted is much smoother and it knocked a few dBs off the volume.

adaxo
10-06-2013, 07:11 PM
have had a look around and was thinking of getting one of these 62764

where did you find it? as I get some complains about my 101 db exhaust noise

exevoowner
10-06-2013, 09:38 PM
adaxo there on flea bay bout £20 i think it was

fassi1
10-06-2013, 11:07 PM
The only thing is that it will restrict exhaust system slightly.

pezza
11-06-2013, 11:34 AM
where did you find it? as I get some complains about my 101 db exhaust noise

101??? err