dr-fastlane
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 posted on 4/3/05 at 04:56 PM |
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To much noise
To satisfy to the Dutch legislation, the noise of my car can not come above 77 dBA. And that seems to be a big problem.
Which (bike) silencer do you think i most use??? And has someone a photograph how decibel-eaters (or how it is called) look like??
Thanks!
P.S. Ideas how to build a low-noise silencer are also welcome.
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I have not failed once. I have successfully found ways that will not work!
https://www.motor-forum.nl/threads/hardtail-dragstyle-project.343482/
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DarrenW
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| posted on 4/3/05 at 05:00 PM |
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What engine / exhaust are you using.
It sounds like you will have to build fairly close to OEM std and then maybe modify later (unless it will be checked every year).
What do Donkervoort do?
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Jon Ison
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| posted on 4/3/05 at 05:08 PM |
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can you get the car over here, sva and register it then inport it back ? would that get around the noise, i ask cos i see lots of Dutch cars going
thru Mk every week?
The starter motor will make more than 77Dba, that seems very low.
how do Dutch bikes go on ? surley they cant get under that noise level can they ?
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alister667
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| posted on 4/3/05 at 08:02 PM |
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I'd double check that 77dBA figure.
As Jon says that is very quiet. Perhaps they measure it on tick over?
Anyhow ways of reducign noise include some acoustic foam on the underside of the bonnet. I got about £20s worth from Europa did my bonnet and you can
hear a noticable difference, espec with induction noise.
Also you can fit a coupl of stainless steel pot scrubbers (looks like stainless steel 'curls' all coiled together - no soap remember!) in
the exhaust in front of the silencer, they wil knock off a few dB. Of course they can easily 'fall out' later.....
http://members.lycos.co.uk/alister667/
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JoelP
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| posted on 4/3/05 at 09:51 PM |
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77dbs is a ridiculous target, i snore louder than that... comiserations if that is the actual target, you've got no chance!
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Simon
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| posted on 5/3/05 at 01:12 AM |
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According to Braniac: Science Abuse the other night a neumatic drill was 119db, and a screaming baby......
123db
ATB
Simon
[Edited on 5/3/05 by Simon]
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scutter
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| posted on 5/3/05 at 07:58 AM |
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123db is that all.
ATB Dan a tired dad
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NS Dev
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| posted on 5/3/05 at 09:41 AM |
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Surely not 77dBA!!!!!!!!!
That is bordering on silence!
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dr-fastlane
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| posted on 5/3/05 at 10:07 AM |
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DarrenW: The engine which I use is a 2.0 injected pinto engine. This quiet exhaust is only to get the car on the road, i modefy it later.
Donkervoort uses a stainles steel exhaust that is very very expensive! And normally they do not sell that to people who themselves drive no
Donkervoort. And they are not secondhands to buy.
Jon Ison: To get the car over there would be a better plan. But my English is very bad (Hoera for the translation sites on the internet!!!).
I think that those 77 dBA ar a sort of target. Most bikes make more noise, donkervoort also.
When i try to get the sound level as low as possible. Ik think that they will not do so difficult and accept it.
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I have not failed once. I have successfully found ways that will not work!
https://www.motor-forum.nl/threads/hardtail-dragstyle-project.343482/
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paulf
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| posted on 5/3/05 at 11:17 AM |
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You could try taking the tailpipe back under the chassis like on some caterhams and then adding an extra silencer at the rear.My MGB box with some
extra packing added for SVA was quiet and measured 95db at test.Im sure a silencer with internal baffles such as from a sierra etc could be used.
Paul.
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dr-fastlane
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| posted on 5/3/05 at 11:51 AM |
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Paulf: The first option was to put an extra silencer at the rear. But if you can see in the topic:
http://www.locostbuilders.co.uk/viewthread.php?tid=22428
If got an problem with the fuel tank. I have made a exhaust from an vw golf catalytic converter and middy demper and at the rear an vw corrado rear
mufler. But is also noisy. I think a good bike silincer will do the job. If i only knew which
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I have not failed once. I have successfully found ways that will not work!
https://www.motor-forum.nl/threads/hardtail-dragstyle-project.343482/
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DarrenW
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| posted on 7/3/05 at 10:27 AM |
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dr-fastlane,
There are no problems with your written English. It is easier to understand than some Engish peoples emails! I think you would have more problems with
my Dutch!!!
If you want a custom made bike style can why not contact this person, he may be able to do something to fit your space.
http://www.locostbuilders.co.uk/viewthread.php?tid=19230
It sounds like 77dB is a rough target that you have to show that you have tried hard to achieve. Do you know anyone else with a similar car who has
passed slightly higher (i guess you wouldnt have asked if you knew someone in Holland you could ask though!). How is it checked - in England it is
checked at a known distance at 75% (??) of full power revs.
Once you have passed is that the last time you will be checked or do you also have a yearly test to pass as well? What about spot checks by Police
etc?
If it is a one time check im wondering if 907 could build a longer larger diameter side can that can be stuffed full with extra wadding to quieten it.
This will of course reduce power and possibly revs. If you quote full power at less than actual and max revs also lower, the engine will be at lower
revs for the test and hence also be quieter. Under bonnet insulation should help, im not sure if exhaust wrap may also dull the sound (any comments
anyone).
This might be a really daft idea - what about two side silencers, one above the other, just for the test. 2 pipes into the bottom one and other 2
pipes into the top on. Lots of wadding into each. This idea may not be practical but as with all good brainstorm ideas it may prompt a good solution.
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