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Vehicle Noise Limits
Posted: Fri Jan 28, 2011 1:19 pm
by Crazy_C
There have been many posts and bits of information and rumours of car noise levels.
I have been in a lengthy discussion with an engineer for the DfT and I have the full information here:
http://www.unece.org/trans/main/wp29/wp ... 051r1e.pdf
The limits are stated on page 10 and the testing method is in annex 3 found on page 20.
These are the maximum permissible limits for your car. If it exceeds this then you are breaking the law. Your car may be manufactured with a lower noise level than stated. In this case, the manufactured noise level will be the maximum permissible. So if your car was made producing 70dB on the test, this is what it cannot exceed.
This is 100% correct, accurate information as of the time of posting.
Posted: Sat Jan 29, 2011 2:30 pm
by Macaroon
So, I'm pretty much screwed come my next MOT then? Joy!
Re: Vehicle Noise Limits
Posted: Sat Jan 29, 2011 4:38 pm
by Pushki
If you're screwed Macaroon then so am I. I have the same exhaust system as you.
From what I understand, the Fujitsubo is 2dB quieter than the stock exhaust.
I'm not overly worried.

Posted: Sat Jan 29, 2011 4:41 pm
by Macaroon
Quieter? Really???????
So why do I feel like a ned everytime I put my foot down?

Posted: Sat Jan 29, 2011 6:58 pm
by nitin_s1
I have a plan! If police stop me saying that it's too loud I'm just gona say it's a Honda Access Muffler fitted from factory in Japan.

Because I know they had the option, it looks similar to what i have now and it's meant to be louder then OEM.

(Hopefully good enough excuse)

Posted: Sun Jan 30, 2011 12:29 am
by Crazy_C
Nitin, that makes no difference. I could have a factory fit exhaust, and be over the limit, still be illegal.
But if you read through it, the test is done on a 20m stretch, accelerating from 50km/h (approx 30mph) in a set gear (3rd I think, can't remember, I only paid attention to the auto bit) and the dB meter is midpoint along this 20m section, 7.5m to one side.
74dB from 7.5m away, when your car will probably be doing no more than 1200rpm anyways, should be an easy pass.
Though I was also told there's only 2 test sites at the moment that meet the requirement - Bedford and Nuneaton

Posted: Sun Jan 30, 2011 1:44 am
by nitin_s1
Crazy_C wrote:Nitin, that makes no difference. I could have a factory fit exhaust, and be over the limit, still be illegal.
So what about cars like Ferraris they have an OEM LOUD exhaust!

Posted: Sun Jan 30, 2011 2:51 pm
by Crazy_C
They will be set up so that when doing this test, they won't go over the noise limit, remember the test is done accelerating from 50km/h (30mph approx) so most higher powered cars will only be just off tickover really. Try it, 3rd gear at 30mph, how loud is your car?
A mate of mine did this test on his BMW M3 with a decat and it only registered 64dB.
Don't forget as well that the dB meter is 7.5m away. My old exhaust on the 940 was 122.9dB from about 1m away, but moving nearer or further will increase or decrease the apparent volume of it.
Posted: Sun Jan 30, 2011 3:08 pm
by nitin_s1
Oh i get it now, my car is really quite like that so I guess it will pass!
