Exhaust noise limit!
Discussion
There is no arbitrary limit in terms of decibels.
There is however the following legislation:
The Road Vehicles (Construction and Use) Regulations 1986
http://www.legislation.gov.uk/uksi/1986/1078/regul...
Short version: It is an offence to modify an exhaust system so as to generate more noise than it did from the factory. Obviously this is open to some intepretation, but unless you've got some way of proving that the car was type approved with the exhaust that is fitted (i.e. unmodified) then you're probably on a hiding to nothing.
There is however the following legislation:
The Road Vehicles (Construction and Use) Regulations 1986
http://www.legislation.gov.uk/uksi/1986/1078/regul...
Short version: It is an offence to modify an exhaust system so as to generate more noise than it did from the factory. Obviously this is open to some intepretation, but unless you've got some way of proving that the car was type approved with the exhaust that is fitted (i.e. unmodified) then you're probably on a hiding to nothing.
It depends on the age of the car but as far as I can tell it's anywhere between (for petrol cars) 74dB(A) (1996 - nowish http://eur-lex.europa.eu/legal-content/EN/TXT/?uri... ) and 82dB(A) (1978) measured on a drive by test approaching the meter at 50km/h in 2nd then flooring it.
There's a static test too, measured holding the engine at some highish revs then shutting the throttle, I've no idea where to look the numbers up for that for older cars but 1996-whenever the new limits come in it's 72dB(A).
There's all sorts of oddities in the regs that add on 1db or so for various things or reduce the speed at the test a bit but none of it gets anywhere near actually loud.
Since the number of cars that are going to be properly tested after being type approved is around about none at all you're looking at construction and use as linked to above which really comes down to whether or not you're taking the piss more than actual numbers.
There are tons of threads on here over the years about this, some full of useful information, http://www.pistonheads.com/gassing/topic.asp?h=0&a... has some sensible stuff in it.
There's a static test too, measured holding the engine at some highish revs then shutting the throttle, I've no idea where to look the numbers up for that for older cars but 1996-whenever the new limits come in it's 72dB(A).
There's all sorts of oddities in the regs that add on 1db or so for various things or reduce the speed at the test a bit but none of it gets anywhere near actually loud.
Since the number of cars that are going to be properly tested after being type approved is around about none at all you're looking at construction and use as linked to above which really comes down to whether or not you're taking the piss more than actual numbers.
There are tons of threads on here over the years about this, some full of useful information, http://www.pistonheads.com/gassing/topic.asp?h=0&a... has some sensible stuff in it.
zombeh said:
It depends on the age of the car but as far as I can tell it's anywhere between (for petrol cars) 74dB(A) (1996 - nowish http://eur-lex.europa.eu/legal-content/EN/TXT/?uri... ) and 82dB(A) (1978) measured on a drive by test approaching the meter at 50km/h in 2nd then flooring it.
I''m not sure the EU rules applied in the UK (the Aston Martin Vantage Le Mans had to be sold with the original shorter 'diff and 6 speeds in the 'box to pass the drive by rules when sold in some European countries). 
)Probably irrelevant but as a vehicle can fail an MoT for excessive noise I'll throw it into the pot.
No testing equipment used & it's the opinion of the tester:
'4. A silencer in such condition, or of such a type, that the noise emitted from the vehicle is clearly unreasonably above the level expected from a similar vehicle with a standard silencer in average condition.'
http://www.motuk.co.uk/manual_710.htm
ETA perhaps the OP could enlighten us on what's actually happened. Going on his username has he sold a system to a customer who's now having problems as a result of fitting it?
Possibly complaints from where/how a vehicle is being driven resulting in action for anti-social behavior?
No testing equipment used & it's the opinion of the tester:
'4. A silencer in such condition, or of such a type, that the noise emitted from the vehicle is clearly unreasonably above the level expected from a similar vehicle with a standard silencer in average condition.'
http://www.motuk.co.uk/manual_710.htm
ETA perhaps the OP could enlighten us on what's actually happened. Going on his username has he sold a system to a customer who's now having problems as a result of fitting it?
Possibly complaints from where/how a vehicle is being driven resulting in action for anti-social behavior?
Edited by paintman on Saturday 3rd December 08:48
Let's be fair here, the exhausts that usually get the attention of the Police hardly require a qualified sound engineer to know they are much louder than stock!
What I don't get is why they usually get fitted to cars that then sound so s
t!
Certain cars with loud exhausts sound fine (think TVR, Aston Martin, Ferrari, Jaguar, Subaru, American V8's, My old FIAT X1/9 with the ANSA exhaust, My workmates old E60 M5 with the sports exhaust fitted - It had a nice rumble at low speeds and sounded like an V10 F1 car when let off the leash!), but the cheap tin box Punto's, Corsa's, etc., etc, just sound bloody awful! - Tinny, raspy, and more often than not like someone having a wet fart!
Don't get Me wrong, I'm not some old fuddy-duddy when it comes to modifying cars - I followed an original shape mini Thursday morning that had a modified exhaust that was loud, and that little A-series engine sounded great!, I just don't get why certain people think having their car sound st but loud is so cool!
Perhaps the Police could add an extra offence:
1st Offence: Exhaust exceeds permitted noise levels.
2nd Offence: Exhaust sounds st!
What I don't get is why they usually get fitted to cars that then sound so s
t!Certain cars with loud exhausts sound fine (think TVR, Aston Martin, Ferrari, Jaguar, Subaru, American V8's, My old FIAT X1/9 with the ANSA exhaust, My workmates old E60 M5 with the sports exhaust fitted - It had a nice rumble at low speeds and sounded like an V10 F1 car when let off the leash!), but the cheap tin box Punto's, Corsa's, etc., etc, just sound bloody awful! - Tinny, raspy, and more often than not like someone having a wet fart!
Don't get Me wrong, I'm not some old fuddy-duddy when it comes to modifying cars - I followed an original shape mini Thursday morning that had a modified exhaust that was loud, and that little A-series engine sounded great!, I just don't get why certain people think having their car sound s
t but loud is so cool! Perhaps the Police could add an extra offence:
1st Offence: Exhaust exceeds permitted noise levels.
2nd Offence: Exhaust sounds s
t! [quote=paintman]Probably irrelevant but as a vehicle can fail an MoT for excessive noise I'll throw it into the pot.
No testing equipment used & it's the opinion of the tester:
'4. A silencer in such condition, or of such a type, that the noise emitted from the vehicle is clearly unreasonably above the level expected from a similar vehicle with a standard silencer in average condition.'
http://www.motuk.co.uk/manual_710.htm
Many years ago in a garage I worked we had a customer with a company Morris Ital stopped by the police and given a ticket for a noisy exhaust. We checked the car and could find nothing wrong with the exhaust it was just a standard aftermarket replacement by one of the exhaust centres with a slight rasp, on phoning his boss we were told just to replace the system which we did, the driver wasnt happy as he wanted to argue the point with the police.
A week or so later I was on a MOT refresher course and brought up this case with the vehicle examiner running the course and have yet to get a straight answer. My scenario was a RS2000 rally car with a competition exhaust, much louder than would be expected from a standard road going car with a standard exhaust but not louder than you would expect from a competition prepared car which still requires an MOT test, all i got in reply was if I failed the next comp prepared car I tested for excessive noise he would do the appeal, still didnt give an answer as to whether he would back me up or condemn me.
No testing equipment used & it's the opinion of the tester:
'4. A silencer in such condition, or of such a type, that the noise emitted from the vehicle is clearly unreasonably above the level expected from a similar vehicle with a standard silencer in average condition.'
http://www.motuk.co.uk/manual_710.htm
Many years ago in a garage I worked we had a customer with a company Morris Ital stopped by the police and given a ticket for a noisy exhaust. We checked the car and could find nothing wrong with the exhaust it was just a standard aftermarket replacement by one of the exhaust centres with a slight rasp, on phoning his boss we were told just to replace the system which we did, the driver wasnt happy as he wanted to argue the point with the police.
A week or so later I was on a MOT refresher course and brought up this case with the vehicle examiner running the course and have yet to get a straight answer. My scenario was a RS2000 rally car with a competition exhaust, much louder than would be expected from a standard road going car with a standard exhaust but not louder than you would expect from a competition prepared car which still requires an MOT test, all i got in reply was if I failed the next comp prepared car I tested for excessive noise he would do the appeal, still didnt give an answer as to whether he would back me up or condemn me.
Don't disagree with that as long as things are done fairly. there is more control on bikes with exhaust labelling.
What I'm trying to ascertain is the point of law that a police officer is calling upon when using a sound meter to issue a ticket, , and how the test process is proven. If the vehicle was in front of a race sound test the rules would be clear
What I'm trying to ascertain is the point of law that a police officer is calling upon when using a sound meter to issue a ticket, , and how the test process is proven. If the vehicle was in front of a race sound test the rules would be clear
Well there is a measure that was used. My Westfield passed the SVA at 101 DB which was the maximum then. Under the new IVA it is reduced to 98DB so by that my car which is not quiet as measured at 3/4 maximum revs is legal and an MOT fail if it was less than that would be challenged.
That is the issue where you have "opinion" of an officer being the measured, it cannot be right when you have fully complied with the Law at the time of manufacture.
I think this is aimed at the "chav" type cars where a drain pipe is used instead of a silencer but as normal it then creeps into other areas.
That is the issue where you have "opinion" of an officer being the measured, it cannot be right when you have fully complied with the Law at the time of manufacture.
I think this is aimed at the "chav" type cars where a drain pipe is used instead of a silencer but as normal it then creeps into other areas.
I have vague recollection of a thread where a chap had an aftermarket exhaust and got some sort of FPN or equivalent, but was taking it to court on the basis that the policeman who stopped him didn't follow procedure (possibly as there wasn't actually a clear one to follow!)
This was on the basis that the car was louder than factory standard.
This was on the basis that the car was louder than factory standard.
I think if you're building a car from scratch then you can look for the requirements of the SVA/IVA whatever it is test. If you're modifying an exhaust then you just need to make sure it doesn't make any more noise than when new.
The police are clearly not inclined to spend time on the issue but occasionally when pushed some police forces have to deal with a noisy bunch and when they do they seem to have adopted a very generous 82 dbA limit and even then don't prosecute until exceeding 90. I think they don't take it too seriously as they expect the lads to grow out of it soon enough. As far as I can see they generally follow an ISO procedure ISO 5130 which specifies meter locations and rpm but not the threshold value. I don't know where the 82 comes from but I wonder if it has been carried forward from an earlier age prior to the EU drive by testing. It's certainly generous for modern cars.
The police are clearly not inclined to spend time on the issue but occasionally when pushed some police forces have to deal with a noisy bunch and when they do they seem to have adopted a very generous 82 dbA limit and even then don't prosecute until exceeding 90. I think they don't take it too seriously as they expect the lads to grow out of it soon enough. As far as I can see they generally follow an ISO procedure ISO 5130 which specifies meter locations and rpm but not the threshold value. I don't know where the 82 comes from but I wonder if it has been carried forward from an earlier age prior to the EU drive by testing. It's certainly generous for modern cars.
simoid said:
I have vague recollection of a thread where a chap had an aftermarket exhaust and got some sort of FPN or equivalent, but was taking it to court on the basis that the policeman who stopped him didn't follow procedure (possibly as there wasn't actually a clear one to follow!)
This was on the basis that the car was louder than factory standard.
I was thinking the exact same thing.This was on the basis that the car was louder than factory standard.
I wonder if the thread is around?
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
Can't remember what page the conclusion was, but basically the police made up thier own rules and somehow the guy was still found guilty but received an absolute discharge.
Can't remember what page the conclusion was, but basically the police made up thier own rules and somehow the guy was still found guilty but received an absolute discharge.
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