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MOT test to fail noisy cars


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Guest banjo_bob
Have you heard a vantage on wot?

 

I have, but they are built like that, so a similar vehicle with a silencer in average condition, will sound the same, hence complying with the MOT guidelines . Plus they have an electronic exhaust valve that opens at WOT, so the idle sound is pretty minimal.

 

Although the MOT rules don't say "in standard form" it's what it basically means I expect.

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Guest bleasem

ASOBs are relevant here but would only be used when other legal solutions have failed. The main regulations are the Road Vehicles Contstruction and Use Regulations 1986. Vehicle noise is covered here and is along the lines of 'exhausts systems must be contstructed with effective silencers and maintained and not modified to increase noise'. I understand that the maximum noise limited for cars is 74dB(A). For some reason some MOT centres are strict on this and others are not. Perhaps an MOT tester on here will be able to say why. I expect that this will be an area that the authorities may sharpen up on in the future and I have also read of the possibility of the vehicle inspectorate doing road side checks on noise levels, this seems to a way off at the moment due to the difficulties in obtaining an accurate sound level reading in a roadside environment.

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I've heard from the horses mouth that MOT test centres are being spot-checked for this now, and their operating license is at risk for passing cars that are unreasonably louder than stock. Everyone argues that "they can't prove it", but lets face it, it's obvious if a car is louder than what you might expect to be "stock".

 

Whether it is "unreasonably" louder is currently discretionary, but you can bet your arse that defined limits WILL be set in the near future - whether that is an arbitrary limit or a database of proper measurements for each vehicle type, or even just a volume measurement during testing which VOSA might double-check during a spot-check for exhausts being swapped for testing purposes...

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Seems 2 different points are being discussed here, what police can do - which is basically anything they want, and what an MOT station can do.

I would have thought if it is supposed to be coming in as a legislation that is to be supported then it has to be the same "standard" across all the MOT stations. You cant just have a MOT test for "Do you think it sounds too loud".

Would have to be comparable against a statutory amount (like the emissions test) brake test etc.

Know this dosnt apply to all garages like as some are "friendlier" than others but if some new law was coming in, should have something to measure with/against. - Same as why the traffic cops, to charge you with having an exhaust that is above the sound limit, have to have a reading of the db output of your car. Even the police have to have some form of evidence and comparison figure to work with.

Edited by d-_-b (see edit history)
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b;2250950']Same as why the traffic cops' date=' to charge you with having an exhaust that is above the sound limit, have to have a reading of the db output of your car. Even the police have to have some form of evidence and comparison figure to work with.[/quote']

 

That's not true actually. There is no fixed db limit for cars. The law says something vague along the same lines as the MOT guideline. The police can issue you a penalty notice or whatever which you could pay or take to court in which case they would have to argue that it was unsociably loud or something. There is no automatic law that says greater than Ndb is illegal.

 

There's lots of MOT things that are a bit subjective. Things like excessive play in ball joints - who says what excessive is? Or the fact your windscreen wipers have to clear the screen effectively.

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Cant you just put your baffles back in if you have them to make it quieter??

 

I know when i had my motorbikes that they had to have their baffles in otherwise they wouldnt pass, but honestly didnt know you could fail a car for it as well as mine passed ok :)

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That's not true actually. There is no fixed db limit for cars. The law says something vague along the same lines as the MOT guideline. The police can issue you a penalty notice or whatever which you could pay or take to court in which case they would have to argue that it was unsociably loud or something. There is no automatic law that says greater than Ndb is illegal.

 

There's lots of MOT things that are a bit subjective. Things like excessive play in ball joints - who says what excessive is? Or the fact your windscreen wipers have to clear the screen effectively.

 

For a car to pass the SVA it has to be under 97db. Bruntingthorpe had 97 imposed on it because of this reason.

 

A standard Supra is 74db, if yours is 120db then it's 15 times louder than a standard car, also we have to wear ear defenders at work with a 83db limit. 87bd and your employer has to give you a safe haven so you can take a break from the noise.

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For a car to pass the SVA it has to be under 97db. Bruntingthorpe had 97 imposed on it because of this reason.QUOTE]

 

The SVA was 102 dB when mine went through in 2000

 

Police here have had noise testing equipment for a couple of years, have had a few of the younger guys change their exhausts

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I'm doing a track day in my mr2 in April. I put a full blueflame system on as my cat was dead on mine. I'm going to buy a cat as i'm worried about being over the 100db for Castle Combe :( I wasn't told anything bar i'd need a cat for my mot when the garage fitted it and they are the guys that do it and that was last month :) So I think its the mot peeps discretion about noise etc!

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We are doing a track day tomorrow, limits static @ 3/4 max revs 101dbA, 20meter fly by at WOT 87.5dbA. The RB engoince car got through today at 84dbA static 85dbA fly by. We have managed to cut 20dbA.

 

I would imaging SVA limits would be what is seen as acceptable. They would have to add calibrated noise meters to every MOT station, as it is impossible to judge how loud something is with the human ear.

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For a car to pass the SVA it has to be under 97db. Bruntingthorpe had 97 imposed on it because of this reason.

 

The SVA is irrelevant though - there are lots of things in there that aren't in the MOT. That's why most kit cars are built to satisy the SVA and then immediately put back to "normal" roadworthy condition - they will still pass an MOT but not the SVA. Also the noise limits at work you are talking about are at the ear, it depends where you measure at. E.g. is it a metre from the exhaust at 45 degrees, right by the exhaust directly in line etc. That would make a huge difference. I guess that's why it's a subjective limit.

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Found out a little more about "mot rules regarding sound produced" a pic from the MOT testers update from VOSA:

 

image

 

I didn't take the picture myself someone from a local forum posted it after their brother in law (an MOT tester) got the new handbook through.

 

So if this is indeed correct, our cars will be tested volume wise based on a similar car with a standard backbox...??? Can anyone say discrimination.

Edited by d-_-b (see edit history)
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It is not practical or a good use of resources for the police to control things like that in widespread way, when they have so much else to do.

 

That MOT tester is a joker, there are some real characters who are MOT testers. Salt of the earth, talked to some today.

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  • 4 years later...
Has anyone heard of new mot legislation that will fail any car with a noisy exhaust ? dont know what decibel level constitutes noisy but this came from a guy who works in a testing station.Also talk of the boys in blue having a gun to register noise levels, is it all a wind up :(

 

mot test centres judge exhausts on the emission levels, not the noise level

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