I used to have a car with a competition rally system on, passed a few MOTs like that, but it had two absorbtion silencers and 2" bore pipe and 4-2-1 manifold
 
So they do use db meters then:D I can just imagine what the boss would say if the all garage work stopped so the MOT tester could get an accurate meter reading.

If he found my vehicles to loud, the first thing I would say is your meter calibrated like mine. I had to buy six but we only had 5 engineers at the time, so I kept one, and used when I stepped in with commissioning of a fire alarm system... no engineers spare to do the job.:(

Out of interest I’ll be checking the exhaust dB on my cars next weekend. Sound system in the disco peaks at 91db without distortion.

Aye he uses a DB meter when possible..

There is a large compound outside that he usually moves the car out to!

Nice and quiet ;)
 
There is some good info on here.
I asked the question only because I've cut and installed these valves on friend's '07 Mustang GT in Germany and '63 Chevy Impala in Arizona with no problems from the German TUV inspection, smog inspection or from the police.
 
I myself like a good V8 rumble, however there is a limit.

Unreasonably loud pipes just sound dickish to me, especially those on crummy little hatchbacks.

Although I don't discriminate any car with an overly loud exhaust should be failed imo.
 
I myself like a good V8 rumble, however there is a limit.

Unreasonably loud pipes just sound dickish to me, especially those on crummy little hatchbacks.

Although I don't discriminate any car with an overly loud exhaust should be failed imo.
How many v8 hatchbacks are there?
 
I myself like a good V8 rumble, however there is a limit.

Unreasonably loud pipes just sound dickish to me, especially those on crummy little hatchbacks.

Although I don't discriminate any car with an overly loud exhaust should be failed imo.

 
There are no db meters approved for MOT testing,

There’s no dB meters approved for testing life-safety systems either, but there’s a legal requirement that the meters are used and the results meet the requirements and are logged.
 
all MOT testing equipment needs to be of the approved type/specification........there are no approved db meters for MOT testing .......so officially cannot be used
 
all MOT testing equipment needs to be of the approved type/specification........there are no approved db meters for MOT testing .......so officially cannot be used

It appears the standard is entirely subjective and up to the judgement of the tester.


8.1 Noise
8.1.1 Noise suppression system
You must inspect:
  • exhaust silencers
  • under-bonnet noise deadening material fitted as original equipment – you don't need to inspect this for Class 3 vehicles
You must use your judgement to assess exhaust noise:
  • during the emissions test for the vehicle
  • rev the engine to around 2,500rpm or half the maximum engine speed if this is lower on vehicles not subject to an emissions test
Exhaust noise from the vehicle must not be unreasonably above the noise level you'd expect from a similar vehicle with a standard silencer in average condition.
 
all MOT testing equipment needs to be of the approved type/specification........there are no approved db meters for MOT testing .......so officially cannot be used

Simples, if it was a requirement... just state it meets the also requirements for use in checking exhaust sound levels in the meter’s specification, but then sound is sound wherever and professional meters are already certified and calibrated.

So what do u think would change with a dB meter? if there was a change to the MOT and exhaust sound levels were in included.

Perhaps to save holding it, it wouldn’t be a hand held meter, it would have a stand similar to a head lamp beam unit with a tape measure attached of course, to help the poor tester, as they will have a bit more to do, and so ensure that they have the correct distance from the exhaust pipe exit before carrying out the test.
We will see maybe or maybe not.:)
 
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Acoustics is a complicated science. You could have the best sound level meter in the world but it would give different results in different garages for the same car because the garage itself may be amplifying the sound level, not to mention all of the background noise the meter will pick up. I have several meters, the most expensive cost £1500, even when calibrated they don't always give the same result.

Col
 
If in the work place (which a MOT centre is) then noise becomes magistrates, or at least protecting staff from it does.
And further to what @JohnM70 sed, my red campers motor pipes engine sound through the bulkhead. Sounds great in the motor but no much noise out side.
 

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