MOT Major Defect, Really?!?

robj20 said:
Or just get a properly designed system that is only loud at high revs.
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Well yes thats the other thing, i spent a shed load on this MX5 exhaust here sitting in my back room (too lazy to fit at the moment) as its properly designed and resonated.
But chavs will be chavs and fit stupid unsilence big bores to shopping carts all over the country.
 
On my motorbike I have removable baffles, leave them in for commuting and take them out for Sunday afternoon rides.
It is a bit obnoxious with them removed, but only at high revs, pulling out of the street they are fine.
 
this isn't a new test/fail criteria - it was certainly in since 2012 when the decat visual checks were added, and probably there before. But, it's worded was ambiguous from memory, something like "exhaust cannot be designed to be louder than a standard" - the present wording is here

I agree with the minority? - it's high time MOT testers clamped down on awful loud exhausts and full decats. Without anyone seeing the car, we don't know what's been modified - for all we know the resonator/silencer had been removed which would obviously make it undesirable to a lot of people.

I can't deny I've fitted sports exhausts in the past, but now I live slightly out of the city and see a few horses on the roads, all the popping and banging exhausts are a nightmare for them and can make it quite unsafe for any rider and anything near them, so my personal views have changed a bit.

from a quick google - it looks like there is a dB limit for car manufacturers, so I guess this is what should be checked at MOT (but I know MOT stations wouldn't have a dB gauge): http://www.dft.gov.uk/vca/fcb/cars-and-noise.asp. That suggests 74dB is the present limit yet track limits are often ~100dB static and ~90dB drive-by - so if anyone's modified car struggles to fail track limits (know of some mates that have moaned about this) then this surely suggests a 15-25dB increase from stock, which is a lot...
 
DereksDontRun said:
this isn't a new test/fail criteria - it was certainly in since 2012 when the decat visual checks were added, and probably there before. But, it's worded was ambiguous from memory, something like "exhaust cannot be designed to be louder than a standard" - the present wording is here

I agree with the minority? - it's high time MOT testers clamped down on awful loud exhausts and full decats. Without anyone seeing the car, we don't know what's been modified - for all we know the resonator/silencer had been removed which would obviously make it undesirable to a lot of people.

I can't deny I've fitted sports exhausts in the past, but now I live slightly out of the city and see a few horses on the roads, all the popping and banging exhausts are a nightmare for them and can make it quite unsafe for any rider and anything near them, so my personal views have changed a bit.

from a quick google - it looks like there is a dB limit for car manufacturers, so I guess this is what should be checked at MOT (but I know MOT stations wouldn't have a dB gauge): http://www.dft.gov.uk/vca/fcb/cars-and-noise.asp. That suggests 74dB is the present limit yet track limits are often ~100dB static and ~90dB drive-by - so if anyone's modified car struggles to fail track limits (know of some mates that have moaned about this) then this surely suggests a 15-25dB increase from stock, which is a lot...
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15-25db s massive!

DB is a logarithmic scale, 3db is a doubling in sound pressure level.
As the article points out, the difference between 82db and 74 db is that one car at 82db makes the same noise as 7 cars at 76db, so 15db is massive, 25db is quite insane increase

There used to be an exemption for super cars, they were allowed an extra couple of db (from memory) the definition was unclear i think, but obviously only a few cars such as prius would count ;)
 
sideways14a said:
Well yes thats the other thing, i spent a shed load on this MX5 exhaust here sitting in my back room (too lazy to fit at the moment) as its properly designed and resonated.
But chavs will be chavs and fit stupid unsilence big bores to shopping carts all over the country.
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The street my sister lives on had to complain about chavs with loud sheds driving by. They did actually clamp down on it.

It makes a difference what kind of car people are fitting "sporty" exhausts to as well. On some 1.2 chav mobile it just sounds flat and awful. On bigger and more powerful engines you get a low pitched tone which isn't annoying at low revs.
 
I worked with a guy who had an old Corsa with a stupid exhaust, he never had any MOT issues but his neighbours all did gang up on him and report him to the council. The police then put a lot of pressure on him with constant visits asking him when he was going to sort it out, he'd get pulled over at least once a week also. I suppose it didn't help we were on shifts that started at 4 / 5 / 6am. It would have annoyed me too.

To be fair to him they were really overstepping and they just made his motoring life so miserable that he just got rid of the car in the end.

Nowadays the police would probably say they don't have any resources.
 
Jamesyboyjim said:
I worked with a guy who had an old Corsa with a stupid exhaust, he never had any MOT issues but his neighbours all did gang up on him and report him to the council. The police then put a lot of pressure on him with constant visits asking him when he was going to sort it out, he'd get pulled over at least once a week also. I suppose it didn't help we were on shifts that started at 4 / 5 / 6am. It would have annoyed me too.

To be fair to him they were really overstepping and they just made his motoring life so miserable that he just got rid of the car in the end.

Nowadays the police would probably say they don't have any resources.
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Good on his neighbours. Should not have to put up with chavvy cars
 
Jamesyboyjim said:
I worked with a guy who had an old Corsa with a stupid exhaust, he never had any MOT issues but his neighbours all did gang up on him and report him to the council. The police then put a lot of pressure on him with constant visits asking him when he was going to sort it out, he'd get pulled over at least once a week also. I suppose it didn't help we were on shifts that started at 4 / 5 / 6am. It would have annoyed me too.

To be fair to him they were really overstepping and they just made his motoring life so miserable that he just got rid of the car in the end.

Nowadays the police would probably say they don't have any resources.
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Sounds iffy. They'd only have to hit him with a section 59 and bye bye car.
 
Maybe we should have regulations on exhaust sound in terms of taste :p . For example:

V8/V10/V12 = Enforce a minimum db.
V6/Boxer/Flat,Straight = Set max exhaust diameter, no db limit
IL4 = Set max exhaust diameter and enforce a maximum db.
2/3 Cyl = LOL
 
Mercenary Keyboard Warrior said:
15-25db s massive!
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yeah, i know it's massive, which is why i was v surprised when i considered the difference between track limits and that comment.

Looking at the EU regulation No 540/2014 there is a banding for bigger engines (so I guess the super car exemption you mentioned)

dB limit for engine size for the next few years:

rated engine power....2016....2022....2026
≤150kW ...................76........74.......73
150 to 250kW.............78........77.......76
>250kW.....................80........78.......77

This looks like it's measured at 0.5m from the exhaust tip, at 45° to one side, with throttle at 50%.

for ref, for a MOT test today, as 2016 cars are too new, the limits (set in 2007):
<75kW - 77dB
75 to 150kW - 78dB
>150kW - 80dB

But, I would imagine kit cars, or possibly small quantity, might be exempt? it's a 65 page pdf and i don't have the desire to self-harm enough to wade through it all...

so, with the way the MOT is worded - that it can't be louder than "standard" then surely the above dB values are a limit for cars produced post 2016. But, I would well imagine some cars are above this when stock...
 
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When I had a sports exhaust on a jap car, I had the bung in most of the time, and even then I would keep the revs down very low once in residential areas.

The bung usually only came out during "fun" drives, and I had gloves and tools in a the boot that meant I could re-add/remove it in a minute if needed.

It was obscene without the bung.
 
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