Emissions test/Exhaust noise level

by **160** » 11 Feb 2004 14:17

If you were going to run a Challenger with a straight through exhaust, i.e. no catalytic converter would that be a problem? How does it work with the emissions test when you MOT your car?

by **dave-r** » 11 Feb 2004 14:53

Challengers are too old to have a catalytic converter. These came out much later. Cars this old only have to pass a visual test in the UK.

i.e. If it looks smokey or makes the MOT guys eyes water it will fail.

If you really mean a 'straight through' exhaust (no silencers) then you might get a pull from the Police for making a noise although as far as I know there is not an actual law against running an open exhaust in the UK - just a defective exhaust.

However they might try to get you for 'causing a disturbance' or something.

by **160** » 11 Feb 2004 15:37

Thanks Dave. I was wondering about the catalytic converter issue as a guy at work thought I would have to put a cat on to pass the MOT and it didn't matter how old the car was. I thought that as it was a 1970 it would be exempt - now I know.

The straight through part is because I Was talking to Trevor about his 1970 WSS last night and I remember him saying the exhaust was a straight through. Probably just me getting it wrong though! :oops:

by **dave-r** » 11 Feb 2004 15:51

Nah. He has silencers on it. You can hardly hear it next to mine! :roll:

by **dave-r** » 12 Feb 2004 9:47

Out of interest I asked a UK traffic cop I know (who is a Challenger and Aussie Charger owner) about where the UK Police stand on the issue of a loud exhaust.

He said "the law says a vehicle must have a silencer fitted" . But there are "NO regs on size or decibel rating etc."

"MOT wise , a car must (for the test) not sound unreasonalbly loud for that type of vehicle."

This is subjective of course. But it means that the young lads in their modern cars with 5" exhaust pipes are going to have a tougher time than a 440 Challenger with a 3" exhaust. Because the modern car would normally be quiet and you could argue that a 440 Chalenger is never going to be quiet.

He went on to say;

"The other offence is "excessive noise" which is again down to the opinion of the person at the time, there is no set decibel limit."

...and...

"There is also a public order offence of noise causing nuisance (cant remember the exact wording) where there are powers to seize the offending vehicles!!"

He sumed up by saying "I tend to work on the no silencer fitted is the offence and not the excess noise, unless it is really bad and there have been complaints."

So there you go. Remember that this is one police officers opinion and other officers might see things different. But at least you now know how to play this if any of you ever get stopped.

I would be interested how the law stands in other countries if anyone wants to add to this thread?

by **Christer** » 12 Feb 2004 14:56

About testing the noise level: During test drive (at the swedish MOT) the inspection man simply opens the door and floor the gas pedal. (without any gear in) If he thinks that the car is too noisy, you will have to correct this and come back.
(BTW, this has happened to me once. I got to come back)

I think that there is an exact upper limit (in dB) when it comes to noice, but as they do not have any test equipment, they do have to use their own judgement.

by **dave-r** » 12 Feb 2004 15:48

So you need to find a very old inspector that is hard of hearing! :wink:

by **Christer** » 12 Feb 2004 19:10

...or you can use a set of turbo-mufflers. In my youth, I used the straight-through type of mufflers. They are

but can become a bit annoying in the long run.

by **dave-r** » 12 Feb 2004 22:20

You're just getting old Christer! :wink:

by **Christer** » 13 Feb 2004 5:56

I guess you are right. Although, since I am a Challenger-owner, I do it with pride :!:

It is quite fun to show the kids what a real car looks like

I forgot to mention one important thing. I used the straight-through type on a four-banger. Do I need to say more...? In short: A V8 engine makes music and a four-banger makes noice!? :lol:

by **ted** » 18 Feb 2004 20:58

1975 WAS first year for cats.

by **Tim** » 19 Feb 2004 15:16

This is a big relief to me. I've always worried about getting pulled for being 'silencer challenged'. I've got two cherry bombs on my exhaust system, and you could drop a billiard ball throught the middle of each of them. :twisted:

Did there used to be a theoretical MOT measurement in the UK, based around the Db level not exceeding a certain upper limit when measured 6ft from the car? As you say, it all comes down to the tester (I found one with a hearing aid and a glass eye) because none of them have got the kit to test your noise level properly.

by **dave-r** » 19 Feb 2004 15:23

I have never known of any db test done at MOT.

by **Lord Gryphon** » 30 Mar 2004 9:00

In Norway there is an upper limit on the noise. some where around 80-90 dB. I think it's 82dB but i'm not sure...

Re: Emissions test