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'Laws on exhaust'


CelicaRy

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Hi everyone, just a question about exhausts and the laws around them, after servicing my car and having an exhaust blow I got a new custom one put in, it is now obviously not standard and louder than the original, all declared on insurance, however what are the laws surrounding a loud exhaust etc. people have said it can fail mots for being too loud and you can get pulled over but most other forum posts on this go off into different answers and what not, has anyone got a definite answer for this?

Thanks!

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Quick! Everyone run for cover before Monkey Boy sees this post!

Sorry - what I mean is experts with a lot of practical experience will no doubt be along shortly to answer your question!

Edited by Askari
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If the plod think your exhaust is loud, the first thing it does is give them a reason to pull you and then have an excuse to have a closer look at your car, to see if they can pick you up on anything else. They can accuse you of exceeding 'noise level' which is around 82db I think, but the car has to be tested in an open space with the equipment at a set distance and the car at x amount of revs, However. .....there is a lot of legal ifs and buts around this, as mentioned our own Monkey boy had a prolonged case involving the exact wording, execution and indeed exact meaning of all this stuff..and he won.Mind you they also said the reason they pulled him was because his exhaust system 'looked loud', the idiots.

From an MOT point of view rightly or wrongly itll depend how strict the tester is.Even so, without being able to test the car to the above 'guidelines', can an MOT tester fail the car just because it sounds loud? if the system is sound and has no leaks etc, if theres a CAT fitted where it should be etc ? I think the regs state 'excessive noise' but who's the judge of that. Thats why you get a lot of different opinion on this; the regs are sort of there but they are still a bit wobbly if you take it all the way

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It depends on the tester it's partly down to their discretion. I took my old ss11 in twice and they failed it ended up putting a bung in to pass. Took it somewhere else the next time and they passed it no problem without the bung

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Iv had advisories before for "noisy exhaust" but it's down to discretion of the tester if he thinks it's excessively loud.

I think it's more common sense then anything, why people try and make the car as loud as possible is beyond me! Granted mines not exactly quiet but I can't really get it any quieter without sacrificing power!

There's a lad on my street with a 1.6 focus and his exhaust is a lot louder than mine but then again the 80 bhp or whatever it's got needs to breathe ;)

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I get an advisory sometimes and not others depending on which tester does the vert at the garage. But always with the comment, dont take any notice of that i love how this thing sounds and a ;)

Though the last policeman on hearing the rumble as i was trying not to draw attention pulling away from the lights i saw in my rear view mirror step out into the road and squat down with a wtf is on that look on his face :blink:

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hmm well i opted for a midrange exhaust from a custom shop and mine ticks all the boxes and isnt just a loud exhaust .... mine went through MOT a few weeks ago and mine was ok and thats had a year of wearing in so its deeper now and pops from time to time.. my brother drives a bloody loud citroen saxo 1.4 replica and that is just so loud im quite surprised it went through a MOT as i had to drive it back from swindon a few weeks ago because my bro had a knee op and i was just so glad to get it home and get the hell out lol ..no clarity of that exhaust.


i did ask neil at greenlight whether i needed to declare the 215 tyres to the 205 tyres but he said nope but if you change the alloys for bigger then certainly you have to .

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Did someone mention Noisy exhausts? :D

To cut a very long story short :

Plod do sound test using ISO 5130. Static noise test BUT and this is the thing, there is no results limit for that ISO test.

Construction & use regs state 82dB, But again, that test is done by a Drive by test. On an approved tarmac track at 30mph with the use of doplar radar & various microphones set at designated positions on track

SVA cars, (ie. imports) can have an exhaust noise limit of 99dB. but this has to be documented on the original import papers That is a static test as done by ISO5130 and by many race tracks o make sure your track day car doesn't break their noise limits.

MOT testers use discretion. If the tester likes loud cars then you are fine, If he doesn't then he can refuse to test the vehicle.

The problem I had with Norfolk Plod is that they tested at the wrong engine speed. They said 3/4 throttle from Red line, NOT the 3750rpm as quoted in ISO5130

As has been said in posts above. If your exhaust has been modified to make a louder sound than an original system then it would be deemed illegal. (New cars have the dB limit on their V5 document)

if sports Car manufacturers went by the letter of the Plod made up law, none would be legally allowed on the road.

In a recent static test we did at work we had a Ferrari at 109db (standard factory exhaust) Exige at 99dB, Aston at 101dB, Porsche at 96dB. All sounding absolutely beautiful.

Made my 94.1dB sound like a mouse.

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Got a reading of 112 on mine at JAE but the meter was a bit sus. Splinter won at 119 :lol:

Mind you, you can't do "Lift" static so lord knows what it is then!!!

The law is a ass!

Edited by daytona
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How comes you can't modify to a 'louder than original exhaust' but some cars come standard with one...

That doesn't make sense. If a car has a standard exhaust then it is a standard exhaust.

An OEM exhaust system must be passed by legislation. If a vehicle does not pass any of the many and various legislative tests that are placed on the motor industry then the vehicle is not permitted to be sold.

Smaller manufacturers have a greater leeway with legislation than larger manufacturers. Small being less than 1000 units sold per year.

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its not loud until you need earplugs and you turn a multistory carpark into a car alarm disco

security once refused me entry into a carpark in glasgow because they remembered my car from the week before :sofa:

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its not loud until you need earplugs and you turn a multistory carpark into a car alarm disco

security once refused me entry into a carpark in glasgow because they remembered my car from the week before :sofa:

i would say thats what my brothers saxo sounds like unless im getting too old for real loud exhausts hehe

i wouldnt say mine wakes the dead as its fairly quiet on idle but when you rev it it sounds nice and a bit more lively

Edited by celica1977
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nope it was louder than that :P

onto the original point though. im pretty sure that any non standard exhuast technically isn't legal regardless of sound

yep thats why i opted for midrange rather than loud and when i spoke to the guys who put mine together , we get a lot of younger kids who want a loud system with straighthrough pipes and we cant guarantee that the car would pass a MOT or go with the plod .....yet they still went through with their decisions lol.

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