Talk Morgan Forums Talk Morgan Members Section Special Information Why Exhausts are Ever Quieter

Our 2017 AMG C43 has a selector to allow the different exhaust modes to be selected.
Our 2019 AMG A35 does not, but by pulling one of the gear change paddles the engine starts in sports plus noise mode.
The new Plus Fours are quiet,
This is why:

https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32014R0540&from=EN

Yes, Europe is legislating the Sounds of Silence.

Tarka has a declared noise level of 86db at 4725 rpm.
The C43 is 95 db at 3750 rpm
The A35 is 81 at 3750 rpm

Given that db is a log scale Tarka and the A35 are really too quiet and need a sports exhaust!!

The C43 in Sports+ mode measured 108db at 4500 rpm using a db meter that clips on an iPhone. . IT is LOUD.. possibly anti social! I love it!

Peter, hoping edicts are not enforceable retrospectively..?

My old 85/6 +8 does not have the benefit of the more usual four silencer set-up, having been cut down to the two under the running boards, and none of that cat kit, it has to date fortunately caused no issues even while touring Southern European countries....
The old thing can purr like a pussy cat on light throttle or roar a bit if and when awakened.... I suspect that the lack of back pressure may cause a drop off in max performance, the latter I personally have experience of, and I too tend to make a lot of noise of rudely awakened while purring away in my armchair..

I guess in time it may be expected that in areas where one might be tempted to put the boot in, that noise detectors will be linked to the cameras etc.etc.etc.. Sigh..!

You need side exhausts on Tarka

Traffic noise harms health in numerous ways. Protracted noise-related stress can exhaust human physical reserves, disrupt the regulatory capacity of organ functions and hence limit their effectiveness. Traffic noise is a potential risk factor for the development of medical conditions and incidents such as high blood pressure and heart attacks. The effects of traffic noise should be further researched in the same manner as provided for in Directive 2002/49/EC of the European Parliament and of the Council ( 3 ).

Guess it explains why I often need a nap at lunchtime, take pills to control my blood pressure, oh and am slowly loosing my hearing, although that's probably a benefit

North Yorks police are rumoured to have bought some of those to test!!!
Cheers
John

No, nothing retrospective: your car should meet the noise level shown on the V5. Tarka does, at Castle Combe it measured at exactly 86db, as on the V5.
It has only single, under running board silencers, nothing between there and the end of the tail pipe. Even so it just murmurs whilst being driven sensibly, but the noise level is as much dependent on amount of right foot applied as revs delivered. A full stab to the metal and the exhaust and inlet noise are way above the stated level!


I suspect the N Yorks Police are more interested in noisy bikes than cars. If they measure a noisy car what can they do, if it appears to have a normal exhaust system? They could demand a MOT re-test, but the sound level isn't part of the MOT. Their meters are not evidential devices. So all they can do is use the noise as a means to conduct a full vehicle safety check. On a Morgan they wouldn't have any idea what is "normal", and I suspect nor would their VOSA Henchmen! Indeed Morgan Motor Company doesn't know what was "normal" when a car was built!

Side pipes for Tarka perhaps ?

Given the beautiful peace around during lockdown, I'd quite like the world to continue being a quiet place when it's all over. It's like speeding, isn't it..? Everyone does it but everyone hates it when you're out walking..

I have the "43" engine in my Merc 4x4 and in Sport + last time I drove up Cheddar Gorge I swear I saw the rocks crumble. The +8 is on side pipes, there was no stuffing left in the boxes. I have a John Eales engine from the 90s. In Switzerland 5 years ago in the tunnels the guy behind me said it was flaming out of the pipes. And I did get banned from a track day a few years ago. 106db but as I promised to drive past the noise meter slowly I was allowed to continue. My hearing isn't what it was so I did have the boxes cut open and some "sound insulation" added and welded close. I do (or did) 6k miles a year in the car and had some ear plugs made by a company in London. They specialise in ones for musicians. They scan your ear canal and 3D print them. Fit perfectly and they weren't expensive.

I notice that the sportscars that used to start with a flourish in loud mode now start in quiet mode and you need to select the loud/sport mode.

I think Aston or Jaguar made a point of calling it good neighbour mode.

The AMG ML63 I have starts in open exhaust mode and makes quite a bark. Then when it's done 30 secs it drops to quiet mode. I try and avoid parking with the exhausts facing the neighbours if I have an early start. Still love it.

Having said that it's nothing compared to the Coupe with the dual sidepipes.

Too louder exhaust note drowns the possibly more agreeable induction note heard and enjoyed by the driver rather more than pedestrians. I'm thinking of my Roadster (with extra 4 inch hole in airbox) as it passes through 3500 rpm. Poor mans V8

I don't know about the UK but in most countries it is illegal to modify exhaust system, remove cats, etc. Naturally I would never do such a thing

The law is buried in here somewhere:

https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32014R0540&from=EN

If you have an allergy to Horlicks, it's the perfect document.

For the UK the MoT will test the car against rated factory settings.

You have three years prior to this, however this is usually during the warranty so anything done to the car will probably invalidate this!

I do know slightly mad people who de-cat and adjust the exhaust on almost new cars but then more money than sense springs to mind given the way I have seen them drive.

Richard, I too enjoy the sound of induction never more so than when messing around balancing the twin Webers on my Elans many years ago, though for a real sense of induction roar while in the drivers seat, it must be hard to beat a mini with the Weber protruding into the passenger compartment through the hole in the bulkhead where the speedometer used to live.... Backfires, and wearing loose items of clothing were best avoided for sure...

Running an older car sans electronic and emission gubbins can have its advantages, but even my car did not escape completely as it is fitted with an auto choke mechanism where I would much prefer a simple choke cable. but then best not to get too cocky for older cars like mine may be amongst the first to suffer some sort of legislative decree if Climate change really takes hold in time. and even at this time cars without cats are seemingly banned from some cities outside the UK..? NOT that I tended to frequent large cities by choice while touring... I suspect I may be one of the very few who just drove past Rome while touring Italy in my old Morgan..!!!

Not Quite....

From May 2018
Noise suppression system

The Tester will inspect:

exhaust silencers
under-bonnet noise deadening material fitted as original equipment.
Exhaust noise will be assessed during the emissions test for the vehicle or by revving 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 normally expected from a similar vehicle with a standard silencer in average condition.

No mention of using a sound pressure meter.

Also, to become a MOT Tester you do not need a hearing test.

Peter, thanks for providing the extra detail. good to see that there seems to still exist some grey areas in legislation...(-:

As far as my memory allows my +8 sits at circa 2500rpm in 5th at 70mph purring along reasonably quietly, other than wind noise..(-: In reality noise production on my old Mog depends upon not just the revs but the amount of throttle pedal pressure applied to get there..(-:

You will find that going forward, it will all become much more quieter. Most OEMs haven't yet implemented the full new mandate for various reasons.
1. The current vehicles they are building will be replaced by the cut off so no sense in spending on R&D, especially in this climate
2. The sound of a sports car is a selling feature so they will put it off as long as they can
3. We have another round of EU mandated emission standards to go through, much like WLTP, at which point I can see some OEMs rolling revised exhausts to do it in one go

https://www.vehicle-certification-agency.gov.uk/fcb/cars-and-noise.asp

The dreaded WLTP testing cycle has also dealt a blow in regards to engine/exhaust notes. Many OEMs have had to add gas particulate filters to their engines to meet requirements which has muffled what used to be many great sounding sports cars. I met up with a friend who has a 2016 version of my 2020 Porsche and his sounds oh-so-much-better!

In short, if engine induction and exhaust noise are your thing, it's best to get something in the next few years while you can

What's really quite funny is that you can get active exhaust noise generators to give your silent EV that V8 rumble etc.

https://youtu.be/HmDXE3o8dMc?t=335

How will they legislate against those?

My brother is a MOT tester. He MOTs a youngsters car with go faster stripes that sounds ok. The day before it sounded like an earthquake, the day after sounds like an earthquake again!!!