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

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!!!