Talk Morgan Forums Morgan Sports Cars Morgan Aero 8, 2012< Plus 8, SuperSports, Coupe & Aeromax Bloomin' Sidepipes

Today the Supersport failed (quite impressively) its Swiss MFK - recording a rather impressive 96dB on the noise control. A full 10dB higher than the number of the Certificate of Conformity.

Apparently such impressiveness is frowned upon by the Swiss powers that be - and the car promptly failed.

Any suggestions on how the car could be encouraged to pass (even temporarily).

would something like this be suitable as a temporary measure whilst in the testing station -

https://www.merlinmotorsport.co.uk/p/bs-approved-silencer-baffle-kit-excnrk

not sure on your set-up,but if the pipes are straight, these might be made to fit....?

James

Brillo pads and chicken wire were the order of the day once upon a time...



Em

I suspect the CofC is based on the rear exhaust...Tarka has 86dB on the document and at Castle Combe at 3500 rpm that is exactly what it produced.

The UK MOT doesn't (yet?) require a noise measurement, only a subjective assessment by the engineer.....and there is no check on the hearing of the tester!!
This is the exact wording....

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.

They are more concerned about the mechanical security of the system. If there are clips pr brackets damaged or missing then it is an automatic fail.

Yes you could do this - it's how they temporarily baffle engines at racing circuits. Temporary measure only as it doesn't do the engine a lot of good in extended use.

86dB on mine too - at 4725rpm.

The importer says that it would passed when it was imported in 2013 (5 years ago) and also said "bring it, we'll see what we can do" - which means "open your wallet over there - empty the contents - and then move along to the organ removal room"

My first thought was to remove the rear mufflers - and see if I could "bodge" a solution for the 15mile round trip to the testing station - but the consequences of a bad bodge aren't worth contemplating.

It is a James May "Cock" moment of the biggest order.

I basically need to unbolt the side exhaust - insert a noise reduction modification - bolt back on without it being visible externally.

I can't believe that the rear muffler part has degraded 10dB in 4.5 years and 12,000km - no matter how many times I have allowed the engine to see its top end!

Not intended for extended use just to pass a noise test,it works.




Em

Would it work for 15miles you reckon?

Last time the M3 failed a noise test (at Bedford) they just told me where the microphones were and suggested I upshifted early - and if I got too close they would let me know!

(The exhaust had delivered a slight rust derived performation!)

Only ever did it for scruitaneering if you just stick the wool up without the mesh it will blow out,have a try before you go for the noise test wrap the wool into a mesh snowball insert up the pipe after the test it can be removed with a small hook. Any resedue wool left up the pipe will either be blown out or rust away in a matter of days.

Em

Given this will happen each year for a short period I would agree with the wire wool/gauze model. If you want something more consistent you can swap out each year then perhaps get an additional set of the sill exhaust boxes and have them more heavily baffled. Swap them out for the examination.

The only other alternative is to flip to rear exhausts for the test or permanently but that leaves a hole in the sill.