Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) 4/4 sports exhaust noise

I've fitted the full Librands exhaust on my 2013 4/4 Sigma. It was very loud and I didn't want issues with the Swiss police. After some trips I decided to fit also the Librands acustic trim. Now its more quiet, but the sound is realy nice.

Thank you for your comments.
Seems that I was right when I expected the Librands to be very loud.

So what's the decision Hannes? Loud or not so loud? I've often thought about a smaller sports muffler but when I am trying to quietly leave the garage on a Sunday morning, without waking the neighbours, I think maybe it is not such a good idea.

You have all got me worried now.
In time I would like to replace the system, and I thought "well, it's Librands for me".
This thread has put me on the doubting side.
I was hoping for a few more BHP by replaing it end-to-end, and a little extra burble sounds good.
I am not so sure any more if it sounds 'loud' - I would like to hear the person next to me on the journey...

GaB: The Librands manifold wih 200cell cat does improve performance and also changes the sound to a little bit more noise.

The Librands muffler... ?? Not decided yet.

I was told that its the manifold and cat that make the difference with regard to bhp.
The rest of the system, although it has some effect, less important.
If the rest of the system is ok, save your self some money…..

Together with a K&N air filter and an ECU fine-tuning the car is much better now.
5th gear makes sense now too. Some 25 more bhp.

Yes, was thinking along those lines as well, but one step at a time...

Cain said at Blenheim that changing the pipe from the manifold to the silencer is a useful change (I have a side exit) and quite a cheap fix as that removes a constriction.

This might end up being thread drift but I've recently learnt that "loud" is a very slippery concept. I have been trying to reduce the decibel level of an aircraft to meet noise requirements. With the original exhaust system it was measured at just over 70db. The measurement involved flying over the mic at a specified height with full power applied in climb configuration, The result was about half a db over the limit for the class of plane. With a very small extra muffler - a German design and it seems very clever and weighs about 250 grams - attached to the exhaust pipe we have reduced the db by about 3db. It doesn't seem like much but the noise levels in the cockpit are considerably reduced and we are now within the law. A decibel is a tenth of a bel and the Bel is a nod to Alexander Graham. So a reduction of 3 db is very significant regarding the loudness that one perceives. Others who know more about this might jump in here.

But what I want to know is - how do motorcycles get away with the enormous noise they produce while a slightly loud Morgan would not pass the test? I suspect it has something to do with where the throttle opening is as one passes the mic. i.e. accelerating or decelerating. And yes I'm a bit bitter about all of the bother and expense of conforming when my planes' noise is way less than the 125 cc Vespa down the street. Like most Morgan 4/4s. Even those with Librands side exhaust.