Talk Morgan Forums Morgan Sports Cars Morgan Aero 8, 2012< Plus 8, SuperSports, Coupe & Aeromax Side pipe exhaust

Does anyone know the internal design of our Aero8 side pipe silencer?

I ask because I could get the exhaust maker to copy the internal but modify it slightly to give better bass and still give us the distinctive flatulent sound of the Aero....if you see what i mean

Sounds like one for Cerealsurfer Kin.

I have an old Aero silencer laying around in my garage which I can take a look at if you would like... I ran my Aero with no exhaust and no cat's once to get a listen to the engine straight out of the silencer...

IT:S BLODDY LOUD..........

The Sports pipes available are a larger diameter and have less venting in the central tube within the silencer box itself. If you have the same silencer below the runningboards as the regular rear exit type cars. (obviously with a 90degree bend to exit the bodywork)

You could just purchase the Librands front silencer... but you would need to get a larger diameter 90 degree bend as the central pipe is larger than stock. (could cause fauling problems with the recess cut into the runningbaord though)

Alternatively you could just sleve the stock silencer... probably more barky though.. I ran my TVR Cerbera 4.5 with no silencers or cats.... 130db... almost break large panes of glass and sets off car alarms.. it was nice to see the flames though.

Thanks, but I doubt the internal design is the same as the side pipe exhaust.

Less venting? do you mean less perforation in the central tube? If so, what effect does it have on sound wise?

I could get the exhaust custom made for around £300 each

What do you mean by sleeve the silencer?

Not so sure on that... however.. I'll take a look at a side piped car at our next meet.

Indeed.. less perforation. This allows more of the exhaust pulse to exit the exhaust intact (ie not diffused). However without matching the diameter you end up with more of a bark than a deep woofle.

Fair enough... I would expect that even with the Librands front silencer you would need a custom 90 Degree bend anyhow.. If you can get them custom made then it's a one stop shop. A custom exhaust manufacturer will be able to achieve what you need by describing the effect you want. ie. deeper base etc.

Insert a pipe of the correct size down the tube in the silencer then weld into place.... thus removing the silencing efect all togeather... or insert a % of the way to achieve desired sound....Cheap as chips and easy to modulate. Requires no fabrication. This will generally make the exhaust a lot louder as well.... more like a cherry bomb effect.

The side pipe has a very distinctive flatulent sound(almost sounded like a Harley Davidson) whereas the rear sport pipe would sound like a...err...V8rumbling/TVR like
Therefore I believe the internal design would be different to that of the conventional rear...
Heres some pics I've took of my side pipe:

This pic shows the inlet into the silencer..Pipe diameter approx 2 1/4"


This one shows the outlet, note the 90degree bend is approx only 1" in dia. and I don't think its straight thru design




Looks like the cheapest way is to sleeved the inlet with non venting tube

Would you be able to design a side pipe which would give me that extra v8 rumble when idling...draw it on a paper and post it?

thanks for the explanation, otherwise would have no idea what it does to the sound

The main problem you will have is that the Morgan V8 exhausts (1 for each bank) are not linked... which gives the American V8 rumble as found on TVR's (except the Cerbera... these are seperate as well). Funnily enough this also robs the engine of some potential power as exhaust pulses can be used to provide additional suction (scavenging effect) for the next firing cylinder on the other bank.

Anyhow.. the silencer is the stock unit from the standard Aero with a different back-plate and 90Degree pipe added. 2 1/4 inch inlet pipe is about right but as the primary pipes are SOOOOO small this is unlikeley to be the main problem with an exhaust.



The reason this pipe is only 1inch diameter is that it needs to get round a very tight bend... pipes can only be bent to a certain radius and that requires distance... larger pipe more distance it takes to create a 90degree bend... 1inch is obviously the maximum size that can be used to get round the bend in this distance.

Obviously this is not really ideal as you'll have 2 1/4 inch pipe at the front going in and 2 1/4 within the silencer and then a restrictive 1inch exiting !!!

The gasses will have to be accelerated to over 2 x inlet flow to exit which will cause a backpressure to the engine... because it has to "pump" the gasses out of the silencer

I've been looking at some of the racing Aero's and I'm sure i've seen either Keith Alhers or the Latest GT racer have a side slashed exhaust... meaning that probably a 2 3/4" pipe exiting the running board with no bend but attached at an angle to the silencer (if it has one - probably not). This would be a better performance option, and give a deaper note... but would enevitably require mods to the runningboards...

funily enough the flatulent sound is likeley to be down to the 1" pipe 90 Degree bend... which I'm afraid to say that given the restrictions of the other brackets under the runningboards would be dificult to work around.. without shortening the silencer and providing a longer distance to make a compound bend (bending outwards in 2 stages)

I'll try to pencil some sketches out.



having looked at the pipework exiting the bodywork... I think adding a sleve will only generate a real BARK... just like GT racecars and it will be pretty earsplitting.... No deep woofle I'm afraid.. if you are after a deep woofle then the silencer would need to be changed and as I said above some more fancy pipe bending to get the exit angle with a larger diameter.

Under race (max Hp) conditions the diameter of the final sections (ie not header) should be 2 1/2 - 2 3/4 inches...

more towards the larger size.. because this tends to increase HP when tested as the Aero's have Cat's. This really comes down to experimentation within the implementation.


No worries.... for more info.. take a look at Four-Stroke Performance Tuning by A. Graham Bell... Ed 3 now out. ISBN 1 84425 314 7

Thanks, I think I understand most of it, but there're still a few questions I wanted to ask, if I gone for straight thru design, would the engine be running to lean? I guess the sound would be awesome, but probably unbearable over long distances

I'll be using this company http://www.jpexhausts.co.uk/
Heres a pic of my dodgy sketch...



Fig "A" is the std sidepipe, but no idea what the internal design looks like.

Fig "B" is a cut away of my proposed internal design, I'm hoping this might give me the bass/woofle I needed without being too loud, the material will be made out of mild steel rather than stainless as I believe stainless gives out more hard edge sound.

Your comment of this design will be much appreciated even if its a bad one

Nope... by this point most of the engine characteristics are dictated by the first 3-4 feet of the exhauset, header length (which should be a LOT longer than Mog Stock), collector shape/style (4-2-1 or 4-1 with some sort of gass accelerator flange) & cat structure. The only sensors are before and after the cats so final tail section will not alter it much... the push from the engine will far outweigh the limitations downstream.

It depends.. if you "straight through" the exhaust then the sound becomes very harsh and imposing... even at rear exit exhaust on an Aero with race cans is 104db.



The internals could be one of 2 designs either an "S" where the pipe loops the internal in a S shape starting from the input to the output, Secondly 3 lateral pipes which are linked at the end to a common core thus offering pulse interference, both using pipe that looks similar to the following:



Imagine the following pic but with a third pipe allowing a full "s" (sorry the pic did not come out - look at the first of the links at the bottom for a diagram)to be made or just a 3rd pipe in the centre that is internal only. As the Morgan pipes have the input and the output pipes on opposite sides. They are VERY Heavy as well.

To be honest without cutting one open it's difficult tell.. anyhow below are some pics which are usefull and also try google'ing "muffler internal" and you'll get an idea of the combinations.





You need to look at the following links and get your head round the design aspects such as Helmholtz Resonators
Internal Muffler Design Aspects
Helmholtz Resonators

Alternatively .. once your totally confused and had enough... go to JP Exhausts and describe what you are trying to achieve. No doubt their engineers will have a particular approach and prefered design... and will inevitably produce something that will work.

At least the info above will enable you to understand what they are talking about. lol

you should have shown me the links earlier before I made a fool out of myself

Now, does anyone has a cutaway silencer for the Ferrari