Quieting an "Ulster" Exhaust

[John P]

Hi,

Now that I finally have my Ulsteroid running I'd really like to do something to make it sound better.

The car was built on virtually a zero budget some years ago and has always been quite rattley.   Some of the noise certainly comes from the engine and may well be due in part to the flattened cam followers but the majority of the noise seems to be from the exhaust.   The engine was re-bored and the crank re-ground when I built it so I don't think there's an issue with wear.

The car has an Ulster style manifold which was an Autojumble buy and not brilliantly made although it looks the part.   This is bolted to a Brooklands style silencer made by a friend who, at the time, was making them for Alan Raeburn.   

Unfortunately he's no longer here to ask but I suspect that inside the case are just two tubes running parallel to each other.   I can't check as the pipes curve into and out of the box so you don't learn much by looking down the end.

The exhaust then runs in the normal manner to a fish tail at the rear.

I'm very reluctant to start cutting holes in the silencer just to have a look and wondered if anyone had any other clever suggestions I could try to at least determine what I could do.   I believe some motorbikes use decibel killers but have no idea how they work or even if they would be available in such a small diameter.

Any advice,
John.

[Peter Naulls]

John,

Before disassembling the silencer it would be worth taking the fishtail off first to see how much noise that is generating. I removed mine for a while to avoid upsetting the neighbours; it made a big difference. I have since found that welding a link across between the two sides cuts down of the rattley resonance a bit.

Peter.

[Howard Wright]

Hi John

Motorbike “quieteners” are all quite large diameter. Certainly more than the 1” diameter pipe I guess you have.

I think your best option is to bite the bullet and open up the silencer and wrap some deadening felt around the pipes.  The pipes should also be perforated.  I’ve just added a length of perforated pipe wrapped in silencer felt to my special (however my exhaust is 60mm diameter).  Makes a huge difference.

If you can, make it easy to disassemble the exhaust easily as the silencer felt tends to burn away after a while (according to my biker friend).

Cheers

Howard

[Ian Williams]

The Ulster silencer design is nothing like you imagine Howard simply an expansion box so your suggestion is not one I would make. An Ulster sounds distinctive because of the exhaust design, its part of the character of the car.

[Henry Harris]

Hi,

Now that I finally have my Ulsteroid running I'd really like to do something to make it sound better.

The car was built on virtually a zero budget some years ago and has always been quite rattley.   Some of the noise certainly comes from the engine and may well be due in part to the flattened cam followers but the majority of the noise seems to be from the exhaust.   The engine was re-bored and the crank re-ground when I built it so I don't think there's an issue with wear.

The car has an Ulster style manifold which was an Autojumble buy and not brilliantly made although it looks the part.   This is bolted to a Brooklands style silencer made by a friend who, at the time, was making them for Alan Raeburn.   

Unfortunately he's no longer here to ask but I suspect that inside the case are just two tubes running parallel to each other.   I can't check as the pipes curve into and out of the box so you don't learn much by looking down the end.

The exhaust then runs in the normal manner to a fish tail at the rear.

I'm very reluctant to start cutting holes in the silencer just to have a look and wondered if anyone had any other clever suggestions I could try to at least determine what I could do.   I believe some motorbikes use decibel killers but have no idea how they work or even if they would be available in such a small diameter.

Any advice,
John.

There's nothing inside! That's how it's supposed to be.
http://www.austin7club.org/How%20To%2011.htm

[Bob Culver]

I presume the definiton of exhaust port does not include the small net area immediately below the valve head.
The silencer may not be constructed in accord with the rules.
Is sound outside the car the problem? The rigid mounting throughout transmits a lot of noise into the bodywork. non purists may substitute various flexible mounts.
If really curious, many servicemen now have inexpensive  endoscope type gadgets
Altering silencrs can significantly alter mixture.

[Charles Levien]

Keep it “straight thru” and wear ear plugs on a long trip.

[Mike Costigan]

... or sell the Ulster and buy a Nippy 

[David Stepney]

I remember a time when the louder the exhaust, the bigger the grin!

[John P]

Actually it's not how loud it is but it just sounds really rattley.   I'd hoped to be able to achieve a more "rorty" sound and have heard other cars at VSCC events which do have a much deeper and more consistent sound.

If you hold the body of the Brooklands style silencer it does seem to dampen out some of the unpleasant noise so I guess it's probably resonance being amplified by the flat sides of the silencer.   

I did consider drilling a hole right through the silencer and then passing a bolt right through so that the two faces were under pressure but I'm a little reluctant to damage it in that way.   Perhaps I can somehow clamp the faces for a trial just to see what happens.

May also try removing the fish tail to see what effect that has.   Mine doesn't have the small holes drilled into the outer face of the fish tail so this may be something I can try if removing it has any effect.

John