08-04-2021, 03:33 PM
Hi,
Last year I asked if anyone could suggest how I could improve the sound of my Ulsteroid which has a Brooklands style “silencer”.
Although it is quite loud what I was actually trying to achieve was not so much to reduce the volume but to make it sound less rattly.
Since then I’ve tried a few of the suggestions but have concluded that what’s possibly happening is that the silencer, which is in effect an empty box with flat sides, is resonating as the exhaust pulses expand inside it. The flat sides transmit this noise to the bonnet side which is immediately behind it and this acts as a sounding board amplifying the noise further.
If I run the engine without the bonnet sides in position it certainly sounds a lot better so I’m looking for a low cost method of damping this panel.
I know you can buy sound deadening material but it looks like you have to buy much more than I need which would be quite expensive and it also needs to be non-flammable as it’s very close to the exhaust.
I did consider bonding a 4 inch square piece of aluminum (or even lead because it’s acoustically dead) to the inside of the panel with a structural adhesive to see if this would help but I’m not totally happy with this and removing it would probably be an issue if it didn’t work.
Any further suggestions?
John.
Last year I asked if anyone could suggest how I could improve the sound of my Ulsteroid which has a Brooklands style “silencer”.
Although it is quite loud what I was actually trying to achieve was not so much to reduce the volume but to make it sound less rattly.
Since then I’ve tried a few of the suggestions but have concluded that what’s possibly happening is that the silencer, which is in effect an empty box with flat sides, is resonating as the exhaust pulses expand inside it. The flat sides transmit this noise to the bonnet side which is immediately behind it and this acts as a sounding board amplifying the noise further.
If I run the engine without the bonnet sides in position it certainly sounds a lot better so I’m looking for a low cost method of damping this panel.
I know you can buy sound deadening material but it looks like you have to buy much more than I need which would be quite expensive and it also needs to be non-flammable as it’s very close to the exhaust.
I did consider bonding a 4 inch square piece of aluminum (or even lead because it’s acoustically dead) to the inside of the panel with a structural adhesive to see if this would help but I’m not totally happy with this and removing it would probably be an issue if it didn’t work.
Any further suggestions?
John.