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Sound deadening? worth a try?
number-1 - 13/3/13 at 04:38 AM

Has anyone tried to deaden the sound under the bonnet with sound deadening? Were the results any good? What did you use? My mid engine BEC has a large rear tub and acts like a boom box. I thought about trying something to reduce noise for Bedford in May


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Ivan - 13/3/13 at 07:08 AM

It should work fairly well but has some down sides - namely it's heavy and the best quality is expensive and in an engine compartment you will have to do careful selection to ensure the heat doesn't downgrade the adhesives.

ashg - 13/3/13 at 08:15 AM

i have used this stuff with very good results. you just paint it onto the panel

http://www.caraudiodirect.co.uk/chp-paste-13040-chp-xtreme-anti-noise-paste-6kg-six-pack.html

from experience you don't need to cover whole panels, you just need to damp a section of a panel which is usually enough to stop it resonating.

PSpirine - 13/3/13 at 11:33 AM

To avoid booming due to resonance, try what many OEM's do, and add a mass damper to the panel.

This doesn't need to be "sound deadening" material. A block/piece of steel or other material will do the trick. Sound deadening just happens to be flexible, and thin which makes application easier.

pewe - 13/3/13 at 12:04 PM

As above ^^ you need a mass damper.
On various applications I've successfully used small sheets of lead.
You can either rivet them in place or use something like No-nails, though that might not take the heat - but you get my drift?
A true locost solution??
HTH
Cheers, Pewe10

mark chandler - 13/3/13 at 04:55 PM

Bedford are very prickly on noise, may not be the best choice.

My car squeezed in last year and we had a very good day, when you book let me know as I need to start playing again and would like to see your machine.

number-1 - 13/3/13 at 05:15 PM

Thanks for the replies chaps

The track day is booked for 20th May. A few lads from work are going...Noble, Tiger Cat, Tiger Avon race car, Evo x 2, TVR, M3.

Hopefully i dont get binned on noise. Ive got a GSXR 1100WP engine with a 2004 Kawasaki ZX10r end can. Ive got a standard 1100 WP airbox to mod and go on

MikeRJ - 13/3/13 at 06:03 PM

quote:
Originally posted by PSpirine
To avoid booming due to resonance, try what many OEM's do, and add a mass damper to the panel.

This doesn't need to be "sound deadening" material. A block/piece of steel or other material will do the trick. Sound deadening just happens to be flexible, and thin which makes application easier.


Sound deadening and what is refereed to as a 'mass damper' above do different things. Sound deadening either absorbs sound energy directly (the thick wooly stuff) or absorbs the energy directly from a panel (bitumastic type deadening). These are "broadband" solutions that absorb energy over a fairly wide range of frequencies.

Adding mass to a component is done to move the resonant frequency of that component outside the range of the exciting energy source (i.e. the engine). It doesn't actually absorb any energy, directly or indirectly and is used to fix resonance problems on specific components (which may be body panels). This is great if the OP has problems with specific panels buzzing at a certain RPM, but no good to reduce total sound levels.

Simply adding weight is also not technically a mass damper, since there is no damping component. A true mass damper does absorb energy e.g. the harmonic balancer on the crank pulley is a tuned mass damper, as are the huge weights and hydraulic dampers they put in the top of sky scrapers to stop them falling over in an earthquake or high winds.