From: Soren Barr (sorenbarr@worldnet.att.net)
Date: Sun Jan 25 2004 - 12:35:13 PST
In general noise regulations in the U.S only look at overall sound level, on
an A weighted scale (A weighting is as the human ear hears it) and 86 dB is
pretty loud.
Exhaust is normally the biggest component of overall noise on Diesels, so
your best bet is to find a good muffler for the vehicle. This might take
some trying, but a good truck shop should have a line of mufflers to choose
from. I'm partial to Donaldson mufflers, since I'm an exhaust engineer for
them.
You may also need to look at other sources of noise to cut overall levels.
Tire noise can be significant on a military vehicle, but only if NJ measures
the vehicle while moving. General mechanical (including turbo) noise can be
a problem too, but there isn't much you can do with that. Focus on the
specific items that are causing the most noise.
Make sure you find out how the state measures the sound, at what RPM or
range, moving or not, etc. and focus on quieting it down that way. A local
truck repair shop may have a sound level meter, since this is an issue for
semi's too. They may also know the state regulations and how to work with
(or around) them.
I hope that helped.
Soren Barr
-----Original Message-----
From: Robert Soar <billy_ruffian@fireflyuk.net>
To: Military Vehicles Mailing List <mil-veh@mil-veh.org>
Date: Sunday, January 25, 2004 10:24 AM
Subject: Re: [MV] Noise level of a diesel k60 engine
>On Sun, 25 Jan 2004 09:39:19 -0500, My email <jonwatters@cox.net> wrote:
>
>> Hi, I have a question on the noise level of a certain k60 diesel engine
>> made by rolls royce
>> used by britih military APC like the FV432. I was just looking over the
>> possibilities of making one street legal.
>
>I'll ask my two FV-432 owning friends when I next see them though it's not
>a problem we have here in the UK. Generally sound deadening in a vehicle
>involves quietening the exhaust, preventing panels vibratingand,
>presumably stopping sound being reflected around and out of an engine
>compartment
>>
>> Rhode Island law states that a motor vehicle cannot exceed 86 decibels
>> at 50
>> feet. And I was just curious on your opinions on if you think I can
>> obtain
>> this with a 15 ton APC like the fv 432 mk2. Can you modify an engine to
>> run
>> quieter?
>
>The engine may not be the problem. Depends what frerquencies your
>legislators measure. One of the reasons that two strke engine vehicles are
>less welcome on out local green lanes is that the frequency of the engine
>is more noticeable at a given volume than the low speed burble of a Land
>Rover. Don't forget you have transmission and track noise to consider too.
>My Ferret is relatively quiet engine wise but the combined noise of
>gearbox, transfer box 6 bevel boxes and 4 epicyclic hubs makes it a fairly
>noisy (and distinctive) beast.
>Regards, Rob
>>
>> Thanks for any help or answers.
>>
>> Jonathan T. Watters
>> Tiverton, Rhode Island
>>
>>
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>
>
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