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  1. #1
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    IVA Noise measurement: dBA or dBC ?

    Can anyone tell me whether the noise measurement is made on the dBA or dBC scale?
    The IVA manual does not specify.

    I think it should be dBA, but whilst playing with the meter I noticed that dBC ups the recorded noise level of ambient background noise quite a bit.
    Crendon Chassis No.49
    Huddart FE428 + toploader

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  2. #2
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    dBA. Is what they should test at.
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  3. #3
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    Thanks Dave.
    Crendon Chassis No.49
    Huddart FE428 + toploader

    Not listed in the Shelby Register.

  4. #4
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    Has to be below <100 dBA @ 4750 RPM.

    Alan.
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  5. #5
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    Quote Originally Posted by AKCobra View Post
    Has to be below <100 dBA @ 4750 RPM.
    Only if Kev's engine makes maximum power at 6300rpm, surely? The manual says "run the engine at 3⁄4of its ‘maximum power’ speed", although does follow it up with "Where the engine maximum power speed is not available, thetest may be carried out at 2/3 of engine maximum design speed" - so if he doesn't know maximum power speed then I guess it's 3/4 of the redline.. even then, on a 428, I'd assume max RPM is going to be ~5-5,500rpm - Kev?
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  6. #6
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    yup, my prescribed engine speed is below 4000 rpm.
    The limit is indeed less than 100dBA, but it is actually 99dBA max, so 99.5dBA is a fail.
    Crendon Chassis No.49
    Huddart FE428 + toploader

    Not listed in the Shelby Register.

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