db levels - where to take them??

[Meek_racing]

Tried our works db (decibel) reader today and it gave the 96db on my custom exhaust... Where do I hold the thing and at what revs to see if its ok for track?

I want to have a straight through centre section but it seems a bit too loud before I even do that

 

[DanFreemanPhoto]

At bedford, they tell you to hold at 4.5k revs, and they stick a sensor in the exhaust.

 

[fil_b]

also a 20m drive by at full revs i think

 

[Bazzon]

also a 20m drive by at full revs i think

Never had that.

Depends on the circuit, usually they say about 3/4 revs, they normally hold the reader about 1 meter from the exhaust.

If its a drive by there will be a reader somewhere on the circuit.

 

[Ben^]

The standard for testing db should be at 3/4 revs 1 meter from the exit of the exhaust with the db meter at a 45 degree angle.

If they are doing anything different then its there own rules...

 

[J 5 LEE]

http://www.youtube.com/watch?v=PajXVTosO94&feature=related

Hope this helps

 

[Daniel]

At our local circuit, the rules are:

4000 rpm, db metre is held 1 metre away from the exhaust.

 

[fil_b]

http://www.motorsportvision.co.uk/trackdays/trackdaytermsba_c.asp

The regulations relating to noise levels are required as a result of environmental and/or planning reasons relevant to MSV venues and so there is no room for discretionary relaxation. They are reasonable restrictions which ensure activities at the MSV venues create the minimum amount of disturbance to our neighbours. Although these restrictions can seem prohibitive, we operate our retail driving activities, using single seater racing cars and sportscars, in full compliance with these limits. These measures are required to ensure that the majority of track day customers who do not attempt to flaunt the noise limits are able to continue to enjoy their track days without the relevant event or future events having to be restricted due to the acts of others.

All vehicles participating in track days at Bedford Autodrome must conform to MSV’s static noise test limit of 101dB(A). Noise checks to establish adherence to this limit will be conducted in accordance with current measuring methods as defined by the MSA. Essentially this means that the test will be carried out with the meter 0.5m from the car exhaust at a 45 degree angle with the car at ¾ maximum revs.

In addition to the static test mentioned above, vehicles must also comply with our drive-by noise limits. The noise emissions from any vehicle must not exceed 87.5dB(A) measured 20m from the car, which shall be accelerating maximally at over 60mph. Drive-by levels are monitored using noise meters located at several locations around the Bedford Autodrome complex.

If the results of the monitoring show that a particular vehicle is exceeding the drive-by limit of 87.5dB(A), then MSV staff will inform the participant and their vehicle will not be permitted to take further part in the event.

from bedford autodrome