Black flagged on track day due to noise. 102dB help!

[Simbo]

Hi.

Track day yesterday at Donington in my S/C Atom 3.
The noise police had me at 102dB early on and I thought it was a one off as I've been a few times this year with no problems unless I hit the rev limiter. Mine does pop/bang occasionally on limiter or gear change.
(I fitted shift lights so I change earlier and it's been ok since).
Next time out 102dB again and it's home time.
There was another S/C Atom there and we had a chat and compared sounds stationary revving with an i-phone app, also our ears and they sounded pretty similar.

Anyone had a similar problem?
Anyone know exactly where on track to keep sound to a minimum?

Thanks.

[Monza]

Do you have the catalyst ?

[Simbo]

Hi.

No catalyst.
The other Atom there didn't either though.

[Monza]

Catalyst helps to reduce noise but this doesn t explainer why your Atom makes more noise tjan the other one. The only thing i know is that the way to press tje throttle for this test is very important, be very smooth with a low revs increase with no fluctuation if possible.

[Peter255]

[quote="Monza"]
Catalyst helps to reduce noise but this doesn t explainer why your Atom makes more noise tjan the other one. The only thing i know is that the way to press tje throttle for this test is very important, be very smooth with a low revs increase with no fluctuation if possible.
[/quote]

Whilst I agree with what you say, that is not much use on track! The black flag will be because he tripped one of the circuit drive-by noise tests. There is not much you can do unless you either know where they are, or fancy short shifting all day long.  They are also notoriously un-fair as wind direction and other cars affect the readings.

I think the best approach is to find out where the drive by meter is stationed and don't convoy past it (as the noise all adds up!) and cruise past a mid-throttle with no gear changes. Not ideal, but do-able if there is only one meter and you know where it is! 

[911tom]

I'm yet to get the atom on track but have had this in another car. The marshals pointed out where the noise meters were which was useful but it meant holding back the revs at those points which did take the fun out of the day a little. Some tracks and days have a 105db limit I think. Could be the answer.... or refit the cat for the next track day. How much over were you?

[PeR4]

Usually the exhaust is the main noise source, but sometimes air intakes makes more db, and (from viewing videos) I find the "rubber belt" sound from Atoms w compressors pretty dominant. Is it for certain that the exhaust is the major contributor?

[Monza]

I was thinking it was the static noise test not when driving on track. Catalyst will help in both case becaus it reduce the exhaust noise.

[Simbo]

Hi.

I was 102dB both times I was black flagged and the limit was 98dB.
I think I must have been revving hard or changing gear right under the microphone/detector.
Finding out where they are and making less noise near them seems the best way forward.

[Monza]

Touching the rev limiter is very noisy to.

[levo 1]

I carry my cat in the trailer just incase its a shame to get booted out 20 mins and you are good to go back on track.