Atom 4 noise measurement reference thread.

[Peter255]

I am thinking about booking some track days. But this is obviously limited by noise limits. I don't want to waste time and cash with black flags!

Has anyone with a 4 got any figures to share for the car with / without the sports back box and with / without the cat (320/350).

This would be a good list to pull together for reference.

Atom 4 320 stock silencer
Static -
Drive by -

Atom 4 320 sports silencer
Static -
Drive by -

Atom 4 350 stock silencer
Static -
Drive by -

Atom 4 350 sports silencer
Static -
Drive by -

Cheers
Peter

[markwetherall]

mine registered 92db at Oulton Park at 4000rpm. 350 upgrade with stock exhaust.

I had no issues with drive by at either Oulton Park or Anglesey

[Peter255]

Thanks Mark.

Atom 4 320 stock silencer
Static -
Drive by -

Atom 4 320 sports silencer
Static -
Drive by -

Atom 4 350 stock silencer
Static - 92db at Oulton Park at 4000rpm (markwetherall)
Drive by - No issue at Oulton Park or Anglesey (markwetherall)

Atom 4 350 sports silencer
Static -
Drive by -

[PaulF]

From what I've experienced, it seems to be a lot quieter than the 3 with a SC.

[phil4]

My old Ducati used to sound thunderous, but on any track noise meter was well below limits (much to the surprise of track marshalls too).

I concluded that the average noise meter is measuring higher frequency sounds (the ducati was more like thunder). Something old SC atom was very good at generating.

Perhaps that's partly why the new one is quieter.

[CAG3D]

Pete, Old Bill was fine at Bedford last year. I was slapped on the wrist a few times though


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[Peter255]

Pete, Old Bill was fine at Bedford last year. I was slapped on the wrist a few times though


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What was his car setup? 350? And which back box? Stock?

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[wasp]

Pete, Old Bill was fine at Bedford last year. I was slapped on the wrist a few times though


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What was his car setup? 350? And which back box? Stock?

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Bill's car is a 350 with standard exhaust.
Cheers,
Stu

[Peter255]

Thanks Tony & Stu

Atom 4 320 stock silencer
Static -
Drive by -

Atom 4 320 sports silencer
Static -
Drive by -

Atom 4 350 stock silencer
Static - 92db at Oulton Park at 4000rpm (markwetherall)
Drive by - No issue at Oulton Park, Anglesey, or Bedford.

Atom 4 350 sports silencer
Static -
Drive by -

Anyone else got any figures?

[Peter255]

I have also just bought a decibel meter so I will do some testing of my car and any others at the next meets and add it to this thread.

[autobackup]

There are some quite good free decibel apps available from both the Google and Apple app stores

[Anon]

There are some quite good free decibel apps available from both the Google and Apple app stores

Those apps are a waste of time really. The microphone in a smartphone is just not designed to capture the high-frequencies emitted by cars. The only way is to use a proper device if you want any accurate reading to decide whether you will be black flagged or not. At the track they also don't use smartphones.

[autobackup]

Simon

I fully accept your very valid points however I was really only intending to point out that these apps can give an idea of the noise level of your car.

As to the frequency response of smartphone microphones it rather depends on the quality of the phone used - certainly some iPhone models use dynamic mics which have fairly narrow frequency range microphones fitted but anything that gets from 200hz up to circa 20000hz (small diaphragm condenser mics) or higher should be fairly adequate for the job!

[Peter255]

My view is that the cost of a dedicated noise meter is significantly less than even a cheap track day so its well worth having to avoid any worry over black flags.

I think it will be a useful and interesting tool to bring along to meets where I can test peoples cars and post up the results here.

Peter

[CAG3D]

I guess the surroundings have a big impact. With noise bouncing off buildings etc.
Plus the meters are set certain distances on certain points of the track.
I had a black flag at Bedford, with my STANDARD exhaust, so when called in they told me which one was picking me up and suggested a higher gear (yeh right!), or try to take a wider line, which I did, and all was fine.
So it all works on small margins and a number of different factors too.



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