Australian Design Rules - External Noise

[RedRaven]

After hearing a couple of rumours around the traps about the Atom possibly not passing ADR 83/00 External Noise, I decided to look it up. (I think Cthulu did too in the other thread.)

The pdf format ADR 83/00 document can be found here:
http://www.ntc.gov.au/filemedia/general ... DR8300.pdf

Its exhaustive.  The Atom 245 most likely to be imported seems to come in at around 80 or 81 dB, with a 1dB allowance for accuracy.  Its a light passenger vehicle, with a mass less than 2 metric tonnes, and will be rated at about 183kW engine power.  However, there are several tests, a stationary test and a moving test where the vehicle passes the microphone at 7.5 metres.

At full throttle passing at about 61km/hr (38mph)  

The ADR can be considered equivalent to:
United Nations Economic Commission for Europe Regulation No. 51 Uniform Provisions Concerning the Approval of Motor Vehicles Having at Least Four Wheels with Regard to Their Noise Emissions, incorporating the 02 series of Amendments, up to and including corrigendum 1 to supplement 3 to the 02 series.

I have no idea if the Atom meets this UN specification.

Without having the actual vehicle specs to hand, I can't further elaborate, but if the Atom 245 satisfies a driveby at full throttle at 7.5m distance with a passing speed of about 61km/hr...reading 82dB on the noise meter then it should pass the ADR.

I also found two errors in the document, which wasn't very encouraging.
If anyone else knows how to read ADR legalese - please correct me as necessary! 

[Monza]

The Australian norm is same as EC norm for noise.
I had tested officaly a standard Atom 245 : results was 93 dBa ...
After some modifications, i had made a new test with a result of 86dBA.
I'll make new tests with other modifications on my new Atom 300 and try to go near 78 .
Intake noise and exhaust noise are both a problem and the "open" engine configuration of the Atom is a supplementary one !
I'll test the Atom with a Civic Type R exhaust/silencer and air intake so that i'll know what is the part of noise from "open" engine configuration.
This is a real hard test with an Atom ...
Last solution : put a valve on the exhaust line to use a special exhaust line for the test, as many cars are doing (from Ferrari, Lambo, Cat CSR ...).

[RedRaven]

Is the Atom louder than a Subaru WRX at full song? Was sitting next to one at the lights when it took off sharpish and that was fairly loud.

Interested to know what sort of mods you can do to make the Atom quieter for testing etc.