CHCH press had the following.
Wellington: Measures to silence noisy vehicles are almost ready and will take effect in the next few months, Transport Safety Minister Harry Duynhoven says.
"Transport officials are investigating the implimentation of a robust and repeatable objective noise test to suppliment the subjecive noise test currently used by warrant and certificate of fitness testing agents" the minister said in a statement yesterday.
The objective noise test would be based on the international ISO5130 measurement of exhaust sound level emitted by stationary road vehicles and the Australian National Stationary Exhaust Noise Test Procedure.
Both methods measure exhaust noise using sound equipment placed half a metre from the tail pipe.
The minister said he was finalising interim measures, including ordering testing equipment and finalising test site locations
This PDF has a good lot of info on the proposed noise regulations
http://www.transport.govt.nz/downloads/vehicle-noise-review.pdf
One thing that I am rather pleased about is that they don't appear to mention testing while revving the sh|t out of the engine for the test, as above 6000RPM my car hits the 103dB mark.
The PDF makes some "interesting statements... "Typical light vehicle engine output (kW) and torque Newton metres). (6 cylinder
3,300cc petrol engine). Source SAE 1993." Personally I wouldn't think that a 3.3L 200kw engine would be your "typical light vehicle".
Figure 9 is an interesting one where they compare different "big bore" exhausts on a 03 5.7L Commodore, and also give the noise difference and power increase from the different systems, biggest increase was from the loudest, and the 2nd quietist exhausts.
Figure 12 has info on how the ISO5130 test is done.
Anyway, I guess this is more of an FYI than anything.
