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Noisy vehicle
Your vehicle failed a warrant of fitness because of a noisy exhaust
Why is checking the exhaust noise part of the WoF inspection?
When your vehicle was manufactured it was fitted with an effective exhaust system, including a silencer. Exhaust gases produce a significant amount of noise. Silencers, as well as any catalytic converters, muffle this noise to an acceptable level. Governments specify the maximum noise levels that vehicles must not exceed when they are manufactured.
When the original exhaust system is modified, replaced or repaired, its effectiveness may be compromised, making the exhaust system louder than the one originally fitted by the vehicle manufacturer. A WoF inspection ensures that the vehicle’s exhaust system is checked regularly for noise output and meets the legal noise requirements.
What are the legal noise requirements?
Until now, an exhaust system was allowed to be noisier than the original exhaust system, provided it was not significantly noisier. As a result of public complaints about the number of noisy modified vehicles on the road, and the difficulty in assessing what ‘significantly noisier’ means, the government has introduced more stringent requirements relating to exhaust noise effective from 1 June 2008.
A vehicle will comply with the new law if the noise from the exhaust system is similar to or less than the noise from the exhaust system that was originally fitted when the vehicle was manufactured.
The exhaust system may be noisier than the original one provided that:
- the noise output either remains well below the legal noise limits, or
- an Objective Noise Test proves that the exhaust system does not exceed the legal noise limits.
How is exhaust noise checked during the WoF inspection?
The WoF inspector uses his/her experience to assess the noise output of the vehicle compared to other identical or similar vehicles in original and good condition.
If your vehicle is noisier than it was originally, it will fail its WoF unless it is able to pass a Noise Quick Check. If the WoF inspector has a hand-held noise meter he/she will use the Noise Quick Check to find out if the vehicle is well below the noise limits.
If your vehicle has failed its WoF because of a noisy exhaust, it may be referred to undergo an Objective Noise Test.
What is the difference between the Objective Noise Test and the Noise Quick Check?
The Objective Noise Test is a stationary tail-pipe noise test procedure based on international standards and can only be carried out by an approved low volume vehicle (LVV) certifier. If your vehicle passes the Objective Noise Test the LVV certifier will attach a label to the vehicle and issue a certificate. The cost of the test is about $130–200, depending on location. It is a one-off cost provided the exhaust system is maintained in good condition and is not modified further.
The Noise Quick Check procedure is a simpler and quicker version of the Objective Noise Test, making it suitable for WoF. It is used to assess whether the vehicle is well below the noise limits or referral for an Objective Noise Test is required. The Noise Quick Check can only be carried out by a WoF inspector who has an appropriate noise meter. A fee may be charged for this check.
What do I need to do to pass the WoF?
- Replace, remodify or repair the exhaust system so that the noise output is less than or similar to the noise output of the exhaust system that was originally fitted by the vehicle manufacturer, or
- Undergo an Objective Noise Test if you wish to have an exhaust system that is noisier than the original exhaust. However, you may still need to replace, remodify or repair the exhaust system to bring it below the legal noise limits. An Objective Noise Test is not required if the vehicle can pass the Noise Quick Check.
Should my vehicle get an Objective Noise Test even though it has passed the Noise Quick Check?
If your vehicle’s exhaust is louder than its original exhaust system and close to the permitted noise limit, then it is recommended that you have an Objective Noise Test carried out. By presenting the label and certificate to the WoF inspector you may avoid the inconvenience and cost of failing a WoF or having to go through a Noise Quick Check at every WoF inspection.
What are the noise limits?
In order to pass an Objective Noise Test, the vehicle must not exceed the following noise limits.
| Vehicle type | Maximun noise level (dBA) |
|---|---|
| Motorcycle or trike with an engine capacity of 125 cc or less | 96 |
| Motorcycle or trike with an engine capacity of more than 125 cc | 100 |
Light goods or passenger vehicle (eg, car, MPV, minibus, ute or van)
|
95 95 90 |
What if I disagree with the decision?
If you disagree with the decision to fail your vehicle, you should first try to resolve the issue with the inspecting organisation or the LVV certifier concerned. If you are still not satisfied, you may raise a complaint with Land Transport NZ, phone 0800 699 000, or download a complaint form.
Where can I get more information?
A list of approved LVV certifiers can be viewed on the Low Volume Vehicle Technical Association website: www.lvvta.org.nz
For more information about the law changes, refer to: www.landtransport.govt.nz/vehicles/objective-noise-test.html.
Page created: 7 May 2008