Are you allowed to drive without a muffler?

You can drive a car or motorbike with no muffler as long as it doesn’t exceed the maximum sound level allowed.

What is a muffler?

A muffler is part of the exhaust system which reduces the volume of your engine to an acceptable level. The muffler dampens the noises coming from the engine. If you take the muffler off, the engine will sound much louder.

Why would you modify your exhaust?

All new vehicles comply with the sound levels in New Zealand. A problem arises when an owner wants to modify their exhaust. The exhaust could be modified to:

• Improve power (or reduce power losses)
• Change the type of sound it makes
• Accommodate other modifications

These will usually increase the volume of the noise coming out of the exhaust. Noise is measured in decibels (dB). The maximum decibel levels for different types of vehicles are:

Vehicle type	Maximun noise level (dBA)
Motorcycle or trike with an engine capacity of 125cc or less	96
Motorcycle or trike with an engine capacity of more than 125cc	100
Light goods or passenger vehicle (eg, car, MPV, minibus, ute or van) first registered in NZ before 1 June 2008	95
Light goods or passenger vehicle (eg, car, MPV, minibus, ute or van) first registered in New Zealand on or after 1 June 2008, and: manufactured before 1 January 1985 manufactured on or after 1 January 1985	95 90

Every 10dB, the perceived loudness doubles, therefore a 600cc motorbike at maximum volume can legally be twice as loud as a 5-litre V8 from 2007.

Some vehicles come with factory-optioned sports exhausts which are louder than standard exhausts, but they still must not exceed the limits posted above.

There are exceptions to the rule which you can find in the LVVTA noise emission standards guide.

Getting an objective noise test

If you have modified your car or motorbike and it is different from the factory setting, even if you pass a WoF’s quick noise test, you can get an objective noise test to get a certificate to prove that your vehicle’s volume falls within the maximum limits. This is a good idea otherwise you might be pulled over by the police and given a green or pink sticker or you may find your vehicle fails the Warrant of Fitness. If you do get a green or pink sticker because of noise your vehicle will have to pass the objective noise test.

An objective noise test is a stationary tail-pipe noise test based on international standards. You’ll need to go to an approved low volume vehicle (LVV) certifier. If it passes the test, the certifier will attach a label to your vehicle and will issue a certificate. It’s a one-off test and doesn’t need to be repeated unless you modify the exhaust further.