Correct as at 17th April 2024. It may be superseded at any time.
Extract taken from: Vehicle Inspection Portal > VIRMs > In-service certification (WoF and CoF) > General vehicles > Exhaust
11 Exhaust
11-1 Exhaust system
Reasons for rejection
Mandatory equipment
1. A vehicle is not fitted with an exhaust system that includes a means of sound reduction (Note 1) (Note 6).
2. A light vehicle is presented for a WoF or CoF because it has been ordered off the road (pink- or green-stickered) by an enforcement officer for non-compliant exhaust noise, and there is no evidence that the vehicle has passed an LVVTA objective noise test since the vehicle was ordered off the road (Note 4), ie:
a) the owner cannot produce a valid objective exhaust noise emissions test certificate (Figure 11-1-1) issued after the vehicle was ordered off the road (Note 5), and
b) the exhaust system tail pipe is not fitted with a valid LVVTA noise test label (Figure 11-1-2).
Condition
3. An exhaust system is not securely mounted.
4. The exhaust system is so constructed or modified that its operation or effectiveness can be readily interfered with, eg the driver is able to interfere with the exhaust system by operating a manual switch, or the exhaust is fitted with a flame thrower kit.
5. The exhaust system is so constructed that emitted heat or fumes:
- are not directed away from, and prevented from entering, the vehicle’s passenger compartment (Note 7), or
- are likely to harm vehicle occupants.
See also (Note 6) regarding screamer pipes.
Performance
6. There is a leak of exhaust fumes from the exhaust system.
7. The exhaust noise output from a class LE, MA, MB, MC, MD1, MD2 or NA vehicle (other than a class MA or MC motorsport vehicle with a valid motorsport authority card) is not less than or similar to the noise output the vehicle (or a vehicle of a similar type (Note 2)) would have had when it was manufactured with its original exhaust system, and:
a) the increased noise output exceeds the relevant noise limit in Table 11-1-1 when assessed by the vehicle inspector:
i. using their own experience, or
ii. using the Noise Quick Check specified in Technical bulletin 1, or
b) there is no evidence that the vehicle has passed an LVVTA objective noise test, ie:
i. the owner cannot produce a valid objective exhaust noise emission test certificate (Figure 11-1-1), and
ii. the exhaust system tailpipe is not fitted with a valid LVVTA noise test label (Figure 11-1-2).
Note 1
Exhaust system means a pipe assembly through which the engine exhaust gases pass to the atmosphere and includes some means of sound reduction such as a silencer or resonator.
Note 2
For the purpose of Reason for rejection, a vehicle of a similar type means a vehicle of similar age, vehicle size, body type, engine size and power output, and may be of a different make and model.
Note 3
The noise limits in Table 11-1-1 are lower than the noise limits specified in legislation, and considered to be ‘clearly below’ the legal noise limits. Vehicles with an exhaust noise output clearly below the legal limits do not require an Objective Noise Test.
Note 4
A new objective noise test is required every time the vehicle is ordered off the road for non-compliant exhaust noise, even if the vehicle is presented for WoF or CoF with a quieter or original exhaust system.
Note 5
Sight the ordering off the road notice or phone the NZ Police to find out when the ordering off the notice was issued.
Note 6
Externally venting wastegates (screamer pipes) are not permitted and cannot be certified as they are not adequately muffled and the exhaust gasses do not exit behind the passenger compartment. However, wastegates that feed gasses into their own muffled exhaust system exiting behind the passenger compartment, or feed gasses back into the vehicle’s exhaust system, are permitted.
Note 7
Exhaust systems that direct exhaust fumes away from the perimeter of the vehicle’s passenger compartment will comply with this requirement, and an OE fitment (or direct OE replacement) where the exhaust system terminates directly below the vehicle’s floorpan is also permissible.
Table 11-1-1. Noise limits for the Noise Quick Check
( see Note 3)
| Vehicle | Noise limit (decibels) (Note 3) |
|---|---|
Class LE with an engine capacity of 125 cc or less | 93 dBA |
| Class LE with an engine capacity of more than 125 cc | 97 dBA |
| Class MA, MB, MC, MD1, MD2, NA first registered in New Zealand before 1 June 2008 | 92 dBA |
Class MA, MB, MC, MD1, MD2, NA first registered in New Zealand on or after 1 June 2008 and: – manufactured before 1 January 1985 – manufactured on or after 1 January 1985 | 92 dBA 87 dBA |
Figure 11-1-1. Objective exhaust noise emission test certificate
Figure 11-1-2. Objective noise test label
Summary of legislation
Applicable legislation
Mandatory equipment
1. A vehicle with an internal combustion engine must be fitted with an exhaust system (Note 1) (Note 6).
2. A vehicle that is presented for a WoF or CoF because it has been ordered off the road by an enforcement officer for non-compliant exhaust noise must pass an LVVTA objective noise test before the vehicle may be issued with a WoF or CoF (Note 4).
Condition
3. An exhaust system must not be constructed or modified in a way that allows a person to interfere readily with its operation or reduce its effectiveness.
4. An exhaust system must be designed, constructed, positioned and maintained in a way that minimises the risk of heat or fumes emitted from the system harming the vehicle’s occupants.
Performance
5. An exhaust system must be effective and in good working order.
6. The noise output from the exhaust system of a class LE, MA, MB, MC, MD1, MD2 or NA vehicle (other than a class MA or MC motorsport vehicle with a valid motorsport authority card):
a) must be less than or similar to the noise output from the vehicle’s original exhaust system at the time of the vehicle’s manufacture, or
b) must not, if the noise output of the vehicle’s original exhaust system at the time of the vehicle’s manufacture is not known, exceed the applicable maximum decibel level when tested and certified by an LVV specialist certifier in accordance with the LVVTA objective noise test.
Modification
7. A class LE, MA, MB, MC, MD1, MD2 or NA vehicle that has been modified so as to increase its exhaust noise output must have the exhaust system inspected, tested and certified by an LVV specialist certifier as having passed the LVVTA objective noise test, unless:
a) the increased noise output is clearly below (Note 3) the applicable noise limits, and
b) the vehicle has been inspected in accordance with the requirements in this manual, including those for equipment, condition and performance.
8. When a vehicle has been certified by an LVV specialist certifier as having passed the LVVTA objective noise test:
a) the owner must produce a valid objective exhaust noise emissions test certificate (Figure 11-1-1), and
b) the exhaust system tailpipe must be fitted with a valid LVVTA noise test label (Figure 11-1-2).
Page amended 1 October 2020 (see amendment details).
11-2 Exhaust emissions
Reasons for rejection
Performance
1. A vehicle with the engine at normal operating temperature (Note 1) emits clearly visible smoke (Technical bulletin 8) from the exhaust tailpipe (Note 2):
a) for a continuous period of five seconds when the engine is idling and does not meet the additional requirements in Table 11-2-1, or
b) as the engine is being rapidly accelerated to approximately 2500rpm or approximately half the maximum engine speed (whichever is lower) and does not meet the additional requirements in Table 11-2-1.
2. A vehicle (other than group L vehicle or a class MA or MC motorsport vehicle with a valid motorsport authority card) that was first registered in New Zealand on or after 1 May 2010 and manufactured from 1 January 1990 has a catalytic converter (or diesel particulate filter (DPF) in the case of diesel powered vehicles) removed where there is evidence that one was originally fitted, and there is no written evidence issued by an entry certifier that the vehicle passed a prescribed metered emissions test in this condition (Note 5) (Note 6) (Figure 11-2-1).
Note 1 Test procedure:
a) Carry out the idling and acceleration tests in Reason for rejection 1. A vehicle that passes both tests with the engine below normal operating temperature is deemed to have passed with the engine at normal operating temperature.
b) If the vehicle has failed either test, ensure the engine is at normal operating temperature. Then purge the system by increasing the engine speed to 2500 rpm (or half the maximum engine speed if this is lower) and holding it there for about 5 seconds. Repeat the idling and acceleration tests in Reasons for rejection 1.
Note 2
Visible emissions caused by the condensation of water vapour do not count as smoke.
Note 3
Acceptable evidence is:
a) a letter on the letterhead of the manufacturer or manufacturer’s representative, or
b) a letter on the letterhead of an appropriate automobile club, or
c) evidence of equal authority to (a) or (b) above, eg from an appropriate expert.
Note 4
The vehicle inspector may need to take into account further information about unusual or older vehicles, eg from an appropriate expert such as an office holder in a vintage car club.
Note 5
This reason for rejection does not apply if the vehicle operator can provide evidence that the vehicle was first certified for entry before 1 May 2008.
Note 6
The metered emissions test can only be carried out at entry certifier sites (VTNZ, VINZ, NZAA) where entry inspections are carried out. The entry certifiers will issue a document (Figure 11-2-1) that identifies the vehicle, whether or not the vehicle has passed the test, and whether or not the vehicle was tested with any OE catalytic converters removed. A metered emissions test is not required if a catalytic converter is refitted, or if there is evidence that the vehicle was not originally fitted with a catalytic converter.
Table 11-2-1. Additional requirements
Type of vehicle | Additional requirements |
|---|---|
First registered on or after 1 January 1960 with four-stroke engine, or First registered before 1 January 1960with four-stroke engine manufactured on or after 1 January 1960. | 1. Document produced by the vehicle operator that proves that (Note 3): a) the engine is original equipment for the vehicle, and b) its design means that the vehicle cannot reasonably comply with the visible smoke emission requirements. Note No evidence is required if, during the acceleration test, a diesel-powered vehicle emits moderate smoke caused by turbo lag. 2. The smoke produced is not noticeably and significantly more visible than it would have been when the vehicle was manufactured and supplied with the fuel recommended by the manufacturer. |
First registered before 1 January 1960 with four-stroke engine manufactured before 1 January 1960, or Vehicle with two-stroke engine or rotary engine. | The smoke produced is not noticeably and significantly more visible than it would have been when the vehicle was manufactured and supplied with the fuel recommended by the manufacturer (Note 4). |
Figure 11-2-1. Exhaust emissions test certificate
- Download a copy of the Exhaust emissions test certificate.
Summary of legislation
Applicable legislation
Performance
1. A motor vehicle must not emit clearly visible smoke (Note 2) when the vehicle’s engine is running at its normal operating temperature, under either of the following conditions:
a) for a continuous period of five seconds when the engine is idling
b) as the engine is being accelerated rapidly to approximately 2500 revolutions per minute or approximately half the maximum engine speed (whichever is lower).
2. Requirement 1 above does not apply if the driver of the vehicle produces documentation that proves that the engine is original equipment for the vehicle and the engine’s design means the vehicle cannot reasonably comply (Note 3).
3. The exhaust emissions system or exhaust control equipment of a vehicle (other than a group L vehicle or a class MA or MC motorsport vehicle) first certified for entry into service on or after 1 May 2008 and manufactured on or after 1 January 1990 must not be modified so as to prevent the vehicle from being able to pass a prescribed metered emissions test.
Technical Information
Page amended 2 December 2019 (see amendment details).