Aftermarket components

Engine management systems

In modern vehicles the engine management system (computer) is an integral part of the emission control system.

Re-calibrating the engine management system either by changing the chip, re-programming, or replacing the unit with an aftermarket computer may result in non-compliance with the emission control Australian Design Rules (ADRs) applicable to the vehicle.

Testing a production vehicle for compliance with ADR emission control standards is a lengthy and expensive process and can only be undertaken with testing equipment acceptable to the Department for Infrastructure and Transport (DIT).

DIT may consider the fitting of an aftermarket engine management system where an engine upgrade takes place, however this will be on the condition that an IM240 emission test is performed.

An MR620 Application to Modify a Motor vehicle (891.8 KB PDF) must be submitted to Vehicle Standards.

Turbo-charging/supercharging petrol engine vehicles

Turbo-charging or supercharging an engine increases the power of the engine and may increase the exhaust emissions, fuel consumption and reduce the service life of the engine.

Passenger cars and passenger car derivatives (car type utilities and panel vans) manufactured prior to 1 July 1976 and fitted with petrol engines can be fitted with a turbocharger or supercharger to the original manufacturer's engine without DIT approval.

For cars manufactured on or after 1 July 1976 the fitting of a turbocharger or supercharger requires one of the following:

  • the vehicle is fitted with a Second Manufacturer's plate to demonstrate compliance with all Australian Design Rules
  • the vehicle to pass an IM240 emissions test
  • the converted vehicle is identical to the production turbo/supercharged vehicle.

In all cases a statement of requirements is required and the vehicle must pass a roadworthiness inspection.

Certification from a professional engineer may also be required. See the list of qualified engineers recognised by DIT -  MR426 Chartered Professional Engineers (438.4 KB PDF).

Turbo timers

Turbo timers are not to be fitted to vehicles manufactured on or after 1 January 1972.

Australian Design Rule 25 (Anti-Theft Lock) requires that the normal function of the engine only occurs when the ignition lock is in the engine 'on' position.

Turbocharger boost controllers

Alteration to an engine's turbo boost pressure is not acceptable. This is specified and set by the vehicle manufacturer to ensure compliance with the Australian Design Rules.

Blow-off valves

Fitting an aftermarket blow-off valve can affect the vehicle's compliance with the exhaust emission requirements specified in the Australian Design Rules, and is therefore not acceptable.

External wastegates on turbocharged engines are not permitted.


Intercoolers can be fitted to vehicles providing:

  • there are no sharp projections ahead of the front bumper that may increase the risk of injury to other road users, including pedestrians
  • the intercooler is fitted and secured in a manner in accordance with normal automotive engineering practices, and the structural integrity of the vehicle has not been affected
  • adequate provision is made for a complying number plate to be fitted in an approved position.

Oil 'catch cans'

An oil catch may be fitted provided it is vented back into the vehicle's crankcase so that oil or fumes do not escape to the atmosphere.

Venting any engine emissions to the atmosphere is not permitted.

Steering wheels

Steering wheels are an important component in the safety of your vehicle. They are designed to minimise injury to the driver during a vehicle collision.

If you fit a steering wheel you must make sure that it complies with Australian Design Rule (ADR) requirements.

Replacement steering wheels must be not less than 330 mm in diameter.

If the original steering wheel was designed with a recessed or padded hub, the replacement wheel must be of a similar design.

A non-standard aftermarket steering wheel may be fitted to passenger cars and derivatives manufactured prior to 1971.

When selecting a replacement steering wheel, ensure that it is firmly padded and is constructed so that it will bend on impact without splintering or cracking, and that no parts of the wheel are loose or cracked.

Passenger vehicles built after 1970 must comply with ADR 10 (Steering Column). The replacement steering wheel must have the appropriate markings indicating that it complies with ADR 10.

There are a number of steering wheels certified to ADR 10, so prior to purchasing an aftermarket steering wheel, contact Vehicle Standards to ensure that it is acceptable.

Passenger vehicles manufactured after June 1995, that are required to comply with ADR 69/00 (Full frontal impact occupant protection), may only be fitted with steering wheels certified by the vehicle manufacturer as suitable for that vehicle.

For example, if your vehicle has an airbag steering wheel as standard, the replacement must be the same.

Fitting an aftermarket steering wheel to a vehicle that has an airbag in the original steering wheel is not acceptable.

Fibreglass or carbon fibre panels

The use of custom made fibreglass or carbon fibre body panels is acceptable provided that the structural integrity of the body is not adversely affected and the vehicle continues to comply with all relevant Australian Design Rules.

When fitting a carbon fibre bonnet, it must be manufactured in a way that it:

  • is of equal strength to the original
  • retains the under-bonnet ribbing/structure
  • is mounted using the original bonnet catch and hinges.

Spoilers and wheel guard flares

Cosmetic body modifications such as wheel guards, side skirts and front or rear spoilers are permitted without approval provided that they are fitted with regard to the safety of other road users.

Front spoilers must meet ground clearance requirements of 100 mm. It is recommended that the airflow for the brake cooling is not adversely affected.

Rear spoilers must be within the original body profile of the vehicle.

There must not be any sharp edges that could increase the severity of injuries to pedestrians and other road users. See also the document MR800 Hazardous Projections (1.3 MB PDF).

The fitting of a rear spoiler that incorporates a brake light requires any originally fitted equipment eye-level brake light to be disconnected.

Contact DIT Vehicle Standards

Related information

Other websites

Australian Design Rules - Commonwealth Department for Infrastructure and Transport


Road Traffic (Light Vehicle Standards) Rules 2018

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Page last updated 17 December 2021

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