Is a cat-back exhaust legal in Australia? The noise test explained.

Updated 30 October 2026.

A cat-back exhaust leaves your factory catalytic converter, oxygen sensors and on-board diagnostics exactly as they are, and with a Rog valved system, valves closed, your car sounds very close to stock around town. Valves open, it has the voice you chose for it. If you replace the front section too, our 200-cell sports catalytic converter keeps emissions control. Each system is built from your VIN, from a 3D scan of the chassis and of the original system, and bolts onto the original mounting points with no welding. Free technical documentation for your paperwork, a 3-year warranty and free delivery, with duties and taxes included in the price.

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Contents 6

1. At the noise test: how it works.
2. The rules, in short.
3. Find the exhaust for your car.
4. Frequently asked questions.
5. Write to us.
6. Sources.

At the noise test: how it works.

• A clear limit: 90 dB(A) for a car built after 1982 that is not certified to ADR 83/00, 96 dB(A) for an older one; for a car certified to ADR 83/00, no more than 5 dB(A) above the stationary noise level recorded at certification. NSW applies the same figures.
• Your figure in a minute: the NSW EPA notes that ADR 83/00 noise levels are published on the vehicle noise page of the Commonwealth Department of Infrastructure. Add 5 dB(A): that is your car's limit at the stationary test.
• No guesswork: a silencing device the driver can adjust, for example with in-car controls, must be designed so it can be tested fully opened. At the stationary test, the tester hears your exhaust at its fullest, against a figure you can know in advance.
• The method: the National Stationary Exhaust Noise Test Procedures for In-Service Motor Vehicles; under ADR 83/00, the stationary figure is measured with the microphone 0.5 m from the outlet, at 45 degrees.
• What a cat-back keeps: the factory catalytic converter, and mufflers the exhaust passes through, as the standards ask. It bolts onto the original mounting points.

The rules, in short.

Rog exhausts carry no certification of their own: that is a choice, because a certified system sounds almost like stock, and the valves give you both. The light vehicle standards, as set out in Queensland's Vehicle Standards and Safety Regulation 2021, ask every car to have a silencing device the exhaust passes through, and the same regulation bars driving a car whose exhaust has been modified in a way that reduces its effectiveness (the examples given are removing the diesel particulate filter or the silencing device); a cat-back keeps the catalytic converter and its mufflers. Each state or territory sets its own inspection and modification procedures (pink slip, roadworthy or safety certificate, depending on where the car is registered). For a sports catalytic converter, the rules depend on your state or territory; the catless version is for track use only.

In NSW, the EPA lists valves or other adjustable items among the devices not to be used in an exhaust, and permits an adjustable device fitted by the manufacturer when the car was built, or a replacement equivalent to it. If your car is registered in NSW, ask the EPA how it views your configuration before you order: the NSW EPA decides. Everywhere else, your state or territory decides.

Find the exhaust for your car.

Each product page shows the system, its options and its sound; each guide explains the configuration in detail. A few examples:

• Ford Mustang GT S550 (2018-2020): the exhaust and the guide.
• Ford Ranger Raptor V6 3.0: the exhaust and the guide.
• Subaru WRX VB: the exhaust and the guide.
• Volkswagen Golf 8 R: the exhaust and the guide.
• Toyota GR Supra A90 3.0: the exhaust and the guide.

Your car is not on the list? All our exhausts, by brand.

Frequently asked questions.

Valves closed, is my car quiet day to day?
Yes: valves closed, the sound stays very close to stock around town, and you open the valves when you choose. Your state or territory decides.

Is the noise test done with the valves open?
Yes: a silencing device the driver can adjust must be designed so it can be tested fully opened. The limit is 90 dB(A), or your car's ADR 83/00 figure plus 5 dB(A): the tester decides, for your state or territory.

Where do I find my car's ADR 83/00 figure?
The NSW EPA notes that ADR 83/00 noise levels are published on the vehicle noise page of the Commonwealth Department of Infrastructure. Add 5 dB(A): that is your car's limit at the stationary test. Your state or territory decides.

Will the system fit my car?
Yes: it is built from your VIN, from a 3D scan of the chassis and of the original system, and checked before production. It bolts onto the original mounting points with no welding, at the workshop of your choice.

What happens to my catalytic converter?
With a cat-back, it stays in place. If you also replace the front section, the 200-cell sports catalytic converter keeps emissions control, and the rules depend on your state or territory; the catless version is for track use only. Your state or territory decides.

Does Rog provide documents?
Yes: on request, we send you the technical documentation for your system free of charge, describing your configuration, for your registration authority or for your insurer. Your state or territory decides.

Write to us.

Email us at contact@rogmotorsport.com: we reply in writing, in English, within 24 hours. For instant answers: the Rog Advisor and our FAQ.

As set out in our terms and conditions of sale, it is up to each buyer to check the rules in their state or territory.

Sources.

1. Queensland, Transport Operations (Road Use Management, Vehicle Standards and Safety) Regulation 2021, section 20 and Schedule 1, sections 135, 137, 139 and 142, accessed 29 October 2026: https://www.legislation.qld.gov.au/view/whole/html/inforce/current/sl-2021-0114
2. Vehicle Standard (Australian Design Rule 83/00, External Noise) 2005, accessed 29 October 2026: https://www.legislation.gov.au/F2005L03523/2021-06-08/2021-06-08/text/1/epub/OEBPS/document_1/document_1.html
3. NSW EPA, vehicle noise (limits, adjustable devices), accessed 29 October 2026: https://www.epa.nsw.gov.au/your-environment/noise/vehicle-noise
4. NSW EPA, "Avoiding noisy vehicle exhaust" (adjustable devices, ADR 83/00 noise levels), accessed 29 October 2026: https://www.epa.nsw.gov.au/Your-environment/Noise/vehicle-noise/avoiding-noisy-vehicle-exhaust

The Rog team