Want to make over your car with an exhaust system that thunders or a turbocharged engine?
Well, before you do, make sure it’s legal. Leigh Robshaw reports.
Phil Scott of Grafton has been modifying cars for 30 years and has been an RTA ‘engineering signatory’ — someone authorised to legally certify modifications — for 11 years.
The remaining portion of people are made up of those who modify their vehicles for commercial reasons, to accommodate disabilities or to convert them to motorhomes.
“NRMA doesn’t have a problem with people personalising their vehicles as long as it’s done safely and legally,” says Jack Haley, NRMA Vehicle Policy Specialist.
The RTA has strict guidelines on how vehicles can be modified in order to comply with the Australian Design Rules (ADRs) and classifies vehicle modifications as:
“Owner-certified minor modifications are generally those modifications which were optional equipment for the vehicle concerned, and some standard modifications of a minor nature which do not affect the level of safety, strength or reliability of vital systems such as brakes and steering,” says an RTA spokesperson. “These modifications have little or no impact upon the vehicle’s level of compliance with the Australian Design Rules.”
An example of owner-certified would be the Holden Commodore FE2; the manufacturer offers stiffer and lower suspension as an optional extra.
All major and minor modifications made to your vehicle or its equipment that affect registration details must be reported to the RTA to ensure accurate records are maintained.
If you’re caught with an illegal modification you’ll be slapped with a fine (from $78 to $104) and a defect notice. Unsafe modifications can also be detected at your annual inspection.
To find a list of engineering signatories recognised by the RTA to issue engineering certificates, visit the RTA website and type Vehicle Standards Information No. 15 in the ‘Search’ box.
Before you even think about modifying your car you should contact your insurance company as any changes you make — such as fitting tyres outside manufacturer’s guidelines — can affect your policy.
Graeme Adams, Head of Product & Underwriting, NRMA Insurance, says: “To ensure motorists are adequately covered [if] their car is stolen or they’re involved in a collision, they need to tell their insurance company — when they take out or renew their policy or modify their car — of any modifications made to their vehicle or accessories added.
“Certain modifications may put motorists at greater risk of having a collision — such as increasing the size of the engine and lowering or raising suspension. These sorts of modifications may in fact make the vehicle unroadworthy and impact [on] a motorist’s access to motor comprehensive insurance cover.
“Modifications which generally do not impact on insurance include airconditioning, tow bars, cruise control and tinted windows that meet registration requirements.”
The desire to fit alternative wheels and tyres is the most common modification.
“You can’t see a lot of... modifications, but wheels and tyres are very visual,” says Phil.
Changes to your car’s wheels and tyres can alter its behaviour on the road, so it is recommended you only fit wheels and tyres that are listed on the tyre placard or in your owner’s handbook, and always make sure your tyres are in good condition.
Tim Pomroy, NRMA New Vehicle Evaluation Specialist, says “Modifying wheels and tyres can improve a car’s road holding, but an incorrect tyre and wheel combination or a tyre [that is too wide] can affect the track of the vehicle and make it unroadworthy.”
The rumble of a hotted-up V8 as it thunders down the road makes a pretty loud statement. Enthusiasts can pay thousands of dollars to fit a larger exhaust system with the idea that it improves gas flow and derives more power from the engine.
“The whole aim is to reduce the restriction in the exhaust to maximise performance but the reality is it doesn’t deliver huge gains and it’s more about the noise than anything else,” says Tim.
Modified exhaust systems are popular in the 17–25 age group.
People say, ‘What’s the point of having a V8 if it doesn’t have the noise?’,” says Phil. “It’s partly an ego trip, partly personality and partly the show-off factor.”
The statutory limit for exhaust noise is 90 decibels for cars made after 1983, with fines ranging from $150 to $500 depending on how far the exhaust noise exceeds the limit.
Car enthusiasts modify seats for a few reasons: comfort, support, safety and aesthetics. But if you don’t know what you are doing, forget it. Unless you’re fitting seats that are optional extras for your vehicle, you’ll need an engineering certificate.
“If a seat is incorrectly fitted the potential for it to dislodge in the event of a crash would be increased,” says Tim. “Also, if you fit a new seat and it ends up too high or low, it could compromise the driving position of the car.”
“If your car has side airbags you shouldn’t modify your seats or use seat covers, as they could interfere with the deployment of airbags,” says Jack.
Engine modifications tend to be more complex and include either modifying the existing engine or fitting a new engine.
“Adding turbochargers, superchargers or after-market fuel injection systems are the most common modifications,” says Phil.
“There’s not a lot people can do these days to greatly increase the output of an engine short of spending thousands of dollars,” says Tim. “You can buy a powerchip, which is an after-market chip that goes into the vehicle’s engine management computer and changes the mapping of fuel and ignition timing to increase the peak power the car can put out, but it’s expensive and the net gain isn’t that great.”
The RTA says the only engine changes you can do without consulting an engineer are those where “the capacity increase is less than 15 per cent above the maximum size engine available for the vehicle, providing no major structural modifications are necessary and, where noise and/or exhaust emission ADRs apply, all standard equipment… relating to noise and emission control are retained and operate correctly”.
In other words, don’t modify the vehicle if it is likely to affect engine management, the catalytic converter, oxygen sensor or the mufflers in the exhaust system.
A few manufacturers provide an option to boost the power under the hood as an added extra. These include the Mini Cooper S, Subaru WRX, Holden and Toyota among others.
The State Government’s recent decision to restrict new P-platers from driving V8 cars included restrictions on turbo and super turbocharged vehicles. Though NRMA supports these restrictions, it has raised concerns with the Government about how it plans to enforce them on modified vehicles.
Modifications to the suspension with stiffer springs and shock absorbers and lowering it may improve handling, but a shoddy job can adversely affect the vehicle’s handling capacity.
here are strict regulations about how low you can go. Distance from centre headlight to ground must be 59 cm and there must be at least 10 cm of ground clearance under the car.
“A lot of cars come from the factory with a sports pack you can order and you can lower the suspension a bit and improve handling, but once you go outside the RTA’s and manufacturer’s guidelines, you run into problems, like a bumpy, unstable ride,” says Tim.
Tim advises 4WD owners not to raise suspension as it increases the high centre of gravity and the chance of a rollover.
Another trend is to put air bags or hydraulic bags in place of the springs. This allows the driver to control the car’s height from an interior switch that pumps up the bags to raise the car or deflates them to lower it.
The only suspension modifications the RTA accepts as owner-certified are the handling enhancing suspension components such as roll stabiliser bars and upgraded shock absorbers.
Installing a huge sound system is almost mandatory for many young drivers, and it is one modification you can do at home. If you own a sedan and want to cut holes for speakers in the rear parcel shelf be careful as you could inadvertently cut out the child restraint anchor point, which is against regulations.
The EPA says: “As a guide, if the sound can be clearly heard outside the vehicle and contains low frequency noise (eg doof music), it is likely to be offensive.”
If that sounds like your car, you could get a $150 fine and lose two demerit points if you’re caught.
Neon underbody accent lights that cast a surreal glow may be available for purchase, but it’s important to remember that strict laws govern the placement and colour of all car lights.
“Lights that are shaped or located in a way that causes confusion to other road users, or reduces the effectiveness of standard lights and reflectors fitted to the vehicle, are not permitted. This includes devices such as under body glow kits,” says an RTA spokesperson.
If you want more details on car modifications contact the RTA on 1300 137 302.
Hot rod, or street rod, modifications to vintage or classic cars still require an engineering signatory to approve modifications. Cars in their original condition may not conform to the Australian Design Rules, however, any modifications must be roadworthy and legal. Modifications are often made to improve the comfort of the car rather than its safety.
The Australian Street Rod Federation is the official body for street rodding in Australia. It liaises with state registration bodies and can advise on registration compliance.
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