Modifying a car

Car body	Horn	Engine reconditioning
Exhaust	Lighting	Suspension
Tyres & wheels	Window tinting	Engine modification
RAC Motoring Advice	RAC Vehicle Inspections	Department for Planning and Infrastructure

Modification rules  

All modifications must be approved by the Department for Planning and Infrastructure - Vehicle Licensing.

• The vehicle will need to be examined. 
• The modified vehicle must comply with the Australian Design Rules, the Road Traffic Vehicle Standards Regulations 2002 and the Road Traffic Vehicle Standard Rules 2002.
• If you do not have DPI approval for your modification, your vehicle may be issued with a defect order, you could be fined or your vehicle de-licensed.
• Be aware of what you can and can not do, as ignorance of the law is not a valid defence.
• If you modify your vehicle and don't tell your insurance company about the modifications you have made, your insurer may be able to cancel the policy or avoid paying a claim which you make.
• If your car is under warranty and you modify your vehicle, you may void your warranty.

Bullbars

If you are contemplating having a bull bar fitted to your vehicle there are some important issues to be considered.

• Legal requirements: 
  • Any object or fitting, not technically essential to the vehicle, that protrudes from any part of the vehicle in a manner likely to increase the risk of bodily injury to a person is prohibited under the Road Traffic (Vehicle Standards) Regulations 1977.
  • The above regulation also prohibits objects that are sharp or pointed and any object or fitting unless its design, construction and condition and the manner in which it is fitted to the vehicle is such as to reduce to a minimum the risk of bodily injury to a person.
  • If you are buying from a reputable dealer then the bull bar should already conform to these regulations.
• Construction:
  • Steel bull bars are heavy and the vehicle often requires suspension modifications to take the extra weight.
    • They are strong and if you need to fit a big winch then steel may be an option.
    • Besides the weight problem, the other disadvantage of steel bars is that they are prone to rusting if abused.
    • Rust will weaken the bull bar and this may be dangerous in the event of an accident.
  • Alloy and aluminium bull bars are the most popular bars.
    • They are lighter than steel bars and they are not prone to rusting.
    • Most modern alloy bars are very strong and are capable of winching relatively large loads, but if you intend using the winch a lot then check with the bar manufacturer as to its suitability.
  • If you are not considering fitting a winch then a plastic bull bar is worth contemplating. They are durable and quite popular with some lobby groups as their construction is designed to lessen the impact in an accident
• Fit:
  • It is essential to have your bull bar mounted correctly, particularly if your vehicle is fitted with airbags.
  • Some bars are mounted to the chassis of the vehicle using the original bumper and others replace the front bumper.
  • If your vehicle is fitted with airbags then you must first check with the vehicle manufacturer to confirm that a bull bar can be fitted as it may negate any warranty outstanding on the vehicle.
  • All modern vehicles have crumple zones in the chassis, which are essential to the airbag operation. The fitment of a bull bar can affect these crumple zones.
  • Most bull bar manufacturers supply impact-absorbing mounts to overcome this problem.
• Needs:
  • If the majority of your driving is in the city then you probably don't need a bullbar, as they are designed to protect the vehicle and its occupants against straying animals on country roads.
  • If you are driving predominantly in country areas then you may need to consider purchasing a bull bar.

Car body

• There are regulations that must be adhered to.
• You must not contravene the Australian Design Rules or the Road Traffic (Vehicle Standards) Regulations 1977, which set down standards for vehicle design and use.
• Some of the things you need to be aware of are:
  • Licence plates on the front and rear of the vehicle must be fitted no more than 1.3 metres from the ground.
  • Bonnets or movable body panels forward of the windscreen must be fitted with a latch system. Any panels that open from the front, which when open partially or completely obstruct the driver's vision must also have a second latch system.
  • Side doors on the vehicle must comply with Australian Design Rule No-29 for strength. Using lightened doors may compromise the strength.
  • If your vehicle is fitted with a tray and used to transport loose materials or small objects it must be fitted with front, side and tail boards capable of preventing the load from falling from the vehicle.

Horn

It is compulsory to have a horn or audible warning device fitted to your vehicle in order to give sufficient warning of your presence.

• The horn must produce a single tone or frequency, so any device that produces a varying tone or frequency is not allowed under the Road Traffic (Vehicle Standards) Regulations 1977.
• This regulation does not apply to an anti-theft device (car alarm) that emits a varying tone when triggered by an attempted theft or interference with the vehicle.

Engine reconditioning

The question of whether you have your engine reconditioned or just change the car is a difficult one to deal with, as it depends on how much you are willing to spend and what your expectations are. Engine reconditioning is expensive and you have to remember that only the engine has been reconditioned, the other components: transmission, suspension, brakes and all the ancillary systems are going to be worn to a certain extent. You need to know what you are getting. 

• Fully recondition existing engine:
  • In this case your own engine is dismantled and assessed for suitability for reconditioning.
  • The parts are cleaned, examined for durability and measured for wear.
  • Parts, which are outside acceptable tolerances, are replaced.
  • If you've been replacing components on your engine as they've been required, you may find that this is a cheap option.
• Buy a reconditioned engine:
  • This is much the same as the previous option, but the down time will be less. 
  • Standards Australia has issued a code of practice for reconditioning engines (AS 4182- 1994).
  • A good engine specialist will be aware of this standard and will build his engines to this specification.
  • When buying a reconditioned engine you will be given two options.
    • The first is what's called a "long motor", which is the engine complete with sump and cylinder head.
    • The second is a "short motor", which is the engine minus the sump and cylinder head.
  • The initial price for the job will be for an engine plus the labour to fit it. 
  • There will be other costs involved.
    • The cooling system hoses may need to be replaced.
    • The radiator will probably need to be serviced.
    • The clutch, fan belts, water pump and other items may need attention.
    • This can add more than a thousand dollars to the bill.
  • The engine specialist will not be able to determine all the parts required until the engine is dismantled, so be prepared for the extra cost.
• Service existing engine:
  • This is one of the cheapest options but you must be aware that you are not getting a reconditioned engine.
  • Only the worn parts are replaced.
  • Iitems like the oil pump, pistons and valves will not be changed.
  • Usually the cylinder bore is honed and the piston rings are replaced as well as the big end and main bearings. T
  • he cylinder head will also be serviced, which means that the surface will be machined, the valves reground and the valve stem seals replaced. 
• Buy a second-hand engine:
  • The cheapest option, but one that is filled with pitfalls.
  • You really need to know the history of the engine:
    • How many kilometres the engine has travelled?
    • What its service history is like and can it be verified?
    • Has it been overheated?
    • Was the engine burning oil?
    • Why is it for sale?
• More information on engines.

Exhaust

One of the first and probably the cheapest modifications you can make to your car is to fit a bigger (noisier) exhaust.

• Exhaust manufacturers will cite increased power as a reason to change your exhaust system.
• Be mindful of the fact that the manufacturer has already spent millions of dollars designing your vehicle to perform at its best and simply bolting on a muffler or a bigger diameter exhaust pipe may not give you a noticeable increase in performance.
• Before you start to modify your exhaust system it would be a good idea to check on what is actually allowed under the Road Traffic (Vehicle Standards) Regulations 1977.
• All cars when first registered in Australia must comply with Australian Design Rule 28 or 28 A with regard to vehicle noise.
• This rule sets the vehicle exhaust noise standard.
• The standard for passenger cars is 81 decibels (dB(A)) and 82 dB(A) for off-road passenger vehicles.
• More information on exhaust systems.

Lighting

• Extra driving lights:
  • You can fit two extra driving lights to the front of the vehicle, no higher than 1.4 metres from the ground.
  • Lights must show a white light only and project a main beam in front of the vehicle.
  • One extra driving light in line with the centre of the vehicle can be fitted.
  • The additional lights must extinguish when the headlamps are dipped and they must be capable of being extinguished separately.
• Fog lights:
  • Two fog lights of equal power to the front of the vehicle at equidistance from the centre line of the vehicle and an equal height from the ground can be fitted.
  • The centres of the lamps must be not less than 600 millimetres apart.
  • Or one fog light in the centre of the vehicle with 2 lamps of a power not exceeding 7 watts, symmetrically fitted to the front of the vehicle, at an equal height from the ground and not less than 1.1 metres apart.
  • The fog lamp should be capable of showing a white or amber light, the beam must be deflected downwards or both downwards and to the left.
  • The centre of the fog light should be no higher than the centre of any headlamp or alternative lamp (extra driving light) fitted.
  • The fog light can only be used under abnormal weather conditions and cannot be used with any other lamp exceeding 7 watts.
  • If a single fog light is alight then it must be used with two lights not exceeding 7 watts.
• Searchlights: 
  • Search or spotlights can be fitted to vehicles but can only be lit when the vehicle is stopped.
  • The searchlight cannot project any more than 7 metres from the lamp.
• Reverse lights:
  • No more than two extra lights may be fitted in addition to the normal rear lights on a car.
  • They can only be lit when the vehicle is reversing.
  • The lights must be white or amber in colour and the maximum height of the lights must not exceed 1.1 metres.
  • When two lights are fitted they must be of the same colour and symmetrically fitted.
• Wiring:
  • When wiring additional lights always use cable of a suitable size and quality.
  • Solder all joints where possible and insulate with suitable material.
  • Keep wiring away from moving parts, the fuel system or anything that can cause overheating.
  • Support the cable every 600 millimetres and protect from chaffing by using rubber grommets where the cable passes through the vehicle's bodywork.
• Light fittings:
  • Headlamp guards are great for protecting from stone chips, but keep in mind that any fitting that deflects or obscures the lights is illegal. 

Suspension

Modifying suspensions is a popular way of enhancing the look of a car and improving its handling characteristics.

• By lowering the suspension, the centre of gravity of the vehicle is lowered and this enhances handling.
• Vehicles are generally raised to increase the load carrying capabilities.
• There are guidelines that should be observed when modifying suspensions.
• The vehicle’s bodywork should be no lower than the lowest part of the wheel rim.
• The Road Traffic (Vehicle Standards) Regulations 1977 state that the centre of the headlamps can be, not less than 600 millimetres from the ground. Lowering the suspension on the front or jacking up the suspension at the rear can affect the headlamp height.
• Lowering the suspension can cause the tyres to come into contact with the bodywork and upset the steering geometry.
• Fitting of suspension components, which are available, as options from the vehicle manufacturer for the particular model are acceptable.
• Modifications, which substantially change the steering geometry or affect the load bearing capabilities of the vehicle, are not allowed.
• Remember that any modifications or alterations to the vehicle must be examined and passed by the Department for Planning and Infrastructure and a modification permit must be issued.

Tyres & wheels

When modifying the wheels and tyres on your car you need to be mindful of a number of rules.

• Tyres should not:
  • Protrude past the mudguards.
  • Foul on any of the bodywork or any vehicle component when locked from side to side.
• The tyre load rating must meet or exceed the manufacturer's specifications.
• The manufacturer's specified vehicle track must not be exceeded by more than 25mm.
• The rim should be no lower than the lowest part of the vehicle.
• Using low profile tyres outside of the manufacturer's recommendation can cause the speedometer to read inaccurately and this can lead to speeding fines.
• Incorrect tyres can also affect the fuel consumption and performance of the vehicle.
• When modifying wheels and tyres always refer to the manufacturer's recommendation on the tyre placard.
• Going outside of this recommendation can invalidate any warranty outstanding on the vehicle and also render the vehicle unroadworthy.
• More information on tyres.

Window tinting

The Road Traffic Vehicle Standards Rules 2002 place a number of restrictions on window tinting on vehicles:

• The windscreen must not be tinted apart from a band at the top of the windscreen, which must not exceed more than 10% of the windscreen depth or below the sweep of the wipers whichever is greater.
• The tint on side or rear windows should not be darker than 35% visible light transmission (VLT), i.e. at least 35% of the available light should pass through the window.
• Tinting must not be mirror like, as this can be a hazard to other road users and must not reflect more than 10% of the incident light.
• If you intend to have your car windows tinted you should make sure that legal limits are not exceeded.

Engine modification

Make a decision about what you expect from your vehicle's engine: 

• Race engine.
• Good low-down torque.
• Good top-end torque.
• Streetcar or racer.
• An engine that is designed and modified to be an out and out racer will not function very well in normal urban driving situations.
• Check that any bolt on components have been certified to retain compliance with Australian Design Rules.
• There are many engine repairers specialising in modifications to particular models.
• Modifications that increase the engine power output will probably increase the fuel comsumption and reduce engine life.
• If you disconnect or modify the engine emission control system, the engine will need to be recertified.
• All pipes and tubing must be properly secured.
• The exhaust noise level must not exceed the original manufacturer’s specification.
• You must inform your insurance company of any modifications you make.
• More information on engines.