$250 + GST

The vehicle is inspected and the ADRs and other relevant literature are consulted to determine the required actions. If supplementary modifications are required in order that the vehicle meets the intent of the ADRs and the Code of Practice for Light Vehicle Modifications, they are recommended to the vehicle owner.

A typical preliminary inspection may involve examination of modified components, measurements and photographs, and a stationary noise test.

Note: Off-site inspections incur an additional $100 + GST (Sydney Metropolitan area)

$100 + GST

If recommendations were made during a preliminary inspection, a further inspection is required to confirm that the changes meet the intent of the ADRs and the Code of Practice for Light Vehicle Modifications.

Note: Off-site inspections incur an additional $100 + GST (Sydney Metropolitan area)

$150 + GST

Once inspections reveal that the vehicle meets all relevant ADRs, an Engineering Certificate can be prepared and issued to the owner.

$50 + GST per ½ hour

Most engine and chassis modifications require further assessment with calculations. Typical calculations include: required brake system dimensions; wheel diameter comparison, side intrusion bar strength.

These calculations are charged in half-hour increments. As a guide, wheel diameter comparison calculations usually take about a half-hour and side-intrusion bar strength calculations take approximately 2 hours.

$80 + GST per ½ hour

Complex static and dynamic structural assessments are carried out with the aid of Finite Element Analysis to reduce calculation time. Modelling is charged at $80 per half-hour block. Problems which require more than 12 hours of processing time are further charged at an agreed rate.

Finite Element Analysis may be used to verify structural modifications to chassis, suspension and steering components if hand calculations are limited.

$120 + GST

A stationary noise test is conducted as part of preliminary inspection for imported vehicles and when modifications to the engine and ancillaries have been made. A stationary noise test may also be required as part of further inspections if the vehicle failed the test prior. If you do not need a certificate but would like to measure the sound intensity of your exhaust we can perform an independent Stationary Noise Test (Contact exhaust manufacturers to conduct testing on typical systems).

$250 + GST

The vehicle’s acceleration, braking and cornering capabilities are measured using a three-axis accelerometer. A short report is prepared as part of the engineering certificate. We always perform a Dynamic Vehicle Assessment for engine, suspension or brake modifications.

- Wheel size changes

- Collapsible steering wheel boss

- Custom exhaust systems

- Dashboard-mounted tachometers

- Engine modifications

- Suspension modifications

- Brake system modifications

- Import approval for imported vehicles

- Weighbridge certificate (for buses, utes, campervans and imported vehicles)

- Dynamometer chart (for engine modifications)

- Any other useful information you may have, including workshop manuals, and brochures of aftermarket components

Engine

Engine replacement, fitment of super/turbocharger, modified exhaust

Drivetrain

Replaced gearbox, axles and differentials, generally in conjunction with engine modifications.

Brakes

Upgraded brake systems including upgrade kits, modified brake systems for power, weight and weight bias changes

Steering

Replaced steering columns in restorations, replaced steering rack for different ratio or power steering modification, changes in response to increased wheel loads

Suspension

Upgraded and replaced spring and damper units, replaced suspension components for additional adjustability, lowered ride height, changes in response to other modifications

Seating

Bucket/racing seats, seat belts and anchorages

Body

Convertible modifications, stretch conversions

Wheels and tyres

Wider tyres, larger diameter wheels, changed speed/load rating in response to other modifications

When modifying a vehicle it is important to consider all aspects of the vehicle and how the changes will affect the vehicle. Production cars are required to satisfy all Australian Design Rules (ADRs) simultaneously, which is achieved by very subtle and careful design of all aspects to ensure this.

In many cases vehicles designed to pass the ADRs have not been given a very wide margin on the rules. Vehicles will sometimes undergo dozens of minor design changes in response to failing a particular ADR. This is also because the design change has the capacity to change some compliance aspect of another ADR.

When modifying a vehicle is it very likely the modification will impact compliance over some of the ADRs the vehicle was designed to pass, sometimes over ADRs seemingly unrelated to the change.

The engineering certification system is in place to ensure modified vehicles do not overly compromise the entire vehicle integrity with respect to ADRs and also to maintain reasonable handling and control requirements, as the ADRs are primarily safety implements. Since a full analysis often requires reengineering the entire car, a more feasible set of requirements known as the Code of Practice for Light Vehicle Modification along with a cache of bulletins posted by the RTA are used to assess a modified vehicle. These offer a scope within which engineering signatories are permitted to certify modifications and ensure any deviation from ADR compliance is minimal and does not jeopardize the safety of the original vehicle

Typically a vehicle is designed by the manufacturer to have suitable handling, comfort, reliability and safety, simply to ensure the car is marketable. The ADRs are in place since the safety of a vehicle is not particularly apparent from inspection, unlike other more obvious characteristics of comfort and handling and any poor reliability results.

In addition to careful design for ADR compliance, vehicles are designed to balance power, handling, braking, reliability, weight and many other less critical aspects including noise and vibration. By making a modification to the vehicle any of these parameters can be changed drastically and sometimes unpredictably.

Human Impact Engineering supports vehicle modifiers in making legal and safe modifications to vehicles, however we focus on complete modifications that consider all aspects of the car. For example a front engine rear wheel drive vehicle with increased power and engine weight.

Areas possibly affected by change include:

If the gearbox is transmitting a greater power, the oil will rise to a greater temperature than designed. With automatic transmissions the torque converter will be overloaded and may boil the fluid.

With decreased lubrication bearings have a chance of failing either by complete failure or seizure. Should bearings fail, multiple gears may engage, locking the gears and stopping either the engine or wheels or both.

If the engine stops, power steering and power assisted braking is lost.

If output shaft locks, differential will allow wheels to rotate backwards and forwards, slipping, generally ensuring the car will be uncontrollable and cause yaw instability (spin).

If the weight over either set of wheels increases, so too does the ability of the brakes to apply torque and lateral forces to the suspension system via tyre friction.

In impacts (bumpy road for instance), impact forces will be higher on the suspension.

A combination of greater impact force and greater lateral and longitudinal tyre loading may enough to cause complete failure or rapid wear leading to failure.

The increased weight may cause the static ride height of the vehicle to change beyond ground clearance limits.

With a vehicle of greater power, the increased vehicle speed or decreased duration between braking may cause the brake system to overheat and become ineffective through either boiling of fluid, glazing, or pad gas emission.

With increased weight, the vehicle will have a greater energy at a particular speed, increasing the heat of the braking systems for a given braking rate. Again this may be unsustainable and lead to brake fade.

A combination of the two effects will bring about a far greater likelihood the brake system will be ineffective.

With increased weight in the front of the car, the front wheels are less likely to lock, making the rear wheels more likely to lock. Generally a vehicle should be designed never to lock the rear wheels. While locking front wheels eliminates steering ability, the locking of rear wheels ensures the vehicle will be unstable and want to spin.

Manifold intake vacuum may be less than or greater than designed for in the brake system, making the brake system less effective or more effective than intended. It is possible the brake system could become self energising under extreme circumstances.

With increased speed and weight the tyres of the vehicle may need to be upgraded to tyres capable of supporting a greater load at the greater top speed of the vehicle (irrespective of speed limits). The increased weight and speed will cause a heat build-up as the tyre flexes over the road as it rolls. Greater weight ensures more flexure, greater speed ensures flex happens more often at a greater flex rate. The combined effects may cause catastrophic tyre failure at high speed.

The available tyres may be limited in range, and may also be of an inflated diameter that causes an excessive change in speedometer and odometer reading.

The vehicle will require heating and cooling systems to be active to ensure retained ability to demist windscreen.

The installed engine will likely require a larger radiator to reject extra heat as emitted by the engine. However fitting an excessively large radiator will ensure the engine never reaches optimal temperature and will wear more quickly.

Engine installation may require modifications to the chassis to ensure the engine and all ancillary equipment is housed appropriately. The addition of the different equipment will change the frontal crash characteristics, firstly because the differently shaped engine will crush the firewall differently and behave differently as it does so, and also because the increased weight will increase the impact energy of the crash.

The modification of engine mounts may affect how the front structure behaves in a crash, possibly reducing the effectiveness of the structures in absorbing energy.

The chassis changes may inadvertently affect airbag sensors, possibly causing the airbag to release too early, too late, not at all, or under inappropriate circumstances.

The parts under the bonnet may be stiffer than the original parts, causing pedestrian safety impacts to increase in transmitted force.