| ABS, ANTI-LOCK BRAKES
Anti-lock braking systems prevent skidding caused by too harsh a push
on the brake pedal. Cutting skidding not only makes for a shorter
braking distance, but also, very importantly, means the car can still
On gravel roads the braking distance might be increased by ABS,
however the system lets the driver steer the car. A few cars give
the driver the option of switching off the ABS if they think they
can outperform it in some circumstances. If driving one of these,
be sure you know the current status of the systems.
Safety belts must still be used even when airbags are fitted. Airbags
are intended to supplement safety belts, not to replace them. Which
is why they are technically called Supplementary Restraint Systems,
Airbags explode from the centre of the steering wheel and sometimes
also from the dashboard ahead of the front passenger when a crash
starts to occur.
Some cars now have side airbags which come out of the front door
trim or the sides of the seats themselves. A few even have air curtains
that fall down from the tops of the doors, offering side protection
to either the front seat occupants or to all occupants. Airbags
cushion some of the shock of the crash and reduce the chances of
them hitting unyielding parts of the car's interior.
The airbag remains inflated only very briefly. Apart from hearing
a very loud bang, the car's occupants may not be immediately aware
that it has been activated until they see the collapsed bag.
(See Four-wheel drive)
CENTRAL LOCKING, POWER LOCKING
All the doors are locked and unlocked at the same time, either by
a turn of a key or a remote control pad. In cheaper systems, only
the driver's door lock operated all the others while more expensive
systems have the central locking operating on both front doors,
or even from the boot lock as well.
An increasingly common feature is two-stage central locking. Turn
the key to the first position and only the driver's door is unlocked.
Turn it further and central locking operates on all the other locks.
This prevents an unwanted intruder from opening a passenger door.
At the summit of the central locking tree is the remote control
unit. Push a button at a distance of several metres and the car
is locked or unlocked, possibly with the car alarm being switched
on/off at the same time.
This is an advanced type of air conditioning where you set the desired
temperature and the climate control system maintains it, and the
humidity level, automatically. Usually only fitted to upmarket cars,
it's sometimes an extra-cost option on lower-priced vehicles.
Some climate-control systems offer the option of setting some
items yourself. Other systems insist on making all the decisions
for you. The drawback of the latter is that it frequently turns
the interior fan onto full for several minutes when the car is hot
after sitting in the sun and this can be distracting while driving.
Some car makers misleadingly call basic air conditioning 'climate
control' so check which you are buying.
Cruise control keeps the car at a predetermined speed without the
driver's foot on the accelerator. It should not be confused with
a hand throttle, fitted to some 4WDs.
Cruise helps you avoid getting booked for speeding when you inadvertently
creep up to an efficient speed instead of holding back to a speed
limit too slow for the conditions.
The car may lose speed when going up a steep hill, and it may
pick up speed on a steep downslope where engine braking isn't sufficient
to keep the speed down. Keep a close eye on the speedometer under
Most cruise controls let you increase and decrease the car's speed
manually with the hand controls.
When using cruise control, always keep your foot in the vicinity
of the brake pedal in case of emergencies. All cruise controls are
disconnected automatically if you touch the brake pedal and, on
a manual car, the clutch pedal.
CV (CONSTANT VELOCITY) JOINTS
CV joints are used at the front wheels of front-wheel-drive cars
to transfer engine power to the wheels, even while they are turned
to steer the car.
They are virtually troublefree in modern front-drive cars but
can cause real hassles in some older ones. They can be repaired
at moderate cost in most cars.
Diesel engines are more economical on fuel than petrol engines and
generally last longer between major overhauls.
On the downside, they are more expensive to buy, give less performance
and are noisier than petrol engines. Diesel fuel is oily to the
touch and it doesn't seem to matter how careful you are during refuelling,
you still end up with some on your hands.
Some of the latest-generation diesel cars are only a little noisier
than their petrol-engined siblings.
Most major service stations sell diesel fuel, especially in the
bush, but it is seldom discounted like petrol.
DOUBLE OVERHEAD CAMSHAFT
(DOHC) See Twin Cam
ELECTRONIC FUEL INJECTIONS (EFI)
Electronic fuel injection is more efficient than a carburettor in
controlling the flow of fuel into the engine. More power and lower
fuel consumption is the result.
Less maintenance is needed on an EFI system than on a carburettor,
but an overhaul is more expensive. However, many last for the lifetime
of the engine.
The simplest EFI system is single-point, sometimes called throttle-body.
It uses a single fuel injector. It is a low-cost system which lies
about midway in efficiency between a carburettor and a full fuel-injection
Much more common is multi-point fuel injection, which has an injector
at each cylinder. Multi-point injection can be sub-classified into
three types. In increasing order of efficiency, these are non-sequential,
semi-sequential and sequential.
Once only seen on expensive upmarket cars, EFI is used these days
on all but a few of the cheapest new cars. Some older cars have
a mechanical fuel-injection system, or a hybrid mechanical-electronic
one, but these can be troublesome as they get old.
FOUR-WHEEL DRIVE (4WD)
A car has greater grip on the road if driven by all four of its
wheels. This means safer motoring in slippery conditions such as
in wet weather or on dirt roads. It is particularly useful in icy
or snowy conditions.
Four-wheel-drive cars aren't intended to be taken off-road like
conventional truck-like 4WDs. Indeed, in an attempt to differentiate
4WD cars from 4WD trucks, some makers are trying to rename them
all-wheel drive (AWD).
Extra weight and friction due to the additional components reduce
performance and increases fuel consumption. Four-wheel-drive cars
are more expensive than two-wheel drive, everything else being equal.
The front wheels (not the rear) are driven by the engine. The engine
is normally mounted transversely across the car's body in a front-wheel-drive
car, though in some cars it's mounted fore and aft.
All things being equal, there will be more passenger space in
the cabin and a roomier boot because the engine is kept well forward
in the body.
There are no space-robbing components to take the power back to
the rear wheels and no differential under the boot.
Most big cars still have rear-wheel drive, which gives a car better
towing abilities. Because of the car's larger overall size, rear-wheel
drive causes fewer interior space disadvantages in big cars than
it does in smaller ones.
The vast majority of small and mid-size cars built since the early
1980s use a transverse engine/front-wheel-drive layout.
HANDLING AND ROADHOLDING
Roadholding means the ability of the car to grip the road. Handling
means the car's behaviour when it's being driven, not only how it
steers but also how it reacts to irregularities in the road surface
and even to the way it reacts to crosswinds or headwinds.
On a dry road in a modern car, you have to get going very hard
to experience loss of tyre grip and anything other than neutral
handling or mild understeer. So don't become overly concerned about
road testers' comments on handling in extreme conditions unless
you intend to drive the car fast and hard.
On the other hand, you should certainly have the driving ability
to get the car out of trouble should you encounter any problems.
An advanced driving school can help.
UNDERSTEER AND OVERSTEER
INDEPENDENT REAR SUSPENSION (IRS)
As the name suggests, the car's rear wheels are free to move up
and down independently of each other. This means the car is less
disturbed by uneven road surfaces, particularly on rough bush roads,
allowing a better ride and more precise roadholding.
(see UNLEADED PETROL)
Liquified Petroleum Gas, or LPG, is an alternate fuel which is almost
universally used in taxis in Australia but has never really hit
it off with private motorists outside of Victoria.
LPG cuts fuel bills by around 50 per cent. The cost of the gas
varies considerably from state to state, with Victoria generally
having the cheapest fuel. There is a marginal loss of performance
when using LPG, but in a good installation you will probably not
Boot space is often considerably reduced because of the bulk of
the gas tank and the fuel range is less. Converting a car to run
on LPG costs a little over $2000 and an existing conversion can
be transferred from one car to another for about $750.
Depending on fuel/conversion costs, it takes about 50,000 - 60,000km
to break even on the initial outlay.
Most twin-cam engines have a multi-valve cylinder head to increase
breathing and therefore combustion efficiency. Two inlet and two
exhaust valves are used for each cylinder.
Occasionally, a single overhead cam engine also has a multi-valve
layout, generally with three valves per cylinder, though some do
have four per cylinder. To add further complication, some older
twin-cam engines only have two valves per cylinder.
As a further complication, a few late-model car engines have five
valves per cylinder, three inlet and two exhaust.
Oversteer means the car tends to turn too tightly into a corner
- the tail slides to the outside of the bend. In extreme cases,
the car goes sideways and then backwards. This can lead to the car
hitting an obstacle sideways - where it has least strength and space
for occupant protection.
Oversteer isn't common in modern cars and there really isn't space
here to describe the intricacies of controlling it. If you have
a car which is a potential oversteerer, get yourself a book on driving
or contact an advanced driving school.
Understeer (see separate entry) is generally considered safer
for everyday drivers than is oversteer.
Power-assisted steering makes the steering lighter and cuts the
amount of steering wheel movement needed to turn the car through
a given angle. The car is easier to drive and park - especially
Power steering is very common in new cars these days, even on
small cars. This is due mainly to the extra steering effort that
is required because of the weight of the engine over the front wheels
due to front-wheel drive. It is also due to wider tyres now being
(see TWIN CAM)
SPLIT-FOLD REAR SEATS
All hatchbacks and station wagons, and an increasing number of sedans
use split-fold rear seats. Many cars now have what's called a 60/40
split, meaning that either a large part of the backrest can be folded
down, increasing the luggage capacity markedly and allowing one
passenger to be carried. Or, the narrow part is folded, increasing
the luggage capacity by a smaller amount and permitting two rear
passengers to be transported in the safety of seatbelts.
Some hatches now use the station wagon-style rear seat where the
rear seat base/s can be folded forward to further increase interior
Torque (not power) is the most important component in an engine's
output. We won't go into a detailed explanation but will simply
say that if your car will climb a hill with a fair load on board
and you don't have to change down gears too often, it has good torque
characteristics. When reading car makers' brochures and road test
report, look not only at the maximum figure for torque, but also
at the engine revolutions per minute (rpm). For example, a typical
two-litre engine might have torque of 180Nm at 3500rpm.
As a general rule, the lower the engine rpm, the better. Engine
designers are forever striving to increase the torque but not increase
the rpm at which the peak occurs. Naturally, there are always compromises,
but the engine in a family-oriented car should ideally develop its
maximum torque below 4000rpm.
Torque steer takes place when you accelerate hard in a front-wheel-drive
car. At some stage during the acceleration, a lugging may be felt
through the steering wheel and the car may try to pull to one side.
The effect is generally worse in a turbocharged car.
Torque steer only applies to front-wheel-drive cars and is much
more noticeable in powerful ones than in those with standard engines.
Good engineering can minimise torque steer. In many newer cars,
it has been virtually eliminated. Older Japanese cars generally
suffered more than cars from other countries, with the possible
exception of the Mini and older turbocharged Saabs.
Besides being aware that it happened, there is little you can
do about torque steer other than keep a correct grip on the steering
Traction control prevents a car's driving wheels from skidding under
acceleration by reducing power to the wheel, or wheels, which begin
A few advanced cars have traction-control systems that sense a
skid is starting to happen and try to correct it by a combination
of power reduction and braking specific wheels as necessary.
A turbocharger cannot work at full power the instant you push the
accelerator pedal. Instead, there is a lag of about half a second
to one second (it varies from car to car and according to driving
conditions) between the time you press the accelerator and the car
fully accelerating. When acceleration does come "on boost", it's
very strong and can take an inexperienced driver by surprise.
Turbo lag can be frustrating and is the main reason turbos have
lost favour in petrol-engined cars in recent years.
If you're driving a turbocharged petrol-engined car for the first
time, especially if the road is wet and slippery and the car has
front-wheel drive, be cautious with the Accelerator until you get
a feel for what the car is going to do.
Turbo-diesel engines are much more forgiving in their characteristics
than are turbo petrol engines. So also are the modern generation
of light-power turbo petrol engines. The downside of low-lag engines
is a lack of exciting power delivery.
TWIN CAM, DOUBLE OVERHEAD CAM, QUAD CAM
All these terms mean exactly the same thing: that there are two
camshafts above each cylinder bank. It offers a more efficient operation
of the engine's breathing, therefore more performance and lower
There can be some loss of drivability at lower engine speeds in
a twin-cam engine. This means it could be necessary to change down
a gear in some conditions when a single-cam engine could stay in
the higher gear. As a general rule, the more performance-oriented
the engine, the more gear changes will be necessary.
(See also MULTI-VALVE)
Petrol is unleaded in its normal state. Small quantities of lead
are added to increase its octane rating and therefore its combustion
efficiency. Unfortunately, the lead can cause damage to health,
particularly to young children living in urban areas.
Lead damages catalytic converters in unleaded petrol cars, greatly
reducing their emission-controlling ability. All new cars built
from February 1986 for sale in Australia must operate on unleaded
fuel. It is an offence to use leaded petrol in them. Many cars built
before then can operate satisfactorily on unleaded petrol.
Some cars need to run on premium unleaded petrol (PULP). This
is more expensive than standard ULP, is seldom discounted and isn't
available in all service stations.
Understeer means the car tends to turn less into the corner than
it should. In extreme cases, it won't turn into the corner at all;
it simply ploughs straight ahead.
For the average driver, understeer is easier to control than oversteer
and is generally built into a modern car's steering as a safety
It doesn't start to show up until you are driving hard and can
be reduced or negated by lifting your foot gently off the accelerator