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Tips for Test Driving: Before you drive Pt I

words - Joe Kenwright
You might think you're ready to test drive a prospective purchase... But have you done your research?

There was a time when a test drive could tell you everything you needed to know about whether a vehicle was right for you. Now, as safety and fuel economy assume a greater level of importance in most purchase, there are some aspects that need to be researched before you even embark on a test drive.

There are several authorities whose test results are easily accessed on the internet that can tell you what to expect from a certain make and model in a crash.  Sources of the same information in print format include government road safety and transport authorities and motoring organisations.

Australian Design Rules
Australian Design Rules that dictate minimum standards of vehicle safety in all vehicles registered on Australian roads for almost 40 years have tightened-up dramatically since the 1990s. There are websites with information about important new safety standards applied to vehicles sold in Australia along with the number of the ADR that covers each new requirement.

The presence of the correct compliance plate is critical confirmation that the vehicle meets these standards. Even with imports that were brought into Australia secondhand, the absence of such a compliance plate should still be a concern if it is not accompanied by a comprehensive engineer's report verifying that it meets minimum Australian standards that apply to a vehicle of that age.

Australian NCAP
The next level of safety assessment for new vehicles is the Australian New Car Assessment Program (more here). This stand-alone body employs crash test procedures which are closely aligned with the European NCAP process (more here). 

The crash tests are controlled laboratory tests that assess various aspects of driver, passenger and pedestrian safety of popular vehicles. Because they are based on set test situations, the NACP test programs have their critics who argue that a good NCAP result can generate compromises in other areas.

Although there are strong arguments for another level of research based on real world crashes, NCAP has revealed some poor crash performers. When local and overseas results can be easily accessed on the internet, you can usually research low volume models not tested in Australia.

Real World Crash Studies
Australian road authorities with the support of motoring organisations have contributed to several national studies based on real world crashes via collating data on the severity of injuries generated by vehicles already on the road.

While the methodology has its limitations, it does generate a useful third tier of information especially for older vehicles not covered under the latest Australian Design Rules or too old to have been tested under NCAP procedures. In combination with NCAP results for more recent models, it can produce a more complete picture of how your choice of vehicle stacks up.

Modern cars list safety equipment using acronyms. It helps to know what some of the more common descriptors stand for:

ABS -- Anti-lock Braking System: An antilock braking system properly calibrated for Australian roads is the single most important safety development of recent years that can help avoid a crash.

When most drivers tend to lock up the brakes in a panic situation and slide into what they are trying to avoid, ABS maximises grip and control during full braking.
It not only shortens braking distances dramatically, but preserves steering under maximum braking effort for evasive action.

If it's working properly, it can generate noisy and violent pulsing through the brake pedal and throughout the car to the point where it can sound like there is a mechanical fault but that is how it is meant to be.

EBA -- Emergency Brake Assist: (sometimes known as Electronic Brake Assist) was invented after it was discovered that drivers don't always apply enough braking force to make ABS work effectively in an emergency situation. It uses extra wizardry in the ABS system to sense if emergency braking is required then takes over and automatically applies extra brake force until the driver lifts his or her foot from the brake pedal.

EBD -- Electronic Brake Force Distribution: This can be an important partner to ABS and EBA as it can increase or reduce the brake force to each wheel according to load, grip, steering and weight distribution.

ESP or ESC or DSC (or others) -- Electronic Stability Program: (the original Daimler Group brand name, or Electronic Stability Control): Increasingly referred to via its generic description, stability control, this system is generally seen as the next 'magic bullet' in terms of crash avoidance and road safety.

Under local laws stability control will likely be mandatory on all new cars by 2011.

Stability control uses a powerful electronic control unit to apply and release the brakes on each wheel as well as vary engine power in the required sequence to bring a vehicle back under control during a skid or slide. 

Although stability control is uncanny in what it can achieve, it is ultimately limited by the laws of physics in terms of tyre grip and speed. The system is also only as good as its calibration -- something that requires special consideration in Australia's varying road conditions. Changing wheel, tyre or brake specifications can upset its effectiveness.

SRS Airbags -- Supplementary Restraint System airbags: The letters SRS are the critical difference between Australian airbags and other systems elsewhere (such as those used in the USA).

In the USA, airbags are often bigger and calibrated to react earlier and more violently in the absence of compulsory seat belt wearing hence reports of horrific injuries to young children. In Australia, airbags are part of a multi-level system built around compulsory seat belt wearing and are triggered to respond later and less violently during more severe collisions when the seat belts are not enough.

Important components of the Australian system include head restraints to minimise whiplash when impact against the seatbelt forces an occupant back into the seat and seat-belt pre-tensioners (usually triggered by a pyrotechnic device) which tighten the belt to compensate for any stretch in the webbing or loose belt-winding in the retractor reels.

Although airbag inflation can be less violent in Australian market vehicles, it is still explosive enough to cause injury if for example a front passenger insists on resting their feet on the dash. Dash mats and seat covers can also prevent airbags from working properly.

The rule of thumb is the more airbags the better, but airbags are of little use if the passenger cell structure in which they are mounted lacks crash integrity.

In the early days of ADR crash safety, the presence of an airbag was often a band-aid measure to cover shortfalls in a vehicle's crash structure. During this period, several cars with good crash safety came without airbags when they didn't need them to meet the standard.

Cross-referencing the various crash studies is just as important as counting airbags in this context.

TCS -- Traction Control System: traction control exploits the ABS system to stop the driven wheels from spinning under power. More sophisticated systems also reduce engine power until traction is restored.

Because the system can control each driven wheel individually, it can partly generate a limited slip differential effect as it will stop a normal differential from feeding all the drive into the wheel with less traction. Although it is a valuable safety feature, it is important that it can be switched-off for certain snow and slushy conditions.  

For green and financial reasons, there is added pressure now to reduce fuel usage. But chasing fuel savings alone can be short-sighted when some vehicle choices that appear to save fuel will force you to outlay more upfront and generate higher parts and servicing costs.

A good place to start is the comparative fuel figures supplied with all new cars and most of their predecessors over the last two decades. There is a tendency to combine today's city and highway figures into a single average figure -- however the latest fuel usage advisory decals must include city and highway measurements. Unless you travel in a perfect balance of city and highway running, this can deliver unrealistic expectations.

Pick the fuel figure that best describes most of your running and use that figure to make the comparison. Some vehicles that are extremely frugal on the highway can turn into gas guzzlers around town.

Compare these figures with independent tests. Today's manufacturer-supplied fuel figures are generated in a test laboratory and are more useful for comparisons than an absolute guide to what you will achieve.

Petrol Vehicles
Pre-1986 cars: Most pre-1986 cars require leaded petrol although some can run on unleaded (ULP) without damage. Check with the vehicle manufacturer if in doubt. Lead Replacement Petrol (LRP) has virtually disappeared as leaded vehicles have left the road so the purchase price will need to reflect this.

Some models (such as KC Laser/Mazda 323) launched late in 1985 met 1986 unleaded fuel requirements early and can be the cheapest way of getting into an unleaded car.

Wider availability of high octane 98 RON premium unleaded petrol (PULP) is good news for older high performance cars that required 98 RON high octane leaded fuel which is no longer available. Owners can keep these vehicles on the road using PULP and adding a lead replacement additive to the fuel. Alternatively, you can opt for engine modifications (installing harder valve seats) to suit PULP fuel.

Post-1986 cars: Most new cars sold after 1 February 1986 should run on ULP. Check the Compliance Plate for ADR 37 compliance and look for the narrow fuel filler neck.

However, many new vehicles built to 1985 standards or earlier were stockpiled after new car sales stalled in 1985 and were not registered until 1986 or even later. Their compliance plates should be dated prior to February 1, 1986 with ADR 27C compliance instead of ADR 37 and therefore may still require leaded petrol.

An increasing number of post-1986 vehicles require PULP (95 RON or higher) and will incur damage if run on basic ULP (91 RON) if they do not have a knock sensor. Check that PULP is readily available in your area if a particular model requires fuel of 95 RON or higher.

After Euro III emissions requirements were introduced in 2006, more vehicles require 95 RON or 98 RON PULP to deliver claimed power and economy figures. Some will no longer run satisfactorily on basic 91 RON ULP.

This latest shift to higher octane fuels in the latest models is not the concern it seems when the extra efficiency should more than compensate for the extra fuel cost.

Late model cars with fuel injection are more efficient and reliable than carburettor engines but injectors, fuel pumps, computers and other parts are more expensive if they fail.

LPG/Dual Fuel and LPG-only
LPG can reduce fuel costs providing LPG prices are much lower than petrol -- some engines can use up to 20 per cent more on LPG than petrol! Generally, the higher the fuel consumption and the greater the distances, the greater the saving.

Check that an LPG conversion has been carried out to the required standard as many home conversions are illegal -- and lethal. Gas tanks must be replaced by law within a specified time frame.

Most LPG conversions should run on petrol and gas. Even on gas, some draw on the petrol system under extreme loads and require the driver to switch to petrol on a regular basis. Owners who ignore these requirements generate expensive damage to fuel systems. Check that the engine will also run on petrol.

Engines not designed to run on LPG can suffer from cracked cylinder-heads and/or valve seat damage. 

Late-model Ford Falcons can be factory-optioned with LPG-only engines. These engines have been optimised for long life on LPG and represent the lowest LPG purchase risk followed closely by other factory-approved systems.

Diesels are improving, with much better fuel economy than petrol engines and performance that can now rival petrol cars.

Australia was locked out of the latest diesel technology until clean new diesel fuel was introduced in 2006. Most of the new technology diesels were not introduced until sometime later in 2006 to ensure that the new fuel had replaced all the older and much dirtier diesel fuel nationally. 

Older diesels can still be noisy and rather slow. Drive the car you are interested in to see if it suits you. Consider too that diesels do not operate efficiently until warmed-up and make little sense for short trips.

The buzz-words to look for in today's diesels include: turbo, direct-injection, common-rail, intercooler, variable-geometry. The more of these features a diesel engine has, the better it will perform, the more economical it will be and the lower the CO2 emissions.

Diesels can command a $2-3000 premium when new, some of which continues as a used vehicle. Diesels also require specialist servicing that can include more expensive oil and filters and they can generate high repair costs if turbochargers, injector pumps and injectors are damaged.

Do you cover enough distance to justify the extra outlay? Apart from diesel costing up to 15 cents per litre more, that $3000 extra outlay can pay for enough petrol to cover almost 22,000km (calculated at $1.40 per litre using 10L/100km). Most diesels won't recover their extra initial outlay in fuel savings until well past 50,000km.

It is important to note post-2006 generation diesels can be extremely intolerant of contaminants and will generate expensive repairs if they are fed dodgy fuel. A reliable supply of quality diesel fuel is essential. Earlier diesel technology is far more tolerant of fuel variations.

Although the powertrains in a hybrid are combined in different ways, the principle behind hybrids remains the same -- use a smaller and frugal petrol or diesel engine than normally required, then supplement it with an electric motor when extra performance is needed.

In some hybrids, the electric motor can take over completely in certain low-load situations. All rely on regular running on the diesel or petrol engine to keep the battery charged.

And here's the rub. If a hybrid is used infrequently or on short stop-start trips only, the battery will eventually discharge and leave you with an underpowered petrol or diesel vehicle that will now have to haul a dead battery pack and electric motor until it recharges.

Battery life is also not well documented with some manufacturers quoting up to $10,000 for a replacement. Because Toyota claims as of 2008 it has only replaced two batteries in Prius models first sold in Australia from 2001, battery life is still an unknown factor but when it does die, a new one could cost up to $10,000.

Hybrids can be brilliant and currently work best for Australians who combine stop-start city traffic with extended cruising. The next generation of dual-mode hybrids that will see larger cars using hybrid motors to boost efficiency in all conditions could change the effectiveness ratio to suit more open road work.

Also read Part II of our Test Driving Tips here

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Published : Friday, 1 February 2008

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