Scania R 480 put to the test

Choosing a prime mover is all about getting the right specification to suit the task, making sure the truck is up to the job. Prime Mover looks at the Scania R 480 to see if it can cut the mustard.

Test-driving the Scania R 480 hauling a B-double on the road from Adelaide to Melbourne brings to mind a number of choices the average truck buyer has to make and also brings into question some of our well-held beliefs. This new R 480 is not a major new design, but more a pragmatic answer to practical problems faced by both truck operators and manufacturers.

Prime Mover spent the day on the Western Highway with Scania seeing how well their new 480hp, 13L engine performs in the role of a B-double prime mover. It was also an opportunity to assess whether the preference for 550hp plus on B-double work is necessarily the way to go in all circumstances.

The first two hours of the journey from Adelaide to Melbourne provide a useful opportunity to assess just how big a deal horsepower is. Trying to get through the morning traffic, crossing the city from the north-west to the south-east to meet up with the highway heading east for Melbourne, is typical city driving for a B-double. The route is a series of major roads across the city, featuring more than its fair share of traffic lights and well populated with general city traffic going about its business.

The stop start progress down Portrush Road from traffic light to traffic light can be hard in a fully loaded B-double. After taking off at the green light, the driver will work hard to get the truck up to 60 km/h just before another red light appears and the whole thing has to be brought to a halt again. With a manual constant mesh gearbox this can be hard work, going up and down through the gearbox, constantly looking for an opportunity to accelerate and making sure the rpm levels are just right for smooth changing.

The combination of the Opticruise AMT gearbox and the transmission retarder on the R480 mean the effort involved in going up and down through the box involves stepping on the accelerator when the light is green and pulling the retarder control on the steering column stalk when the lights are red.

A high horsepower prime mover can get away from the lights a little quicker with its higher torque rating. However, in practice, in the flowing traffic trying to get across Adelaide, the prime movers trying to do the same job as the test vehicle with higher power engines don't appear to gain much advantage. The stop/start nature of the route keeps most of the trucks travelling around the same pace, even though it may take the lower powered prime mover a little longer to make it to the next red light.

The next test of the B-double is the climb out of Adelaide on the road to Melbourne. This is a steady, unremitting grade, which is simply a test of truck torque. There is no opportunity to take a run up as the junction turning onto the main road is right at the foot of the climb. Trucks slowly round the junction onto the main highway and have to get stuck into the grade straight away.

Despite being a 480hp engine, the Scania 12.7L engine still has 2400Nm of torque, this equates to 1770 ft lb in the old money. At this level, the Scania engine is not far off the 1850 ft lb regarded as the industry standard torque level for this kind of truck. But this slightly lower torque level does mean the truck takes longer to work its way up through the gearbox from the virtual standing start at the foot of the grade. At least its efforts are maximised by the very smooth changing AMT, the Opticruise.

In terms of trip time, this truck will lose ground when climbing a steep pull like the South Eastern Freeway up and over the Adelaide Hills. It is a long and difficult grade and a truck needs every bit of torque it can get hold of to make the best of this climb. Over the length of the entire day's drive, however, the difference would be quite small in the overall scheme of things.

Most of the route across South Australia and into Victoria is relatively easy-going and the 480hp ,13 LScania engine is not at much of a disadvantage at all. The combination of relatively high engine torque and a responsive quick changing gearbox means it is possible to maintain momentum at a similar level to that achieved by more powerful trucks with less responsive gearboxes. Probably one of the causes of differing trip times is more likely to be different speed limiter settings, with Scania setting the limit at exactly 100 km/h while many others on the road are set at 103.

From the driver's seat it is possible to tell this truck is not a 550 hp model but these kinds of judgement are very subjective. If there was a 525 hp sticker on the truck door, any driver handling this truck would not be surprised. Many of the little signs we drivers see as indicators of a good power output are often the result of a high torque output. Keep the torque levels high and most drivers will regard the truck as a good performing vehicle.

Another subjective opinion comes from feeling about how the truck drives. The feedback from the vehicle and the way it responds to pressure on the accelerator, unevenness in the road or steering inputs will vary widely from driver to driver. There is however an almost quantifiable difference between the real driver gets from a purely SCR emission controlled engine when compared to its EGR alternative.

Quite often, this difference is hard to perceive. Rarely is it possible to compare two trucks side-by-side doing the same job and from the same manufacturer. Many EGR engines have plenty of horsepower in reserve and can perform very strongly both in terms of power and torque. However, this 480hp engine in the Scania does not have plenty of power in reserve. It has to work hard quite a lot of the time, but there is still an impression it is doing it easy. This is quite common among trucks and which do not use EGR but just SCR.

For Scania truck buyers there will be a choice as the company are still offering their EGR engines at Euro 5 alongside the newer SCR models. The EGR engines are an older design but use a more sophisticated fuel injection system, the XPI, also used by Cummins. The engine block for the SCR engines is part of the new family of engine designs, which include the 730hp V8, fitted to the top of the Scania range.

In the sort of application in which this vehicle is being tested, as B-double prime mover, the EGR version of the engine may have an advantage, as it is available with an extra 100 Nm of torque, 2500 as compared to the 2400 on the SCR version. This brings the torque output even closer to the industry standard of 1850 ft lb at 1844. This gives potential Scania truck owners a choice between an EGR engine with a little more torque to get the job done and the more free running SCR version which is likely to be more economical in terms of fuel.

The smooth running SCR is another component adding to the feeling of a relaxed drive when handling a Scania like this. The combination of low noise levels in the cabin and a well-balanced truck and cabin suspension means even on some poorly maintained roads with the engine working hard, the sensation for the driver is relatively smooth and quiet. Also, the ease of use of the truck went out on the open highway is also quite relaxing. The Opticruise gearbox has been set up well enough to be responsive to changes in road conditions or driver inputs in just about every situation.

Ergonomically, the cabin is also set up quite well. Once travelling at highway speed, it is possible to control most of the vehicle systems that need driver intervention from the buttons in the middle of the steering wheel. These are for the cruise control and automatic retarder control, which can set a maximum downhill speed, bringing in the retarder as and when required to maintain a safe descending speed.

The relatively quiet and relaxed atmosphere within the truck's cabin does allow the driver to concentrate on what is going on outside the vehicle. It's possible to monitor the road conditions and traffic around the truck to make the journey as safe as possible. There are no distractions within the cabin and the driver does not need to get involved in changing gears or engaging the engine and service brakes, the system can handle it by itself, if required.

This is another debate within the industry. There are some who contend the driver needs activity within the cabin to keep them awake and active. The argument goes, the driver will become drowsy if the cabin is too quiet and they don't have anything to do except point the truck in the correct direction down the road. This kind of debate will go on and on, but this driver knows they feel less fatigued after five hours in a truck with automatic and automated systems than they do after five hours in one without any automation.

A number of questions have been raised by this test drive and the debates on them will continue well into the future. This Scania R 480, using the 13L SCR engine from the Scandinavian truck maker, does give the truck buyer a choice if they come down on one side of the argument or the other.

In the debate about how much horsepower is required for a B-double, there are many answers; but a 480hp engine can fit the bill for some operators. If they want something with a bit more clout, than Scania will offer them the V8 power plant at over 500 hp. If they are more comfortable with an EGR engine and worry about additives, Scania have one of them too. If the driver feels they need distractions within the cabin to keep their mind active, they don't need to turn any of the automatic systems on.

However, this Scania R 480 does have some of the answers. It is smooth running and there is enough power and torque to get the job done, even if it may take a little longer than some other trucks. It is a very comfortable and easy truck to drive, and the design makes for a relatively restful drive out on a stressful highway. Overall, it offers a clear choice for those who come down on one side or the other of the many debates within the trucking industry.

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