The mission Prime Mover chose to accept was to determine whether the renowned fuel efficiency of Scania’s six-pack powertrain can be harnessed with acceptable performance hauling a B-double with a gross combination mass (GCM) north of 60 tonnes on an undulating route east of Melbourne.
Considering most current multi-trailer prime movers sport 550 or 600hp ratings, ‘Is 500hp enough?’ seems a fair question to ask. Perhaps more to the point, ‘Is there a place in the Australian full-weight B-double (or dare we also mention A-double) market segment for 500hp prime movers?
Of course, many variable factors must be taken into account, including average GCM and the extent of undulations on the route most travelled.
It’s surprising, for example, how much difference a 55 tonne GCM compared with a 62.5 tonne GCM makes to the average speed of a combination on a long and steep climb.
Interestingly though, making a decision on the horsepower rating alone could prove erroneous due to the fact that the torque rating often plays a more important role than outright horsepower in determining the suitability of a truck for a given role.
To put things in perspective, a popular engine rating for linehaul B-doubles is 550hp and 1,850lbft (2,508Nm) of torque. In comparison, Scania’s G and R 500 variants deliver 500hp and 1,881lbft (2,550Nm) of torque.
So, while at first glance the 550hp rating might sound more impressive, it is the torque produced in the lower reaches of the RPM band that actually hauls the truck up the hill more so than the horsepower.
Therefore, all things being equal, with its extra 31lbft (42Nm) of torque delivered between the exceptionally low 1,000 and 1,350rpm, the 500hp Scanias could potentially outclass 550hp opponents on a climb.
But as the old adage regarding human behaviour notes, perception is often interpreted as reality meaning many will continue to believe that higher horsepower equals better performance.
It can be a similar story in the sensory realm whereby a vehicle that makes more noise can be easily perceived to have better performance than a quieter one.
This is a factor that has traditionally worked against European trucks in the Australian market, particularly when compared with those originating from another part of the northern hemisphere where twin seven-inch chrome stacks were at one stage the signature feature of all-powerful prime movers.
But time inevitably moves on and nowadays the quest to extract every ounce of bang from each precious litre of fuel, not to mention considerably lower emissions, has more or less overtaken the glitz and glam factor in terms of being the number one priority of most successful commercial haulage operations.
With this in mind, Prime Mover settled into the premium black velour upholstered driver’s chair of an R 500 hitched to a curtain-side B-double set that according to a certified weighbridge docket was grossing precisely 60.7 tonnes.
The docket also revealed ideal weight distribution with 6.4 tonnes on the steer, 16.3 tonnes on the drive and respective tri figures of 18.84 and 19.16 tonnes.
This shows that the R 500 with its 3,825mm wheelbase is ideally suited to multi-combination applications.
Having started out from Scania’s Laverton branch, ahead lay a 379km round trip taking in the picturesque hills and dales of eastern Victoria from the Melbourne metro to Leongatha via Caldermeade.
Importantly, every operational detail of the drive would be recorded by the inbuilt Scania Communicator C 300 telematics unit, providing an accurate fuel consumption figure and other vital data at the end of the journey.
Moving off, it was impossible not to be impressed by the whisper quiet environment and ultra-refined yet well controlled ride thanks to the four-point air-suspended cab.
The leather-bound steering wheel complete with a flat section at the bottom adds to the high-end European feel, somewhat belying the reality that we were, in fact, driving a heavy vehicle.
Indeed, it’s hard to adequately describe in words the extent to which such a pleasant driver’s operating environment tends to mitigate the stress when guiding a 60-plus tonne multi-combination vehicle through hectic traffic situations.
This notion was put to good test while surrounded by Melbourne’s morning peak mayhem, with the Scania’s sophisticated 14-speed Opticruise automated manual transmission – featuring a direct (1:1) top ratio – holding eighth gear at a steady 40km/h with 1,400rpm registering on the tacho during the climb up the Westgate Bridge.
Once over the crest the R 3500 retarder and engine brake combo came to the fore, checking speed to 60km/h with no brake pedal intervention.
Despite the fact that from here to the Burnley Tunnel it was stop and start all the way, the powerful yet relaxed nature of all aspects of the Scania’s operation instilled a similar calmness into its driver.
For instance, features like Eco-roll – which engages neutral to save fuel on the overrun – can be fully taken advantage of in heavy traffic if the driver accurately anticipates the ebb and flow rhythm of the traffic and backs off the throttle as early as possible.
Flowing the vehicle along in this manner virtually negates the need for the service brakes except for the final few metres before a stop.
Other standard active safety features such as lane departure warning (LDW), electronic stability control (ESC) and autonomous emergency braking (AEB) provide added peace-of-mind for the driver should an unforeseen circumstance arise.
Upon entering the Burnley Tunnel, the powerful retarder reiterated its worth keeping velocity at 75km/h in 10th gear at 1,300rpm during the long descent.
The subsequent climb at the other end saw the Scania hold 35km/h in seventh gear at 1,400rpm.
As the trip unfolded through the vista of stunning scenery, it became clear that 1,400rpm was indeed the ‘sweet spot’ with this engine, not only when pulling hard up hills but also cruising quietly and effortlessly at 100km/h, thanks to a tall 3.42:1 final drive ratio.
The lengthiest and steepest climb was in the mountainous Caldermeade district where a particularly sharp pinch caused the Scania to briefly drop into sixth gear, once again holding 1,400rpm and 25km/h until the grade levelled slightly, allowing it to grab seventh gear and claw its way back to 35km/h before the summit was reached.
There were a couple of instances on the steepest sections where manual was selected to prevent an unwarranted upshift, but for the most part the Opticruise transmission gauged the conditions and selected the appropriate gear with impeccable precision.
Another notable climb on the M420 heading back towards Melbourne near the Stud Road interchange saw the Scania hold steady at 70km/h in 11th gear at 1,200rpm.
On the all-important topic of fuel consumption, during the outbound journey with relatively level running the dash display climbed steadily to peak at 2.0km/litre (5.65mpg) before receding somewhat as the mountainous regions took their toll.
Still, the trip average of 1.87km/litre (5.28mpg), as recorded by the Communicator, was a commendable result given the demanding conditions of high GCM, heavy traffic and lots of climbing.
Even more astonishing was the revelation that 20 per cent of the 379km trip – equating to 75.8km – had been completed in Eco-roll mode with the transmission neutralised, engine idling and using minimal fuel.
Among other revelations, it reinforces the need for all drivers to be clued up on eco-driving techniques in order to exploit the full potential of Eco-roll and other fuel saving features incorporated into modern trucks.
Put simply, being ignorant of such features is a sure path to higher fuel bills.
Many fleets are also realising the benefit of providing financial incentives to their drivers if specific fuel consumption targets are met.
These measures are the keys to maximising fuel efficiency and minimising whole-of-life costs for the operator.
In the final wrap-up, the Scania R 500 passed with flying colours as a worthy contender for multi-combination roles with GCMs of up to 62.5 tonnes.
Its attributes of sufficient performance, outstanding fuel consumption and supreme driver comfort and convenience add up to a package par excellence in the heavy-duty Australian truck market.