ProStar links International with IVECO for a renewed attack on the Australian market. Words by Brenton O’Connor – Images by Geoff Parrington.
It’s been a long wait between the announcement of the return of International to the Australian trucking scene and the arrival of trucks on dealer forecourts, but, with trucks now available, ProStar is now a happening thing in the heavy-truck market.
With Navistar (the parent company of International Trucks), having entered into an agreement with IVECO Trucks Australia to distribute the ProStar range through the already established IVECO Australian dealer network, the brand returns at a point where it still holds street credibility amongst previous owners.
Since revealing its homecoming at the Brisbane Truck Show in May 2017, this is the first opportunity PowerTorque has had to drive the ProStar on Australian roads. It’s always something of a privilege to drive a bran-new truck, and in this instance my transport for a few days was in the form of a ProStar day-cab, fitted with a beautifully polished Hercules aluminium body, coupled to a quad dog. The truck was loaded to its legal limit of 23,000 kg (without mass management) and the quad dog was loaded to 24,720 kg giving a total gross combination mass of 47,720 kg.
All ProStars are fitted with Cummins X15 engine, with a standard rating of 410 kW (550hp) and 2508 Nm (1850 lb-ft.) of torque. However, International Trucks Australia had re-programmed this particular truck to the engine’s maximum output of 600 hp and 2050 lb-ft of torque, and the power was truly impressive.
Standard gearbox on the ProStar is the Eaton 20918B 18-speed constant mesh transmission, but in this instance it featured the optional Eaton UltraShift PLUS automated manual technology. This combination also provided a unique opportunity to experience the benefits of the partnership Cummins and Eaton have forged by mating their engine and transmission to each other respectively, with ADEPT technology.
The ProStar is fitted with Hendrickson Primaax EX air rear suspension, with parabolic springs fitted to the steer. Brakes are drum all round; however, they are fitted with ABS and automatic traction control as standard. When the truck is fitted with the optional Eaton UltraShift transmission, a hill-start aid is also fitted.
Unlike Kenworth and Freightliner, International uses a steel cabin rather than aluminium. The cab is available in day cab (as tested), extended cab (with a 660 mm bunk) and also a full sleeper cabin with raised roof.
The day cab is particularly limited in length (112” bbc), and, as such, seat travel was limited for taller drivers such as myself, plus the engine firewall intrudes into the cabin competing for legroom and foot space. For taller drivers, the extended cabin provides further legroom, plus it includes additional storage options for personal items. These options are missing from the day cab configuration.
A nice touch include by International is to fit leather seats as standard, and the driver’s seat is a unusual brand called GRA-MAG, which is the American arm of European seat manufacturer Grammer. The seat has lumbar supports and plenty of other adjustments to help get comfortable.
As expected from such a sloping bonnet, visibility is excellent, rivalling even a cabover, as the bonnet drops away very quickly.
As such, it would be ideal entering construction sites as a tipper where space can be of a premium, the turning circle was also good thanks to the set-back front axle.
Noise levels from the Cummins X15 in-cab are as good, if not better than other American bonneted trucks using this engine; however, on engine brake application there is more noise, possibly due to the standard dual mounted stainless exhausts on each side of the cabin. Despite high ambient temperatures on the testing day, fan-on time was near non-existent, which demonstrates the radiator is getting plenty of air through the large grill, both saving fuel and noise from running the Horton two-speed fan.
Unusually for an American truck, the ProStar runs a CAN bus wiring system, which makes life easy for body builders to tap into the electrical power supply to fit safety systems. A typical example of this benefit being that if the door is opened without the park brake being applied the horn will sound. Furthermore, International fitted factory electric switches for the tipper body into the main dashboard, which, not only look smart, but also function well when compared with aftermarket switchgear being fitted by the body builder.
The standard-fit SONY single-DIN radio was difficult to use, and the speakers fitted were quite ordinary. It would be nice if International could fit a double-DIN radio system that incorporates GPS truck mapping into the truck as done by many of the Japanese and European truck manufacturers.
On the road, the ProStar is very easy to drive. With the maximum rating of the Cummins X15 and a gross weight of just less than 48 tonnes, the combination felt as if it was empty. For the test, a route from IVECO’s Dandenong headquarters through to Sale was selected and provided a good mix of city, freeway and country road surfaces as part of the evaluation.
The truck has excellent road feel, and sits on the road very easily on cruise at 100 km/h. Upon tipping the bonnet, there is a very complicated arrangement of universal joints from the cabin through to the steering box, which didn’t impede on road feel at all, but did feel slightly odd when manoeuvring through tight corners or around roundabouts.
The ProStar we tested truck was fitted with Meritor RT46-160GP rear axles, with a 4.11:1 rear axle ratio. Adrian Wright, chief engineer of International Trucks Australia, explained they would move to faster diff ratios than the typical 4.3:1 to provide better fuel economy. As such, the truck sat on 100 km/hr at just over 1500 rpm, which felt ideal for the combination. Also nice to see as standard fit, are the power divider and cross-locks on both rear axles.
The Cummins Eaton partnership is now outstanding, and the UltraShift combined with the X15 is the best I’ve driven from any American AMT. I did find that at lift off, and particularly when the truck was cold, the transmission was hesitant to upshift, and the truck would rev to near 2000 rpm before upshifting. To counter this behaviour I would manually intervene and upshift the truck earlier.
Out on the open road the gearbox is excellent, and makes very few bad-judgment shift errors. The advanced technology of SmartCoast, which selects neutral when there are no power or braking requirements on the engine when on cruise control, worked as well as any European. Once the truck had hit 3.0 km/h above the preselected cruise control speed, the gearbox would re-engage and apply the engine brake independently and without the driver’s involvement. Cruise control switches are operated from the steering wheel, and it would be nice to see International also fit the engine brake switches to the wheel for further ease of operation.
For the 388 km round trip, an overall average fuel consumption of 54.6 litres per 100 kilometres (1.83 km per litre) was achieved, which, given the truck was loaded at all times, was an impressive result.
There’s plenty to like about the ProStar, and with the impressive combination of Cummins X15 and Eaton’s UltraShift PLUS, driving is by no means a chore.