As is the case in the US, only Caterpillar and Detroit Diesel engines are fitted into the CST chassis, so far. Daimler is not ruling out a Cummins option but it would have to be an Australian development and not derived from a US design.
The integrated cooling package is all-new with Freightliner and Sterling using a unit including radiator, fan and all ancillary cooling equipment in one piece. This is fitted into position between the splayed front chassis members with the engine mounted behind.
By creating a single unit it is possible to mount the fan much closer to the 1,625-square-inch radiator, as there is no movement between the two, and this improves cooling capacity. The extra capacity is vital as the new technologies employed to reduce exhaust emissions provoke increased heat rejection in the new engines. Both Caterpillar’s ACERT C13 and Detroit Diesel’s Series 60 EGR put out considerably more heat and have forced all manufacturers using them to improve engine cooling.
A new fan clutch as part of the system is reckoned to improve cooling capacity and improve fuel use. The two-speed clutch idles open all the time at 500rpm, keeping coolant cooler and also keeping up with airconditioner’s coolant needs.
This reduces cycle time as the fan doesn’t engage as often. When it does engage it is starting from 500rpm meaning there is less belt snap as it softens the engagement. This should also have the effect of increasing lining life in the clutch.
The truck as tested was the CST on a 5400mm wheelbase fitted with a 525hp 14-litre Detroit Diesel Series 60, manual Eaton 18-speed box, with 1,512 litres of diesel tank and hauling a single trailer from Melbourne to Sydney along the Hume Highway. This particular model is specified for Whiteline Transport in Adelaide and will be expected to haul doubles back and forth across the Nullarbor as part of its task when put to work. As a result, the CST is fitted with 1:4.3 Meritor 50/160 rear axles whereas an operator actually running the Hume with this combination would normally choose taller diffs to do the job.
Out on the road the truck has a familiar look and from behind the wheel it seems little has changed. The roomy 48-inch sleeper cab with a mid height roof is not the biggest on offer in the CST range but has space for most drivers’ needs. A good size bunk and sufficient storage in the bunk area does the job. Overhead there is a shelf running the width of the truck providing another useful amount of storage but objects stored overhead are difficult to access from the driver’s seat when the truck is on the move.
In fact, there is a lack of useable storage accessible while on the road. The top of the dash slopes towards the front and there is only one small triangular space for odds and ends. The door pockets are useful but smaller than the better pockets on the passenger door, a result of this cabin being designed for the US and the left hand drive market. The drinks holders also leave something to be desired; they look great but a couple of bumps in theroad and a bottle of water will end up on the floor. A coffee cup may jam in tight but, in practice, drivers probably have to customise the holders to make them practicable.
The driving position is good with plenty of visibility. The bonnet is only marginally visible meaning very little gets lost to sight in front of the truck. If anything, the only possible improvement might be a small low window in the passenger door to get a better view of the nearside of the prime mover. The aerodynamic mirrors work well and are easily adjusted.
Overhead a triangular binnacle is centrally mounted and proves to be an ideal place to mount the UHF and FM two-ways. Below them but mounted at the same angle is the wraparound dash bringing all of the controls and instruments to hand for the driver. A clock at the top of the window divider in the middle of the windscreen adds a retro touch to a modern cab.
The Ezyrider seat is comfortable, like an armchair with a complex suspension system below and behind. There is a small amount of rocking within the seat’s suspension system out on the highway. However, the left hand armrest cannot be used as it restricts access to the Roadranger gear-stick. It would be useful when Autoshift is specified as Freightliner fit their own paddle control to the steering column.
Smooth acceleration
Getting out of Melbourne, going from traffic light to traffic light on Springvale Road tests the combination of Detroit Series 60 and Roadranger box.
Exhaust Gas Recirculation (EGR) has changed the nature of the engine and it takes some time to get used to the way the revs respond to the accelerator and timing the changes. EGR does tend to smooth out acceleration and the edge has been taken off what used to be a sharp rise. Shifting is still fast and accurate but the timing is slightly changed.
The noise from the Detroit is very noticeable during acceleration and deceleration in Melbourne’s traffic. Performance is good when the Detroit is working hard and digging into the well of torque available, but it is a noisy engine, especially when compared to the new smoother and quieter Cats and Cummins in their ADR 80/02 guise.
There is a certain amount of drive-train noise as the 2,500Nm (1,850ft lb) of torque works its way through the system.
However, when cruise speed is attained and the work is done it all goes quiet inside the cabin.
There is no denying this is a loud truck and it still has the loudest engine brake on the market. The radio has to be turned up to overcome the increased noise in traffic, but the truck passes the ADR 83 drive-by noise rules introduced this year.
Some Detroit owners may well be at risk of getting caught by the noise cameras being used in NSW if they modify the exhaust pipes.
This engine is unique in the Detroit scheme of things. This is the Series 60 engineered to meet the much stricter US EPA 07 rules now applying in North America but adapted to meet ADR 80/02 exhaust rules. Engines now being sold in Australia are those going down the main production line at Detroit Diesel’s main plant in Deerborn, Michigan and not from a special build facility as they have been in the past.
The 1,850ft lb torque rating is only available here in Australia as the local Freightliner and Sterling organisation deemed it essential to compete in the market. Similarly, when these engines are developed for North America the test cycle used includes 1,500 hours on the test bench but when testing for Australian conditions they are run for 2,500 hours.
This will be the last incarnation of a Series 60 we will see in Australia as it is due to be superseded and become part of history with the introduction of the HDEP in the next few years. The Heavy Duty Engine Platform (HDEP) is the Daimler Group’s first world engine and the same basic engine architecture, an inline six-cylinder diesel engine using EGR, SCR and turbo-compounding will be used in all of the global giant’s brands, Mercedes-Benz, Freightliner, Sterling, Western Star and Mitsubishi Fuso.
As the last of its kind this engine will be well remembered as the first electronic engine and one of the trailblazers of the ’90s. It is now the next century and the 12.7 and 14-litre versions of one of Australia’s favourite engines will join the two-stroke Detroits of the past as part of the company’s rich heritage.
Wind drag minimised
Out on the Hume Highway this engine and the CST, riding on front taper-leaf springs and the Airliner four-bag suspension on the rear, are most at home. This model cruises at 100km/h running at 1,700rpm and the cab is quiet with very little wind noise making its way into the cab. The full-sized wind tunnel Freightliner has built beside the Swan River at its Portland, Oregon HQ has been put to good use, fine-tuning design to minimise wind drag and, consequently, wind noise.
The latest model available from Freightliner in the US, Cascadia, was developed in the wind tunnel and is said to be ‘slippery’ in the wind and a major improvement on the current Century.
With the cruise control set at 103km/h the truck motors on. However, when there is some overrun the engine brake kicks in at 105km/h reducing speed immediately and, as a result, the engine brake cuts out, then the truck speeds up and the jake is back on. The system should be set to bring the speed back down below 103 before it speeds up. This would avoid a continuous one or two-second engine brake application every few seconds on a downhill stretch of road.
Even when the truck is climbing it is possible to take full gears all of the way, only using the splits in the top one or two gears. Going up Aeroplane, heading north on the Hume, the semi makes it over the top with the Detroit at 1,400rpm and road speed around 55km/h. Flexible engine response for fast gear changing is good and it is easy to get into the rhythm of fast changes when accustomed to this engine. Most of the time down changes bring revs right into the middle of the maximum torque band.
At the end of a full driving shift from Melbourne to Sydney the strengths of this model are apparent. It is a very competent open highway runner capable of holding its own with enough power and torque to do the job and the comfort levels are good enough to reduce fatigue on long shifts.
The truck’s disadvantage, its high levels of engine noise inside the cab, is less apparent at 100km/h where it will spend most of its working life.