Testing the new Paccar MX engine

The MX-13 is not new to the Australian trucking industry. More than 800 units of the Paccar engine have been in service in DAF-branded trucks since 2007, so it was only logical to explore new opportunities to use it within the Paccar family. The next brand to benefit from that strategy is Kenworth.

To date, the MX-13 has been powering a number of T403, T409 and T409SAR Kenworth trucks in testing, and some have been undergoing field trials with well-known fleets both in Australia and New Zealand. At the time of writing, the maximum travelled distance by any one of the test vehicles was just 150,000 kilometres, but we were assured of a much longer assessment before full production commences and the trucks become available for sale. 

“We are currently in the middle of the development program and no completion date has been set for a trial,” said Brad May, Paccar Australia Product Development Manager. “It will be launched when the program is finished. It’s not about the testing of the engines; it’s more about testing and refining the installation.”

The vehicles available to be driven at the Mount Cotton Training Centre included both manual and automated manual transmission (AMT) equipped Kenworth T403 and T409 (including a T409SAR) models in single and B-double configuration. To provide some comparison on the day, two DAF trucks with the same engines were present – a CF85 rated at 460hp and a XF105 with 510hp.

Once in production, the MX-13 engines are intended to be available in the same two ratings as in the DAF models. The 460hp version of the engine develops its maximum power between 1,500 and 1,900rpm and its maximum torque of 1,700 ft/lbs (2,300Nm) between 1,000 and 1,410rpm.

The higher rated 510hp engine develops its maximum torque of 1,850 ft/lbs (2,500 Nm) and power across the same rev ranges as the 460hp. Both ratings of the engine provide quite wide and perfectly flat torque curves that should result in good fuel economy when combined with the appropriate driver behaviour.

The test trucks were loaded at 35-37 tonnes GCM for the single trailers and 55-57 tonnes GCM for the B-doubles. Certainly not at their maximum capacity, but sufficient to provide a realistic impression of how the vehicles would perform in real world situations.

One aspect that stood out when driving the AMT-equipped trucks was how well sorted the interaction between the MX-13 engine and the Eaton AutoShift Plus transmission seemed from a driving perspective. Considering that AMT versions of the DAF MX-13 trucks have had many years of development with the ZF AStronic 16 speed transmission, the Kenworth/MX-13/Eaton 18-speed responded remarkably well with smooth and fast shifts in both directions and the off-the-mark clutch take up and initial shifting was particularly smooth.

The two AMT equipped trucks at Mount Cotton were the only ones manufactured so far and at the time were yet to be made available for testing by fleets. Both featured overdrive top gear in deference to achieving maximum fuel economy.

Read the full report and a behind the scenes story on the development of the new engine in the current edition of Prime Mover magazine, out now!

 

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