Hushpak muffler improves maintenance and passes noise test


Working collaboratively with a mine service provider, Hushpak set out to:

  1. Eliminate maintenance accessibility issues
  2. Ensure compliance with the in service noise specification of 123 dB
  3. Achieve the above at a fraction of the cost of traditional attenuation

Traditional “one-type-fits-all” attenuation solutions on haul trucks can cost up to $200K and add 4 Tonne of extra equipment to the machine.

This causes accessibility issues and maintenance challenges that ultimately impact on vehicle performance and payload. Plus, the machine may still not pass the noise test on the first attempt, requiring makeshift trial and error adjustments. Visual obstruction and confined space within the engine bay make it tough for maintenance staff to keep the engine bay clean and free from oil. As a result, the vehicle has high potential to overheat and there is increased risk of fire.


Having noise tested hundreds of mobile machines, Hushpak has proven knowledge of acoustics and predominant noise sources. Our specifically engineered solutions are developed using sophisticated analytics and design tools to achieve exceptional results with less capital outlay.

For a CAT 793D haul truck, which can exceed 125 dB – the engine exhaust was the main noise source. Hushpak replaced the muffler with a custom designed muffler, specifically developed to treat the problem frequencies associated with the CAT 3516B HD engine.


Eliminate maintenance accessibility issues
Installation of guard rails and cover over muffler improved safety and ease of access during maintenance. Less than 450 kg was added to the vehicle – increasing payload and reducing wear and tear.

Achieve less than 123dB at low capital cost
Installation of Hushpak’s custom designed muffler package achieved the target noise level immediately – without adjustment – allowing the 793D to operate in the shortest possible time. Noise test results were 122 dB – under the in service noise limit.

More info

For more information on this case study, or to enquire about a similar project please contact:

Michael Neville | General Manager – Hushpak Engineering
+61 2 4964 4000