New where it counts
On the truck front, GM has made serious revisions to the frame, suspension, engine and transmission so that, while I can’t tell you that it is “all new”, I can tell you it is new where it counts.
The 6.6-litre Duramax now uses Piezo injectors running at 2,000 bar or 30,000 psi to have better control of the injection moment and improve fuel economy. In addition, changes to the intake exhaust and block make the engine quieter, run better and improve performance. On the emissions side, these changes have reduced NOx emissions by 63% over last year.
Exhaust gas regeneration has been a contentious subject due to the frequency of regeneration and the detrimental effect it had on fuel economy. GM reports that the new system has improved by 75%, now running once every 1,100 km or so. DEF or Diesel Exhaust Fluid (a urea-based formulation) will now last about 8,000 km before needing to be topped up.
Changes to the frame have stiffened the front by about 25%, allowing any Sierra model to be equipped with a snow plow. In addition, changes to everything from control arms to the urethane bushings in the front end provide an improved, positive steering feel at all speeds.
Changes to the rear include larger asymmetrical leaf springs and a two-stage design (three on the 3500), which improves ride quality at various levels of load capacity while increasing that load capacity by up to 14% (depending on what you order).
When you redesign the engine and improve its power, you need to redesign the transmission, and the Allison 1000 is no exception. First on the list was an improved “spin loss” rating where improvements in fuel economy and power transmission come from getting more power to the drive wheels.
The horsepower and torque capacities had to be improved to handle the new 6.6 Duramax’s output. Other electronic wizardry has improved 0 to 100 km/h and quarter-mile times by 0.3 and 0.9 seconds respectively. For a truck of this size, those are huge improvements.
On the truck front, GM has made serious revisions to the frame, suspension, engine and transmission so that, while I can’t tell you that it is “all new”, I can tell you it is new where it counts.
The 6.6-litre Duramax now uses Piezo injectors running at 2,000 bar or 30,000 psi to have better control of the injection moment and improve fuel economy. In addition, changes to the intake exhaust and block make the engine quieter, run better and improve performance. On the emissions side, these changes have reduced NOx emissions by 63% over last year.
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| The 6.6-litre Duramax now uses Piezo injectors running at 2,000 bar or 30,000 psi to have better control of the injection moment and improve fuel economy. (Photo: Charles Renny/Auto123.com) |
Exhaust gas regeneration has been a contentious subject due to the frequency of regeneration and the detrimental effect it had on fuel economy. GM reports that the new system has improved by 75%, now running once every 1,100 km or so. DEF or Diesel Exhaust Fluid (a urea-based formulation) will now last about 8,000 km before needing to be topped up.
Changes to the frame have stiffened the front by about 25%, allowing any Sierra model to be equipped with a snow plow. In addition, changes to everything from control arms to the urethane bushings in the front end provide an improved, positive steering feel at all speeds.
Changes to the rear include larger asymmetrical leaf springs and a two-stage design (three on the 3500), which improves ride quality at various levels of load capacity while increasing that load capacity by up to 14% (depending on what you order).
When you redesign the engine and improve its power, you need to redesign the transmission, and the Allison 1000 is no exception. First on the list was an improved “spin loss” rating where improvements in fuel economy and power transmission come from getting more power to the drive wheels.
The horsepower and torque capacities had to be improved to handle the new 6.6 Duramax’s output. Other electronic wizardry has improved 0 to 100 km/h and quarter-mile times by 0.3 and 0.9 seconds respectively. For a truck of this size, those are huge improvements.
 |
| Changes to the rear include larger asymmetrical leaf springs and a two-stage design (three on the 3500), which improves ride quality at various levels of load capacity. (Photo: Charles Renny/Auto123.com) |