Attention: TDR Forum Junkies Has anyone else out there in Cummins-land noticed a change in combustion noise that occurs under cruise conditions? Very soon after I bought my truck I noticed that after about five minutes running time following my most recent gear shift, the high frequency combustion noise coming from the engine would mute, greatly reducing the sound pressure in the cab. (The first time I noticed this, it seemed like my ears had popped!)
Having once been an engineer at Cummins, I had seen an ECU parameter called Noise Control, but had never actually known what it was. So putting 2 and 2 together, I concluded that Noise Control was a function that would retard injection timing after a defined period of either no shifting of gears or nearly constant accelerator pedal position.
OK, so fast-forward 3 years, to when I finally get around to putting boost and EGT gages in my truck. Now I get to directly observe the effect of Noise Control when it activates. During my normal Interstate cruise setting of 77mph, boost runs at ~5psi and EGT runs ~700F on flat terrain with an empty truck. Then when Noise Control kicks in, boost increases to ~7psi, and EGT goes to ~775F. Neat, eh? I attribute the higher boost and EGT to late burning that puts more energy into the exhaust manifold, causing to the turbo to speed up, increasing boost, but not increasing power. Also, I have noticed that Noise Control is not affected by the program that is loaded from my Superchips tuner (from Stock to High Performance).
While I do appreciate the lower cab noise that this function gives on a long trip, I am wondering how much of a fuel economy penalty the retarded injection timing represents. Is anybody out there familiar with the workings of Noise Control, and if any of the performance modules available suppress it? I'm thinking if it can be suppressed, the fuel economy benefit would be substantial.
Thanks for your time,
Andy Harman
Having once been an engineer at Cummins, I had seen an ECU parameter called Noise Control, but had never actually known what it was. So putting 2 and 2 together, I concluded that Noise Control was a function that would retard injection timing after a defined period of either no shifting of gears or nearly constant accelerator pedal position.
OK, so fast-forward 3 years, to when I finally get around to putting boost and EGT gages in my truck. Now I get to directly observe the effect of Noise Control when it activates. During my normal Interstate cruise setting of 77mph, boost runs at ~5psi and EGT runs ~700F on flat terrain with an empty truck. Then when Noise Control kicks in, boost increases to ~7psi, and EGT goes to ~775F. Neat, eh? I attribute the higher boost and EGT to late burning that puts more energy into the exhaust manifold, causing to the turbo to speed up, increasing boost, but not increasing power. Also, I have noticed that Noise Control is not affected by the program that is loaded from my Superchips tuner (from Stock to High Performance).
While I do appreciate the lower cab noise that this function gives on a long trip, I am wondering how much of a fuel economy penalty the retarded injection timing represents. Is anybody out there familiar with the workings of Noise Control, and if any of the performance modules available suppress it? I'm thinking if it can be suppressed, the fuel economy benefit would be substantial.
Thanks for your time,
Andy Harman
