Someone here mentioned they noticed an improvement in low rpm torque with latest dealer ECM flash. Comparing the tables of each, there is some minor differences that would increase low rpm torque.
Tune map changes from original (no dealer updates) to March, 2018 dealer OS flash:
1. Amount of fuel commanded based or desired torque and rpm increased at lower rpm’s
2. Smoke Limit changed for 800 rpm’s
3. No changes in Main/Normal SOI (start of injection) tables; however, both Pre-Injection 1 and 2 tables have changes in SOI
Did not see any changes to Boost Control or Fuel Pressure; however, this was a quick look and more time is needed to verify.
The OEM tunes for both the Silverado and Colorado Diesels start rolling off (lowering) the boost and commanded fuel as rpm’s increase above 2,000 rpm’s to 2,500 rpm’s. The Colorado’s effective torque is fairly limited above 2,500 rpm’s. With some minor modifications, this can be improved. Where I notice it most is climbing mountain passes on Interstate highways at speeds over 60 mph. Pulling no trailer with either one of the OEM tunes, the truck does not accelerate or accelerates very slowly, according to the grade. With minor adjustments, it will accelerate very well from 60 mph on up until the speed limiter starts limiting. The limiter starts limiting at about 82 mph and prevents speed going over about 98 to 100 mph. Change both of these limiters to 130 mph so the limiter is out of the way. OEM tires are usually not rated for high speeds.
The recent dealer ECM flash did nothing to improve performance above 1,500 rpm's.
Tune map changes from original (no dealer updates) to March, 2018 dealer OS flash:
1. Amount of fuel commanded based or desired torque and rpm increased at lower rpm’s
2. Smoke Limit changed for 800 rpm’s
3. No changes in Main/Normal SOI (start of injection) tables; however, both Pre-Injection 1 and 2 tables have changes in SOI
Did not see any changes to Boost Control or Fuel Pressure; however, this was a quick look and more time is needed to verify.
The OEM tunes for both the Silverado and Colorado Diesels start rolling off (lowering) the boost and commanded fuel as rpm’s increase above 2,000 rpm’s to 2,500 rpm’s. The Colorado’s effective torque is fairly limited above 2,500 rpm’s. With some minor modifications, this can be improved. Where I notice it most is climbing mountain passes on Interstate highways at speeds over 60 mph. Pulling no trailer with either one of the OEM tunes, the truck does not accelerate or accelerates very slowly, according to the grade. With minor adjustments, it will accelerate very well from 60 mph on up until the speed limiter starts limiting. The limiter starts limiting at about 82 mph and prevents speed going over about 98 to 100 mph. Change both of these limiters to 130 mph so the limiter is out of the way. OEM tires are usually not rated for high speeds.
The recent dealer ECM flash did nothing to improve performance above 1,500 rpm's.
