Lately we have been deep diving into Indian Motorcycles, Specifically the New Chief 2021+ Models. The Engineers at Indian Motorcycles certainly like to do things differently to the Engineers at Harley Davidson. The way they have set up the ECU Strategies for the INDIAN Chiefs took some time to understand and develop our knowledge, but once you get your head around it, they do become quite satisfying to tune.
The common problem with both Harley Davidson’s and Indians is that they are V-Twin Engines with a shared Intake Manifold. The issue with this, from a tuning standpoint, is that both cylinders do not receive the same airflow, therefore, they will have different Fuel Requirements. Hence why we tune both cylinders individually on a V-Twin Engine in order to gain a smooth and crisp to quick throttle movement.
One of the other areas we are able to make great improvements with these INDIAN’s is the Torque Control Mapping. The Factory Engineers have set up Calculated Torque Mapping based on the Engine Size, Throttle Position, Volumetric Efficiency and more, but when you change the Intake, Exhaust, or Camshaft, you are changing some of these data points. What this means is that without adjusting the Maximum Torque Output Tables within the ECU, the bike will maintain the factory torque limits by closing the throttle blade.
When adjusting these torque limits from 4500 rpm to 5300 rpm, it makes nearly 20Hp difference when compared to stock.