If you use the tuner to increase power or torque, fuel consumption always increases, as more fuel is supplied into the cylinders. This is especially true for operating modes for towing and transporting heavy loads in severe road conditions. In such cases, fuel consumption increases significantly. It is also possible to find the optimal modes for power and consumption, but this way, it is impossible to reveal the power potential of the engine. The Bully Dog ​​40415 and 40417 software tuners perform quite efficiently in fuel-saving modes. Consumption per hundred kilometers can be reduced if you set the appropriate modes. This applies primarily to driving on the highway when fuel consumption can be reduced to 4 liters. In fact, the tuner does work, but the consumption depends on many factors, including driving mode and conditions, proper fuel supply systems, and secondary exhaust recirculation. With all systems working together, savings can be much more significant.