All cars manufactured need to fulfill an emission law that the vehicle (/engine) keeps its tailpipe emission below a given threshold. Most functions and strategies that are used to lower emissions are not always the functions that cause the lowest gas mileage. For instance a DPF (Diesel Particle Filter). To clean the Diesel Particle Filter the engine computer needs to clean this filter with (in most cases) fuel (See DPF OFF for more information).

Besides exhaust after treatment functions, the engine calibration it self (ignition timing or start of diesel injection, fuel mixture and variable valve timing) must be set in a way the vehicle will pass with lowest number of emissions. The engine calibration can be the most environment friendly but doesn’t have to be the calibration that gives the best fuel economy. Several parameters can be changed to improve gas mileage to an engine calibration. Karreman Engineering is able to re-calibrate the calibration inside the engine ECU to give you the best gas mileage. Please contact us to see what we can do for your car.