The removal of the exhaust gas recirculation system, or EGR, is a modification performed on vehicles to disable or eliminate this emissions control component. This system is designed to recirculate a portion of an engine’s exhaust gas back to the engine cylinders. The purpose is to dilute the intake charge and lower peak combustion temperatures, thereby reducing the formation of nitrogen oxides (NOx), a regulated pollutant. Its elimination involves physically removing the EGR valve and associated components, and often reprogramming the engine control unit (ECU) to prevent error codes and optimize engine performance.
Historically, disabling this system has been pursued for several reasons, including perceived improvements in engine performance and fuel economy, particularly in older diesel engines. Some believe that recirculating exhaust gas introduces soot and other contaminants into the intake manifold, potentially leading to decreased engine lifespan or efficiency. Furthermore, the system can become prone to failure over time, leading to costly repairs. The practice, however, has significant environmental implications due to the increased NOx emissions it causes.
