A system modification for certain diesel engines involves the removal of the exhaust gas recirculation (EGR) system and the installation of components designed to bypass its function. This action is often undertaken to address perceived issues related to performance, reliability, and maintenance of the EGR system itself. The parts included typically consist of block-off plates, coolant rerouting hardware, and potentially electronic control modifications.
The rationale behind this modification often stems from concerns about decreased engine efficiency due to the introduction of inert exhaust gases into the intake manifold. Proponents also argue that disabling the EGR system reduces the buildup of carbon deposits within the intake system, potentially leading to improved engine longevity. Historically, such modifications were more prevalent in off-road or competition applications where emissions regulations were less stringent and performance optimization was prioritized.