This modification involves the removal of the Exhaust Gas Recirculation system on a specific model of Duramax diesel engine. This system is designed to recirculate a portion of the engine’s exhaust gas back into the intake manifold, reducing combustion temperatures and, consequently, nitrogen oxide (NOx) emissions. The affected engine is commonly found in Chevrolet and GMC trucks manufactured during a specific period. The components typically included in this modification are block-off plates, coolant rerouting hoses or plugs, and potentially a tuner or programmer to prevent error codes.
Eliminating the exhaust gas recirculation system can offer several advantages. Some proponents suggest improvements in engine performance and fuel economy due to the elimination of exhaust gas recirculation. Furthermore, it can mitigate the buildup of soot and carbon deposits within the intake manifold, which is a common issue with the original system. Historically, this modification has been popular among individuals seeking increased power and reliability from their diesel engines, particularly in applications involving towing or performance enhancements.