What is an EGR?

EGR stands for exhaust gas recirculation, yes, the car takes “dirty” burnt air from the exhaust and recycles it in the combustion process. You can probably guess but the systems were introduced with the aim of improving the efficiency of the engine, in particular the EGR system reduces NOx.

Now traditionally I know that a lot of people believe that the EGR is negative for performance but that isn’t entirely true it does have the positive affect of lowering combustion temperatures. In modern diesel cars it does also feature as part of the DPF regeneration logic, by reducing the amount of NOx the DPF must regenerate less often. An engine with the EGR disabled will have to regenerate more frequently which in turn has a negative impact on economy.

The downside is that because it is flowing dirty exhaust gasses the valves can suffer carbon buildup often leading to them jamming or reduced flow. This will result in the ECU detecting a fault with the EGR leaving you with restricted performance.

The EGR solutions will remove any faults associated with the system and will command the ECU to not expect to see any airflow from the system. We would always recommend that the EGR is blanked as if it has jammed open it will have a negative effect on drivability.