Modifications of EGR/FAP/DPF systems
EGR valve (exhaust gas recirculation)
- A part found in internal combustion engines to reduce emissions of nitrogen oxides (NOx) by reintroducing a portion of the exhaust gas into the combustion chamber. The principle of the EGR valve is to redirect a certain amount of exhaust gas from the exhaust system back into the intake system, where it mixes with the air that is supplied to the cylinders. This way, the reintroduction of exhaust gases lowers the combustion temperature, which in turn reduces the production of nitrogen oxides, which are produced at high combustion temperatures. The EGR valve helps reduce the emission of harmful substances into the atmosphere, which is important because of the clean exhaust gas standards for motor vehicles.
- Software deactivation of the EGR valve involves a change in the engine controller software to prevent or disable the operation of the EGR valve. This is a practice often used in car modifications or tuning.

Without exhaust gas recirculation, the engine can be seen as cleaner because there is no reintroduction of exhaust gas into the intake system.
Removal of EGR leads to increased emissions of nitrogen oxides (NOx), which are harmful to the environment and public health.

Diesel Particulate Filters (DPF) is a key component in the exhaust system of diesel vehicles to reduce particulate matter (soot) in the exhaust. However, there can be some problems associated with the DPF, leading to considerations for its removal.
DPF issues:
- DPF can become clogged, especially if the car is frequently driven on short routes, which does not allow it to reach the temperature required for the filter to self-clean. This leads to the need for manual regeneration or replacement.
- Maintenance costs: DPF repair or replacement can be costly, and regular regeneration can be a nuisance, especially if the car is used mainly in urban conditions.
- Performance limitations: A problem with the DPF can affect a car's performance, leading to reduced power, increased fuel consumption and other problems.
DPF removal avoids the costs associated with repairing or replacing the filter. For older vehicles, it may be a cheaper alternative.
Removing the DPF increases emissions of particulate matter and other environmental pollutants. In addition, it is illegal in many jurisdictions and can lead to serious legal consequences.