Diesel Particulate Filter

What about my Diesel Particulate Filter (DPF/FAP)?

The DPF is called Diesel Particulate Filter or in French FAP (Filtre à Particules).
This DPF eliminates diesel particles by filtering them before going out of the exhaust. You need to understand that if not any diesel smoke is coming out of the exhaust, at a certain time the filter will be full, blocking exhaust gasses with the associated power losses. To clean the filter there is a system called regeneration, meaning :

  • Natural regeneration:
    • This is done by the car itself at certain conditions
    • These conditions are at an exhaust gas temperature of 650°C and during constant speed for +/- 20km
  • Forced regeneration:
    • This is done at the dealer by sending a special program from their diagnostic unit to do the regeneration
    • The diagnostic system controls how much % that the DPF is cleaned during the process.
    • If the system notices that the % level stays too high, it will advise to replace the filter

As you can see, the problem for naturally regeneration is the high temperature of 650°C of exhaust gas. Due to the current traffic and restrictions, we may only drive 30/50/70/90/120 km/h or whatever and mostly we will drive at low RPM in a higher gear and consequently we will rarely reach the 650°C.

Therefore we advice:

  • To drive a minimum of 20 km, let's say every 2 weeks in a lower gear revving above 3000 rpm and at a constant speed. This should start the regeneration.
  • To choose always a good quality of diesel, which will give already less particles from the beginning.
  • To use regularly a good cleaning product like "FORTE diesel conditioner", which helps to reach the 650°C necessary for regeneration

Stopping the engine during the regeneration process can be worse. On some cars there is a control light, indicating you if the regeneration is busy or not, but on most cars you don't have that.

Newer versions have or will have an additional product that helps to start the chemical regeneration at a lower temperature of 250°C, but for the moment most cars don't have it.

The question is also : will tuning affect the life time of my DPF?   If the tuning is well done in function for a version with DPF, it will not or almost not affect. If it is a good tuning program it may shorten the lifetime only by 10% maximum.


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