All modern 4x4's sold in Australia have a Diesel Particulate Filter ( DPF ) in their factory exhaust system.
A DPF is a device designed to remove diesel particulate matter or soot from the exhaust gas of a diesel engine.
Most DPF's remove around 80% of the soot in the exhaust gas, some 100%.
A DPF captures the soot and stores it until is reaches a certain level normally around 70% . It then performs a filter regeneration by injecting unburnt fuel into the filter which then ignites & blasts / burns the soot into smaller particles before passing them out into the atmosphere.
Other types work on a regular smaller regeneration but still does the same thing.
DPF's can be problematic for a number of reasons, issues with the vehicles DPF software, poor quality fuel, injection pressure, etc.
Australian Emission laws prohibit the removal of a vehicles DPF - a driver/owner of a vehicle that has had the DPF removed can face hefty fines if caught. The person/company who actually did the DPF removal can also be fined.
When a DPF is removed an ECU edit needs to be performed removing all knowledge of the DPF & its sensors - the cost of an edit can be in the region of $700.
If you delete the DPF from your 4x4 & then need to have a Roadworthy, Blue Slip etc the vehicle should fail as it is not compliant with Australian Emission laws. The only way of passing these inspections would be to restore the factory DPF & retune the ECU back to factory section. This can be an expensive exercise !
As a reputable exhaust manufacturer we do not recommend customers remove the DPF on their vehicle - there is very little difference in performance, it all depends on the correct tune of the individual vehicle as to how it performs.
Please do not hesitate to call us to discuss further.