Try running a marathon where you can only exhale through a straw. You’ll probably succeed, but you won’t set a record. That is why some people choose to remove the catalytic converter, particulate filter or OPF filter. Without the exhaust gas filters, the engine can exhale more freely and therefore produce more power. And sometimes the filter is broken and it is cheaper not to install a new one. But is that actually allowed?
The above-mentioned filters clean the exhaust gases and thus reduce emissions. That is why in many cases it is not allowed to drive without it, but there are exceptions. We made inquiries and research at the RDW, below we list our findings regarding the removal of exhaust gas filters. We only look at the inspection requirements of the MOT, not at what the police may think about it.
Can you remove the catalyst?
The RDW allows you to remove the catalytic converter from certain cars up to a certain year of manufacture. If you have a car from 1993 or younger and you have a catalyst, then it must function properly. A missing catalyst does not function logically well. Since 1996, the catalytic converter has been mandatory for every new car with electronic ignition. If your car is old enough, you can remove the cat.
Can you remove the particulate filter (DPF)?
A particulate filter, also called DPF (Diesel Particle Filter), is allowed with a diesel older than 2017 can be removed without further problems. After this you have to go to the RDW to have the car inspected for 70 euros. It is then calculated how much extra particulate matter surcharge you have to pay per month to compensate for the extra emissions.
Can you remove the OPF (particle filter)?
The relatively young Otto Particle Filter (OPF) can be found in modern petrol engines. According to the RDW, the OPF is tested for functionality via the car’s computer. If the car gives an error message, it will not pass the inspection. Handy tuners that write the error code of the OPF from the on-board computer when removing it, so you can usually pass the inspection without this filter. These rules may change.
Can you just remove the filters?
Most cars still function fine (and often even better) with one less filter in the exhaust, but you have to be careful that your car is not rejected. If you make any legal adjustments, it is wise to have the engine readjusted. By telling the ECU what to do, you get the most out of your new exhaust system.
