I once built a dongle which plugged into the OBD socket of the Alfa /Vauxhaull/ Saab Z19dth engine to allow the DPF to be 'modified' and the EGR valve to be blocked off.
Â
DPF's are almost all 'wall flow' filters, (if you google it you'll get the idea), it's basically a stack of hollow tubes running lengthways and each alternate one is blocked off at the end or at the front. From the inlet side the gasses go down the open ends of the tubes, which themselves are blocked off at the rear leaving only the wall of the tube as a suitable passage.
From the outlet end you see the open tubes which have been blocked off at the front.
Some people drill a hole through them or gut them out completely, but that can cause problems with the regeneration control system which relies on pressure sensors to trigger a regen.
Â
What I had success with, was removing the caps of the tubes at the exit side of the filter cartridge, just with a long masonry drill, but only going to a depth of 3-5mm maximum. drilled off about 20% of the filter face area first, and then did a little bit more too afterwards.
It regenerated fine, with only minimal smoke after that, and meant I didn't need a new filter..
Then i got carried away and removed the whole of the rear face so that it was pretty much a free flowing exhaust and that made the ECU throw up errors as the pressure differential front to back was too small, which is why I had to make the dongle to reset the dpf regen timer every time the car was started so it never attempted a regen in the first place
Â
DPF's are almost all 'wall flow' filters, (if you google it you'll get the idea), it's basically a stack of hollow tubes running lengthways and each alternate one is blocked off at the end or at the front. From the inlet side the gasses go down the open ends of the tubes, which themselves are blocked off at the rear leaving only the wall of the tube as a suitable passage.
From the outlet end you see the open tubes which have been blocked off at the front.
Some people drill a hole through them or gut them out completely, but that can cause problems with the regeneration control system which relies on pressure sensors to trigger a regen.
Â
What I had success with, was removing the caps of the tubes at the exit side of the filter cartridge, just with a long masonry drill, but only going to a depth of 3-5mm maximum. drilled off about 20% of the filter face area first, and then did a little bit more too afterwards.
It regenerated fine, with only minimal smoke after that, and meant I didn't need a new filter..
Then i got carried away and removed the whole of the rear face so that it was pretty much a free flowing exhaust and that made the ECU throw up errors as the pressure differential front to back was too small, which is why I had to make the dongle to reset the dpf regen timer every time the car was started so it never attempted a regen in the first place
<p style="text-align:center;">Ohlins, PC3, fuel cut defeat, +4deg timing, 17" front wheel.