Pittdawg
Veteran Member
Darkside Developments in the UK makes a universal fit race DPF; would love to hear if anyone has tried it or something similar.
Replacing DPF CR TDI with aftermarket passive unit.
- Thread starter lorge1989
- Start date
Pittdawg
Veteran Member
That's contrary to almost every post that claims the DPF is the limiting factor; where did you get this info?
crazyrunner33
Veteran Member
The DPF isn't as limiting as you'd imagine. A SCR equipped Cummins with the DPF and a deleted Cummins experiences zero measurable increase in fuel economy. The DPFs flow pretty well if they aren't clogged, the big kicker is the EGR usage which isn't much of an issue on an SCR equipped diesel engine. The stock turbo is the biggest limiting factor. And DPF clogging typically isn't an issue on SCR equipped engines or ones with the EGR disabled.
GoFaster
Moderator at Large
A DPF needs to be close-coupled to the engine in order to minimize the need for active regeneration.
Look at where it is on a VW EA288 or on the latest M-B 4-cylinder engine. The path from the exhaust ports to the turbo to the catalyst is as short as possible and the DPF is in the same enclosure as the oxidizing catalyst.
That's not going to happen if you have connections and fittings in between, and it's not going to happen if you position the catalyst under-floor (as with the original layout of the VW common-rail TDI).
If it's tied directly to the engine, it heats up as quickly as possible and the operating temperature could reach the regeneration threshold during normal driving more frequently.
Look at where it is on a VW EA288 or on the latest M-B 4-cylinder engine. The path from the exhaust ports to the turbo to the catalyst is as short as possible and the DPF is in the same enclosure as the oxidizing catalyst.
That's not going to happen if you have connections and fittings in between, and it's not going to happen if you position the catalyst under-floor (as with the original layout of the VW common-rail TDI).
If it's tied directly to the engine, it heats up as quickly as possible and the operating temperature could reach the regeneration threshold during normal driving more frequently.
Stock size is fine
Frankly the DPF is not an impediment to power IMO so really not much to gain here, other than the possiblility of a more reliable unit.
SO if you have a chance to design an upgraded DPF, I would replace the original cordierite filter element with a silicon carbide filter medium. It will cost more than stock VW, but will not crack as it is rated for much higher temperatures
You would also need to remember the nox catalyst if you want to have a chance at compliance
If you want it to work "correctly" there are some changes needed to the ecu internal model. Can't just slap on an extra injector or something hillbilly
Frankly the DPF is not an impediment to power IMO so really not much to gain here, other than the possiblility of a more reliable unit.
SO if you have a chance to design an upgraded DPF, I would replace the original cordierite filter element with a silicon carbide filter medium. It will cost more than stock VW, but will not crack as it is rated for much higher temperatures
You would also need to remember the nox catalyst if you want to have a chance at compliance
If you want it to work "correctly" there are some changes needed to the ecu internal model. Can't just slap on an extra injector or something hillbilly