Originally Posted by fujii13
Why will emissions go way up? It's burning the same amount of soot (just all the time, instead of infrequent bursts), and with a proper tune the fuel injectors wont be squirting fuel into the exhaust to burn off the soot. I'd say overall emissions will go down and DPF is just to make it so you don't see dirty black soot out of the exhaust.
To clarify what Chitty responded with, the DPF stores soot permanently. It doesn't store it for a little while and then empty itself during a regen cycle.
Soot is the result of incomplete fuel burn, which is an inherent part of burning diesel fuel: it burns slowly, which is a challenge for piston diesel engines since they require rapid, frequent combustion events to produce power.
The DPF stores soot, and the regen cycle adds heat (by way extra fuel into the DPF) t to "complete" the burn, which turns the stored soot into stored ash. The DPF has a finite life: when it's full of ash, it needs to be replaced. Little or no soot stored in the DPF is ever emitted.
Removing the DPF will result in a huge increase in emissions, and the worst kind too, since soot is much more immediately harmful than greenhouse gasses. Also, unless you also remove the catalytic converters downstream of the DPF, I suspect that they would become clogged with soot rather quickly.