HL649

Is it possible to delete the EGR but keep the DPF intact? I have a 2012 and really like the clean exhaustbut would like to get rid of the EGR.

Busboy

No, the egr is what keeps the DPF from plugging up.

Mechanos

It's all or nothing when deleting...

SOhappy

You can leave the upper cat in-place, and possibly the lower one (never heard of anyone doing that, but I don't see why not).

But keeping the DPF while ditching the EGR is like breathing cleaner air, but still having a bad case of constipation.

T210DRVR

I don't believe that cooled EGR will cause the DPF to plug. It's job is to lower combustion temperatures and this retards the formation of NOX. In theory you should have a cleaner burn with more abundant O2. The DPF is designed to reduce the amount of soot that comes from burning diesel fuel.

If I'm missing something would you mind explaining?

HL649

I have to agree. The newer trucks with Def have a reduced EGR cycle but their DPF doesn't plug up, it actually regens less. The def reduces NOX, not soot.

Busboy

I agree under normal operation the DPF filters the small bits of soot but very quickly becomes plugged. I should have said "it's the regen cycle that stops the DPF from plugging up". The regeneration cycle increases the exhaust gas temperature to very high levels and this burns out the soot, to get to these high temperatures a combination of restricting the incoming air from the precooler, EGR opening and extra fuel injection is used. When the ECM reads exhaust pressures on either side of the DPF in the normal range again the regen cycle is complete. I know from first hand experience that this system does not work in extreme cold with lots of idle time. Without the EGR opening and the intake air shut off I'm not sure what would happen to the engine with that extra fuel being injected. Even if you deactivated the intake air s/o valve in the open position the extra fuel injection couldn't possibly burn clean enough so the DPF would never regen. I have seen raw fuel running back down the boost tube and pooling at the outlet of the precooler because of the extra injection cycle during regen so it shows to me that all the fuel is not being burned and some of it finds it's way into the engine oil.