DPF, EGR explained

[Guardian29]

hello, i am new to diesels, and would like some insight on these mods. I dont expect anyone to post up a novel on these mods explained but maybe there is a thread i am missing. Just would like to know what they do, why people do them, etc. Buying my first diesel which will be the 6.7 and want to gather as much info as possible. Thanks! Also any other common mods i should know about generally done would be great, diesel specific though, ive had my share of lifted/modded trucks

[BIG Laing]

Search the entire 6.7 forums, not each section in the category.

EGR- exhaust gas recuirculator. Puts unburnt fuel and exhaust back through your motor, to burn any unused fuel. (no black smoke)

DPF - diesel particular filter. Traps soot (black smoke) that made it through. Once the filter is clogged, the truck goes into regeneration mode and burns the soot. And you get crappy gas milage for 5- 20 mins or so.

DEF - diesel exhaust fluid is basically urea, that gets injected into the SCR (?) to trap some other emissions crap.

The whole system works pretty good but is super restrictive. Intake, exhaust, and tuner = MORE POWER and better MPG.

[BIG Laing]

Oh BTW, those are not "mods", they are stock. Deleting them are the "mods".

[George C]

In order to make a diesel engine EPA compliant, the EPA looks for harmful NOx (Nitrogen Oxide) output from diesel exhaust.
NOx is a byproduct of the main power component of diesel burning engines, Oxygen.
To reduce NOx to EPA acceptable levels, exhaust gas (EGR) is re-introduced in to the engine intake to cut back on oxygen levels entering the combustion chamber.
Less oxygen to burn means less power, less economy, systematic destruction of the internal engine, high temperature and shorter oil life, but less NOx is released making the engine compliant.

The 6.4L engine relied 100% totally on EGR to make emissions, and that is why they are so inefficient stock.

2011 introduced SCR (urea) which is injected in the exhaust stream after the engine. This mixture enters a catalyst, again in the pipe after the engine. This mixture of exhaust and urea exits the catalyst with dramatically lower NOx output. This allows the engine to reduce EGR intake by over 40%, and still remain compliant.
That is why the 6.7L runs so well stock. It is allowed to actually burn more oxygen than the 6.4L, while still being EPA compliant.

Once deleted from EGR, the 6.4L becomes the best performing diesel engine on the road today. Getting rid of ANY EGR will allow your diesel to burn oxygen again, and to perform to it's potential.

[PStrokeCarioca]

Great info, thanks fellas. I'm also in the market for my first diesel (about to pull the trigger on a 6.7L) and that clears up some of the questions I had too. Once you perform all the deletes, which I plan on doing, how tough is it to find a shop to pass your emissions on state inspections?


Sent from my iPad using AG Free

[BIG Laing]

The county I live in does not do emissions testing on diesels. So idk about finding a place sorry. Check your local laws to find out if you have to do them. Although any alteration to any emissions stuff is illegal by federal and EPA laws...

[PStrokeCarioca]

Cool, thanks for the heads up. I live in Dallas TX so I should be able to find somewhere that will turn a blind eye to black smokers

[jesilvas]

I hope the cops pull over a "black smoker" Those mods will not make you smoke. You will only smoke if you're dumb and think smoke is power.
In Texas, there is no emissions testing for diesels. Like stated, all those deletes are illegal anyway.

[BIG Laing]

Ya if your going for throwing your money away in the form of smoke, you should of bought a cummins...

[JIM_C]

Can a deleted 6.7 still utilize its urea system to cut down NOx emissions to be a bit more environmentally friendly than a completely deleted 6.7? I would imagine the tuners could accommodate this.
Does this adversely affect EGTs by leaving the catalyst in the exhaust path, especially on a tuned engine?
Or maybe the SCR would get plugged up with soot. Is the urea system before or after the DPF? I would guess after ...