To "delete" or not to "delete"

ShinerBock wrote:

6.6 Oilburner wrote:


What?!?! Thats the most foolish thing I have heard. The purpose of the Diesel particulate filter is to reduce emissions, as is the EGR. The DEF is intended to make regens cooler and healthier.

Well I am sorry if the truth sounds foolish to you, but it is true.

Diesel particulates are not necessarily harmful to the environment(as in the ozone), but are very harmful to people. They cause a whole host of respiratory issues and contains multiple particle that are very carcinogenic(causes cancer). I remember reading an internal newsletter when I was at Cummins about an study done by another group on how likely you are to have respiratory health issues the closer you live to major highways. If I recall correctly it was a very substantial increase the closer you live to these highways. Some people tend to think that they are somehow getting back at a Prius driver when they purposely emit black smoke, but in reality all they did was raise the chances of those around them getting some for of respiratory illness in the long run especially in the elderly. Oh, and they also caused the rest of us money via taxes (since we pay for Medicare) and through higher insurance premiums since respiratory illness like lung cancer costs out the wing wang(which makes our health insurance rise).

Due to the compression ignition of a diesel, diesel particulates are very fine and can easily get trapped in small places of your lungs. This is why Diesel Particulate Filters(DPFs) are used to trap the fine particles, collect them, and then burn them off as ash to store in the filter. This is why the new diesels do not emit black smoke.

The EGR and SCR/DEF systems are there to remove nitrogen dioxide/nitrogen oxide(NOx) from the exhaust. NOx is very harmful to the environment and humans. It dissolves in moisture in the atmosphere causing acid rain. With the old engines like the OP has that had an EGR as their only means to reduce NOx, the EGR system was always being used to introduce cooled exhaust gas in order to lower combustion temps which lowers NOx. The drawback to this is that it creates more soot which clogs the DPF filter quicker, and it doesn't allow the engine to run at optimum temperature therefore cutting power and efficiency.

With the new SCR and EGR combination in the new engines(GM & Ford 2011+/Ram 2013+), the EGR is only used at startup when the SCR catalyst is not hot enough. Once the SCR is hot enough, the EGR valve shuts and turns the job of removing NOx to the SCR which turns it into harmless water vapor and nitrogen. Since the EGR is not being used as much and the NOx removal is outside of the engine; this allows Cummins to tune the engine for optimum power and efficiency. The higher combustions temps also create less soot which clogs the DPF less which in turn requires less regens further increasing efficiency.

So I will say it again, the DPF is there mostly for human health while the EGR and SCR/DEF system is there for mostly environmental reasons.

Also, remember to thank the next person you see "rolling coal" for not only increasing your chances of health issues, but also costing you money just so they can be in the "cool club" and selfishly not care about those around them. Don't get me wrong, I am all for people being able to do what they want to do just as long as what it is that they want to do does not effect anyone else in any negative way. You want to blow black smoke? Sure, then just reroute the exhaust to your cab and put your A/C on recirculate. If you are not willing to do that then why are you willing to blow that **** on me or my family increasing our chances for an illness we can't afford when we get older?

Great post ShinerBock and 100% correct in everything you said. You're either a smog tech or someone really in the know.

And just to clear up a few misconceptions for some on here.

Just because you don't roll coal DOES NOT mean your truck engine is clean. That's like saying my big block I race is in perfect tune and does not smoke so therefor it is a "clean engine." Nothing could be further from the truth! In fact a "detuned engine" will be waaaaaay cleaner (NOX wise) than a really good running, well tuned lean burn engine.

There are several types of pollutants that come out of an engine. For a diesel two of the big ones are particulate matter (the black soot you see) and NOX (the stuff you can't see). Both are bad.

Since diesels at cruise or idle are a lean burn engine, they put out a lot of NOX. That's why when tuners really get an efficient burn on the diesel engine the NOX goes sky high but you pick up some mileage. The burn is great and the mileage is great but the pollution is sky high.

When you put a lot of fuel to a diesel to make power without the air to clean things up, they put out a lot of particulate matter. This is also bad but for a different reason as SB has pointed out.

In short there are several types of pollution: Some you can see with your eyes and some you can't see with your eyes. Just because the tune on your truck's diesel engine does not roll coal does not mean it's clean smog wise.