Dpf Is A Piece Of Junk Or The Lmm Duramax Is

Daryl Z71 · August 23, 2010

Why does he need smoke? All your doing with blowing a bunch of smoke is not burning Diesel. Whats the point?

i know its pointless, it just DUMPS fuel doesnt make any power. but one time we were at an intersection and these kids were in a civic with a subwoofer just blastin some annoying crap all their windows were down, their caps were on all sideways. they couldnt be positioned better to get smoked LOL, he flipped the switch and the light went green and POOF they were breathin out the windows and they turned their crappy music OFF and we could hear our johnny cash again. thats why he has a "smoke" tune AHAHAHA

I had a guy do that to me while on my bike......... If his punk a$$ had pulled over I would have used his broken body to clog up that smoke belching tail pipe.

hell yeah, i'll get the cummins retard with the old 24valve that had the little knob you could crank to raise fuel amount thus blowing smoke....its idiotic and pointless let alone ruining the motor...if i had a diesel that thing would be treated like gold

I couldn't agree more.

uh6tdrvr · August 25, 2010

Why does he need smoke? All your doing with blowing a bunch of smoke is not burning Diesel. Whats the point?

That is not 100% true. Some smoke is actually necessary. When you come off the line and the engine is not producing substantial airflow/exhaust energy and adding fuel can help build turbine speed more quickly in order to increase the torque during the transient (more necessary when there is no VGT, but still useful even today). Now, there is a law of diminishing returns here, but adding more and more does continue to increase this effect. And, this shouldn't hurt a DPF too terribly bad as long as your TOT is high enough to burn off the excess soot. However it usually isn't in the transient case. The soot can have negative effects on several other items in the engine though and usually make for some seriously high exhaust temperatures if the turbo is not able to eventually catch up with the amount of fuel being put in.

Actually, black smoke is wasted fuel....unless you know something that Gale Banks doesnt

btw, im not surprised that removing the DPF increased the mpg's, isnt that what most do for performance, remove whatever they can thats restrickting the in/out?

vettelovralexand · August 25, 2010

Why does he need smoke? All your doing with blowing a bunch of smoke is not burning Diesel. Whats the point?

That is not 100% true. Some smoke is actually necessary. When you come off the line and the engine is not producing substantial airflow/exhaust energy and adding fuel can help build turbine speed more quickly in order to increase the torque during the transient (more necessary when there is no VGT, but still useful even today). Now, there is a law of diminishing returns here, but adding more and more does continue to increase this effect. And, this shouldn't hurt a DPF too terribly bad as long as your TOT is high enough to burn off the excess soot. However it usually isn't in the transient case. The soot can have negative effects on several other items in the engine though and usually make for some seriously high exhaust temperatures if the turbo is not able to eventually catch up with the amount of fuel being put in.

Actually, black smoke is wasted fuel....unless you know something that Gale Banks doesnt

btw, im not surprised that removing the DPF increased the mpg's, isnt that what most do for performance, remove whatever they can thats restrickting the in/out?

I don't think Gale would say that black smoke is "wasted fuel." I think he would call it "unburnt fuel." Very substantial difference. Even fuel that is not entirely burned adds heat/energy and also mass flow to the exhaust. If he said that it was wasted fuel, maybe I do know something he doesn't.

vettelovralexand · August 25, 2010

btw, im not surprised that removing the DPF increased the mpg's, isnt that what most do for performance, remove whatever they can thats restrickting the in/out?

And on this point, did you know that adding restriction on a diesel can also increase power? Basically, when a company specs a turbocharger today they tend to make it slightly smaller than one that can ideally push as much mass flow of air as will be needed by the engine to make its peak power numbers, when there is restriction post turbo or caused by the turbo (especially one that is slightly too small) it allows the system to push exhaust gas into the intake more easily (this can usually be seen by what people call drive pressure, but what is really turbine inlet pressure vs boost pressure which is similar to turbo efficiency but not exactly as it doesn't account for temperature). While exhaust gas is virtually inert, it does also have mass and volume (you know, it is matter) and therefore increases cylinder pressures of the burn. So you use less fuel and fresh air to get the same kaboom, but more pressure results simply from the added in cylinder pressure. Most systems today will actually make less power if EGR is removed and the turbo does not replace the lost mass from the EGR. Most diesel hotrodding people will disagree with me on this because EGR makes things feel slower because they hurt transient response due to the loss of exhaust pressure caused by EGR flowing, but the actual peak numbers on an engine dyno will suffer. And, when they remove the EGR they often are pushing more boost from the turbo or have swapped the turbo anyway, so the rules are no longer the same.

Lastly, when you remove the DPF you can then eliminate the very late post injection on a diesel engine to save some fuel economy but this injection will rarely be seen as black smoke as it is injected while the exhaust valve is open and is rapidly taken from the cylinder. If it appeared as soot, it would only be due to burning from within the exhaust. Most tunes that remove the DPF don't just delete the DPF though and therefore can make much larger MPG gains than simply eliminating the last injection.

ColoradoSkiCountry · August 26, 2010

I would love to get rid of my DPF system, sadly the Enviro Nazi's where I live are very strict on that stuff when doing the mandated inspection and dyno testing.

NONSTOP SPEED · August 29, 2010

I would love to get rid of my DPF system, sadly the Enviro Nazi's where I live are very strict on that stuff when doing the mandated inspection and dyno testing.

Thats why you just get a bypass pipe it is cake to install 6 bolts and 4 sensors and your ready to go. I'm in Denver I don't worry about the emissions since mine is registered in Oklahoma. But its pretty simple to install.

ColoradoSkiCountry · August 29, 2010

Here in Denver they not only do a visual inspection to ensure that nothing has been removed or modified, they also connect up something to the onboard computer to check to ensure the system is working the way it should, so if the DPF is removed I'm sure they would know it and fail the vehicle.

I would love to get rid of my DPF system, sadly the Enviro Nazi's where I live are very strict on that stuff when doing the mandated inspection and dyno testing.

Thats why you just get a bypass pipe it is cake to install 6 bolts and 4 sensors and your ready to go. I'm in Denver I don't worry about the emissions since mine is registered in Oklahoma. But its pretty simple to install.

NONSTOP SPEED · August 30, 2010

Here in Denver they not only do a visual inspection to ensure that nothing has been removed or modified, they also connect up something to the onboard computer to check to ensure the system is working the way it should, so if the DPF is removed I'm sure they would know it and fail the vehicle.

I would love to get rid of my DPF system, sadly the Enviro Nazi's where I live are very strict on that stuff when doing the mandated inspection and dyno testing.

Thats why you just get a bypass pipe it is cake to install 6 bolts and 4 sensors and your ready to go. I'm in Denver I don't worry about the emissions since mine is registered in Oklahoma. But its pretty simple to install.

Typically they do the visual and the scan for any SES codes to make sure everything is currently working, also the reason they do them annually on diesels. It would just be a matter of putting it back on for emission testing.

uh6tdrvr · August 30, 2010

Why does he need smoke? All your doing with blowing a bunch of smoke is not burning Diesel. Whats the point?

That is not 100% true. Some smoke is actually necessary. When you come off the line and the engine is not producing substantial airflow/exhaust energy and adding fuel can help build turbine speed more quickly in order to increase the torque during the transient (more necessary when there is no VGT, but still useful even today). Now, there is a law of diminishing returns here, but adding more and more does continue to increase this effect. And, this shouldn't hurt a DPF too terribly bad as long as your TOT is high enough to burn off the excess soot. However it usually isn't in the transient case. The soot can have negative effects on several other items in the engine though and usually make for some seriously high exhaust temperatures if the turbo is not able to eventually catch up with the amount of fuel being put in.

Actually, black smoke is wasted fuel....unless you know something that Gale Banks doesnt

btw, im not surprised that removing the DPF increased the mpg's, isnt that what most do for performance, remove whatever they can thats restrickting the in/out?

I don't think Gale would say that black smoke is "wasted fuel." I think he would call it "unburnt fuel." Very substantial difference. Even fuel that is not entirely burned adds heat/energy and also mass flow to the exhaust. If he said that it was wasted fuel, maybe I do know something he doesn't.

While you can make more power with more fuel, if you don’t do it right, exhaust gas temperatures go out of sight and that can spell eventual death for the engine or turbocharger – or both. Many racers seem unaware of the potentially expensive engine damage such modifications can cause, or maybe they just don’t care. Their first consideration is how much power they can add to their diesel pickup. They are willing to assume some risk, and that’s just what you do when you overfuel a diesel. The real secret to big power increases is to add both fuel and airflow to achieve complete burning of the extra fuel (see First Air — Then Fuel elsewhere on this site). If you don’t burn the extra fuel, then you’re just overfueling. The telltale sign of overfueling is excessive smoke out of the exhaust pipe, but for a lot of diesel hot rodders, the thick black smoke is a big part of the fun.

http://www.bankspower.com/techarticles/sho...cing-the-diesel

close dc · January 12, 2016

I have a stock 2011 and would definitely say that the dpf is nothing but trouble. Now that comes after 65,000 miles of solid performance. The dpf no longer regens and I was in limp mode, which is very scary, especially in the cold valley where I live. Two dealers have run forced regens and they both lasted about 550 miles. If you are out in the middle of nowhere and enter limp mode the GM engineers would like you to know that you are screwed. I am faced with a two thousand dollar bill for a new dpf, and then I would like to get rid of this truck and get another 8.1. As for the duramax motor, it is nothing short of awesome!

mholeson · August 21, 2016

It's not the tuner. I don't have one and have a 3500 . when towing DTC in regen does not clean thrown check light . look to dealer won't cover to salt water under carriage for a 3 week vacation WTF...

Have to drive 30 going into limp have to clear. WTF