2023 Ram 2500 Cummins 6.7 DPF

[Dean2]

You can also reduce the number of regens by using the gear limiter and running higher RPMs, you don't need to get up to 70 mph to clear the filter. The older Cummins produced max torque at 1500 rpm, had 6 speed auto or manual transmission. The current version produces max torque at 1800 rpm. Most of the time they are loafing along at 1200 rpm when being daily driven with no load.

The issue with modern diesels that aren't being worked, is they are basically being lugged and not run at the top of their torque band enough because of the prevalence of automatic transmissions. This causes more soot to start with and does not get the exhaust hot enough to clear. If you use your gear limiter to run the engine at 1800 to 2400, max HP is at 2800 rpm, you will get way less regens. The cleaners are just a bandaide for not running the diesel in the correct rev ranges.

 

[2003F350]

You can also reduce the number of regens by using the gear limiter and running higher RPMs, you don't need to get up to 70 mph to clear the filter. The older Cummins produced max torque at 1500 rpm, had 6 speed auto or manual transmission. The current version produces max torque at 1800 rpm. Most of the time they are loafing along at 1200 rpm when being daily driven with no load.

The issue with modern diesels that aren't being worked, is they are basically being lugged and not run at the top of their torque band enough because of the prevalence of automatic transmissions. This causes more soot to start with and does not get the exhaust hot enough to clear. If you use your gear limiter to run the engine at 1800 to 2400, max HP is at 2800 rpm, you will get way less regens. The cleaners are just a bandaide for not running the diesel in the correct rev ranges.

And take a big hit in fuel mileage. I'd rather deal with regens occasionally, than lose quite a bit of mileage.

But yes, running in a lower gear does get the revs up high enough to either force a regen or activate a passive regen.

 

[Dean2]

And take a big hit in fuel mileage. I'd rather deal with regens occasionally, than lose quite a bit of mileage.

But yes, running in a lower gear does get the revs up high enough to either force a regen or activate a passive regen.

Actually you are incorrect. Your Cummins on the highway at 65 mph in top gear, will be turning between 1800 and 2200 rpm depending on diff gears and transmission. That is also where you get your best milage. Ram went to a lot of trouble setting up the transmission, diff gear etc ratios to have it run in that rpm band.

Diesels do not get better mileage being lugged, and lugging them creates a lot of other issues.

I drove tractor trailors when I was young, you never ran them below their torque spot, back then it was 1600 to 2100. Upshifted at 2100, down shifted at 1600. Give it a try, use the gear limiter to keep the rpm in the range I suggested and I bet you get better mileage not worse. I do the same with my gas motor, limit it to 4th gear for around town, get a lot better mileage on the gas job too.

 

[NotSoFast]

Does anybody know what the failure modes for a diesel particulate filter are? Does something like **** that won't burn off clog them up? Or does the material collapse? Or? Mine seems to clog up every day or so and then either burn off while towing at 70 mph or during a regen. Towing at 50 mph, even with hills, doesn't clean it up.

 

[2003F350]

Actually you are incorrect. Your Cummins on the highway at 65 mph in top gear, will be turning between 1800 and 2200 rpm depending on diff gears and transmission. That is also where you get your best milage. Ram went to a lot of trouble setting up the transmission, diff gear etc ratios to have it run in that rpm band.

Diesels do not get better mileage being lugged, and lugging them creates a lot of other issues.

I drove tractor trailors when I was young, you never ran them below their torque spot, back then it was 1600 to 2100. Upshifted at 2100, down shifted at 1600. Give it a try, use the gear limiter to keep the rpm in the range I suggested and I bet you get better mileage not worse. I do the same with my gas motor, limit it to 4th gear for around town, get a lot better mileage on the gas job too.

I will respectfully disagree, running at 65 I average 22, at 55 I pull down 24. When I manually shift it down to 5th, my mileage drops off considerably more.

I don't disagree that diesels do better running in their torque band, but the reality is there is no way for me to legally run 65 mph most days, and that running higher RPMs doesn't net me better results. I've been driving this route in this truck for over a year and a half and have experimented with different combinations.

 

[oledirteh]

Does anybody know what the failure modes for a diesel particulate filter are? Does something like **** that won't burn off clog them up? Or does the material collapse? Or? Mine seems to clog up every day or so and then either burn off while towing at 70 mph or during a regen. Towing at 50 mph, even with hills, doesn't clean it up.

are you getting a CEL? If so are you under warranty? take it in. you have a issue regardless. what year is your truck.

 

[NotSoFast]

It's a 2020 6.4 liter. I have about 77,000 miles on it, over 2/3 of it towing.
The DPF has been giving me issues for a few years, but it's getting worse.
I can't tell yet whether the engine is putting out more crud or if it is the filter failing.

 

[nlambert182]

Assuming you mean a 6.7?

The engine isn't putting out anything more than usual. Sounds like something is failing. My suggestion is also to take it in and let the dealer diagnose it.

 

[NotSoFast]

Sorry. Yes the 6.7 liter.

 

[Grams]

I was actually wondering how the regen cycle raises the exhaust filter temperature. Does it make the fuel mixture richer? Raise the rpms?rpms?
As for DEF and nitrous oxide, all internal combustion engines produce nitrous oxide: it happens when nitrogen in the air gets burned in the cylinders. Higher pressure (like diesels) produce even more NO2.
Beats me how the DEF (a mixture of mostly water and a little urea) manages to convert the nitrous to something else. And because it is added pretty late in the exhaust stream, it probably wouldn't have much effect on the engine.

Gas engines have catalytic converters full of platinum that convert the NOx etc.

The DEF converts the Nox to water and Nitrogen. This has nothing to do with the DPF which is a soot-collector/burner and uses extra diesel-fuel injected into the engine-exhaust to incinerate the built-up soot in the DPF.

It’s all about letting us drive around burning diesel-fuel but allowing us all to avoid lung cancer and still see the sky if we do. (I’ll never forget the first time I drove I-10 and topped that last hill and saw my first-ever view of Los Angeles in 1976….. a valley of yellow-cloud / smog with a couple of building-tops sticking up out of it. Also as a school-kid in Houston having to hold my breath as I boarded the city-bus to ride home after school. The difference today is amazing.)

 

[nlambert182]

Like I said... until every country follows suit (which countries like China will never do), we're not avoiding anything. You get Saharan dust in Texas, as do we in Alabama. Imagine what else is still coming over here.

 

[jejb]

Gas engines have catalytic converters full of platinum that convert the NOx etc.

The DEF converts the Nox to water and Nitrogen. This has nothing to do with the DPF which is a soot-collector/burner and uses extra diesel-fuel injected into the engine-exhaust to incinerate the built-up soot in the DPF.

It’s all about letting us drive around burning diesel-fuel but allowing us all to avoid lung cancer and still see the sky if we do. (I’ll never forget the first time I drove I-10 and topped that last hill and saw my first-ever view of Los Angeles in 1976….. a valley of yellow-cloud / smog with a couple of building-tops sticking up out of it. Also as a school-kid in Houston having to hold my breath as I boarded the city-bus to ride home after school. The difference today is amazing.)

For a time, it was all about that. And it was a good thing. But now, IMO, it's all about making ever more complex ICE vehicles less attractive to buyers so that they will be forced into the govt mandated EV world. We are already at the point where a newer diesel pickup can't be used as a daily driver w/o likely issues with the DPF.

 

[BigLazer4u]

I highly doubt these engines will last with all this emissions stuff on them now.

 

[nlambert182]

I highly doubt these engines will last with all this emissions stuff on them now.

They will, and they still do. The emissions system may need work if you want to keep it, but the engines are fine.

 

[Grams]

For a time, it was all about that. And it was a good thing. But now, IMO, it's all about making ever more complex ICE vehicles less attractive to buyers so that they will be forced into the govt mandated EV world. We are already at the point where a newer diesel pickup can't be used as a daily driver w/o likely issues with the DPF.

I’m not a believer in gov’t conspiracies…. only anarchist’s conspiracies bother me.

 

[nlambert182]

I’m not a believer in gov’t conspiracies…. only anarchist’s conspiracies bother me.

Unfortunately, it's no conspiracy. Up until May of this year I did some work with/for the Gov't that involved trying to switch over a multitude of different things to electric.

One of those particular contracting companies bragged about how they were sole sourced to the Gov't for the next 50 years. That is not a typo. For the next 50 years, that is the ONLY company that can provide the equipment to the Gov and they are also the same company that audits certain systems to tell them what needs to be upgraded. The Gov't them goes out and requests that money from congress and then instead of bidding out the work they pay the Army corps another 20% markup to go out and do the installs.

It is 100% a racket at this point.

 

[Grams]

Unfortunately, it's no conspiracy. Up until May of this year I did some work with/for the Gov't that involved trying to switch over a multitude of different things to electric.

One of those particular contracting companies bragged about how they were sole sourced to the Gov't for the next 50 years. That is not a typo. For the next 50 years, that is the ONLY company that can provide the equipment to the Gov and they are also the same company that audits certain systems to tell them what needs to be upgraded. The Gov't them goes out and requests that money from congress and then instead of bidding out the work they pay the Army corps another 20% markup to go out and do the installs.

It is 100% a racket at this point.

The problem isn’t the agencies…it’s the big corporation-lobby who pays to keep their flunky politician in-office to create the law that govern’s the bid-process and allows a 50-yr monopoly. Follow the money!

 

[nlambert182]

It's all of the above. Been in this business for far too long and have seen it far too often.

 

[jejb]

The problem isn’t the agencies…it’s the big corporation-lobby who pays to keep their flunky politician in-office to create the law that govern’s the bid-process and allows a 50-yr monopoly. Follow the money!

I think it's the agencies too. They want to keep their jobs, pay their mortgage, buy groceries, etc. If they didn't keep finding new boogieman's to scare us with, a lot of them would be out of a job.