MPG's with Diesel

[Salvagediver]

Originally Posted by sbowman

2016 RAM 3500 4x4 4 door long bed w/topper just under 9k w/26k. Towing loaded 19k weight in motion lowest 11.5 best 16.2. Not towing over 22. Living in the PNW we travel up and down. Not a lot of flat land.

sbowman,

Does your 2016 Cummins have the DEF injection system? Our 2019 is a Tier IV engine and therefor, of course requires DEF...(at least it doesn't go into "creep mode" if we run out on the road until the first stop).

I ask because I was talking to a diesel mechanic that mentioned that DEF injection systems rob HP and hurts MPG...I guess it makes sense if we are diluting the fuel charge even in a minor way with DEF but I am curious if you have heard or experienced anything similar. Thanks, Mark

[KK4YZ]

Originally Posted by Salvagediver

sbowman

I ask because I was talking to a diesel mechanic that mentioned that DEF injection systems rob HP and hurts MPG...I guess it makes sense if we are diluting the fuel charge even in a minor way with DEF but I am curious if you have heard or experienced anything similar. Thanks, Mark

DEF is injected into the exhaust system and used by the SCR (forgot what the acronym stands for) to break down NOx. The mechanic may have been referring to the DPF (Diesel particulate filter). When the DPF gets full of soot, the truck will send diesel fuel into the exhaust system for combustion in the DPF to burn off soot. That obviously hurts fuel mileage.

I think all of the consumer diesel vehicles have these systems since around 2010.

By the way never add DEF to your fuel tank. That stuff isn’t good for your fuel system.

[gypsydad]

Originally Posted by Salvagediver

GD,

I'm researching a means to use a logistics provider's fuel card that allows for discounted fuel purchases at Love's, Flying J, and TA and will update this thread if this works out...

Will watch for your post! Typically, those you mention are at least a dime a gallon more...sometimes 20-25 cents more...only in emergency would I stop there to fill up...

[Salvagediver]

Originally Posted by sbowman

2016 RAM 3500 4x4 4 door long bed w/topper just under 9k w/26k. Towing loaded 19k weight in motion lowest 11.5 best 16.2. Not towing over 22. Living in the PNW we travel up and down. Not a lot of flat land.



Best regards

Originally Posted by KK4YZ

The mechanic may have been referring to the DPF (Diesel particulate filter). When the DPF gets full of soot, the truck will send diesel fuel into the exhaust system for combustion in the DPF to burn off soot. That obviously hurts fuel mileage.

Thanks!! He had to have meant the DPF. That makes sense now.

BTW, I asked the Cummins rep and a Freightliner rep at the Tampa RV show today about my earlier question regarding the folklore of keeping the exhaust brake in auto...the Freightliner guy said it made sense to keep the VGT loosened up and the Cummins engineer said the same in so many words but advised against fuel additives to help lubricity of low sulfur fuel.

[KK4YZ]

Originally Posted by Salvagediver

Thanks!! He had to have meant the DPF. That makes sense now.

BTW, I asked the Cummins rep and a Freightliner rep at the Tampa RV show today about my earlier question regarding the folklore of keeping the exhaust brake in auto...the Freightliner guy said it made sense to keep the VGT loosened up and the Cummins engineer said the same in so many words but advised against fuel additives to help lubricity of low sulfur fuel.

I wonder why he advised against an additive for lubricity? Sometimes you’ll hear the engine / auto manufacturers say “no additives are needed” as opposed to advising against. The high pressure fuel pump maintains a really high pressure in the fuel rail. The pump (at least in the Ford 6.7) is a high stress item and relies on the fuel for lubrication. I believe the same is true for GM and Cummins. ULSD fuel has less lubricity than previously available fuels.

Seems to me that an additive for lubricity can’t hurt.

[gypsydad]

Originally Posted by KK4YZ

I wonder why he advised against an additive for lubricity? Sometimes you’ll hear the engine / auto manufacturers say “no additives are needed” as opposed to advising against. The high pressure fuel pump maintains a really high pressure in the fuel rail. The pump (at least in the Ford 6.7) is a high stress item and relies on the fuel for lubrication. I believe the same is true for GM and Cummins. ULSD fuel has less lubricity than previously available fuels.

Seems to me that an additive for lubricity can’t hurt.

This is an interesting topic for sure...I have been wondering about this for a while now...seeing the 10% bio-fuel posts now on diesel pumps in some locations...any experts out there care to weigh in on using additives for diesels? I must say, with 78K miles now on my rig, it still runs very smooth without any additives, but...

[Specsalot]

Originally Posted by Salvagediver

I'll admit to being a bit OCD regarding engine/drive train maintenance and always used Howes "Diesel Treat" in our Freightliner chassis based Super C but have been doing the same with our new Cummins powered Ram 2500. Fully synthetic Shell Rotella goes into the crankcase. We tow an International Serenity 30RB using a ProPride 3P 1400 and have the auto-airlift rear suspension supporting a 3.73 LSD. I also use the STP diesel treatment on occasion even though all the truckers say "nothing is needed south of I 40" Another point recommended to me was to engage the exhaust brake in Auto always...not sure if any others have been advised the same way.

I do my best to avoid bio-diesel but am wondering what you use to care for your engine a keep the injectors in shape. Thanks.

There really isn't any specific maintenance for fuel nozzles other than taking care of fuel system PM's and sourcing the best qualify fuel you can find. I run a lubricity additative that also includes a cetane booster. Why? I'll let the diesel fuel manufactures explain it. Here is their 2012 statement on fuel quality concerns. It represents industry response at the onset of increased high-pressure fuel pump failures due to fuel quality issues.

https://www.denso.com/global/en/news...tion_paper.pdf

[KK4YZ]

Originally Posted by Specsalot

There really isn't any specific maintenance for fuel nozzles other than taking care of fuel system PM's and sourcing the best qualify fuel you can find. I run a lubricity additative that also includes a cetane booster. Why? I'll let the diesel fuel manufactures explain it. Here is their 2012 statement on fuel quality concerns. It represents industry response at the onset of increased high-pressure fuel pump failures due to fuel quality issues.

https://www.denso.com/global/en/news...tion_paper.pdf

An observation of the companies that issued the joint statement: Bosch and Denso produce the High Pressure Fuel Pumps commonly found in diesel pickups. Stanadyne, while being a producer of diesel fuel pumps, is also very well know for diesel fuel additives. I started using Stanadyne Performance additive for two reasons: to help with lubricity and to help the performance of the water separator in the truck. These fuel systems produce increasingly high rail pressures and need to be babied. There’s a wealth of information on various Ford, GM and Ram diesel forums.

[Salvagediver]

Originally Posted by Specsalot

There really isn't any specific maintenance for fuel nozzles other than taking care of fuel system PM's and sourcing the best qualify fuel you can find. I run a lubricity additative that also includes a cetane booster.

https://www.denso.com/global/en/news...tion_paper.pdf

Appreciate the link...I will check it out but for now have settled on Howes Lubricator called "Meaner Power Kleaner" as at least until the next Ice Age, I do not need any anti-gel in the additive at least down here in St Pete...and our Freightliner C had tank heaters anyway and I'm not sure what we have in the Ram...I'm sure you guys may know; I would guess there would at least be a single pass heat exchanger in the fuel tank but do not know for sure (more research!!). I want more lube due ULS fuel, and a cleaner and something to eliminate any water. The 8 oz. Meaner Power Kleaner treats up to 80 gallons, I suppose that's how it is portioned because I duess the normal saddle tank size is 80 gal.

For crankcase oil I've always used Shell Rotella - and especially since there is a synthetic version of Rotella, but may look into using Amsoil since it - supposedly - is superior in heat. I idle a little bit now just prior to shutdown to cool the turbo but anything more than a minute I am told is "old school" All I care about is oil cooking down in hot passages and leaving goop due heat - that's why Amsoil is being considered. I'd like to hear if anyone out there in diesel Airstream land has a preference. Also, I have been warned multiple times now to try to avoid ideling the Cummins...as even now for warm-up that's considered "old school".

[Specsalot]

Originally Posted by KK4YZ

An observation of the companies that issued the joint statement: Bosch and Denso produce the High Pressure Fuel Pumps commonly found in diesel pickups. Stanadyne, while being a producer of diesel fuel pumps, is also very well know for diesel fuel additives. I started using Stanadyne Performance additive for two reasons: to help with lubricity and to help the performance of the water separator in the truck. These fuel systems produce increasingly high rail pressures and need to be babied. There’s a wealth of information on various Ford, GM and Ram diesel forums.

I started using Stanadyne Performance Formula on my piezo-injector equipped CRD Jeep because it quieted the engine a bit; I used Lubricity Formula on my VW diesel. It had piezo-injectors as well. The VW engine management did small pre-injections prior to main fuel to reduce combustion noise.

On the Ram Cummins, I don't think Performance Formula delivers much extra benefit because the engine doesn't turn up the RPM of the VW/Mercedes engines.

The Bosch CP3 HPFP is an all-steel pump which has flat followers that ride an excentric driven trilobed cam. The CP4.x (x=#of pistons) has an aluminium body with a more complicated roller design. This guy does a good job describing CP4 failure modes. Ball park the roller in the CP4.x runs ~ 4X engine RPM. Once the small roller has problems rolling across the cam surface, failure begins within the pump. The metal thrown off during failure contaminates the balance of the fuel system. The CP4 is much more sensitive to fuel lubricity, so the most critical protection is to boost the lubricity of the fuel.

https://www.facebook.com/watch/?v=399904020832290

The push for more HP and Torque while meeting emissions is what has driven common rail pressure from ~ 1600 bar in the CP3 design toward 2000 bar in the latest CP4 systems. I'm happy with my lower output CP3 pumped 2018 engine.

Everything has trade off's. Higher injection pressures also allows for higher compression ratio's. This translates into more power with improved engine efficiency.

[Specsalot]

Originally Posted by Salvagediver

. . .

I'd like to hear if anyone out there in diesel Airstream land has a preference. Also, I have been warned multiple times now to try to avoid ideling the Cummins...as even now for warm-up that's considered "old school".

You are doing all the right things. Synthetic oil has a more stable film strength over a wider temperature range, so it does a better job protecting parts running at elevated temperatures. Somewhere in the manual, there are cool-down recommendations (I'll have to find and post them later), I just default to 5 minutes after a run involving trailering. Idlying is less of a problem with modern engines due to better thermal management and lower chances of fuel dillution.

[Mollysdad]

Originally Posted by Salvagediver

I'm researching a means to use a logistics provider's fuel card that allows for discounted fuel purchases at Love's, Flying J, and TA and will update this thread if this works out...

I'm not involved, but I understand you can only use the card at the lanes the semi's use, not the auto diesel out front.
Here's some good information:

https://www.youtube.com/watch?v=Xc2UwKjEJz4

[PKI]

There are several posts/videos on this card. It is a debit system on your bank account. Discount seems to vary from $0.50-0.30 a gallon and they charge 10% of the savings as a fee. The charges show up as soon as they negotiate the discount. That could be almost immediately or the next day. The phone text info showes the whole savings. Your bank account will reflect the balance after the 10% savings fee is transferred to the card company.

Recommendation is to set up a second account for this capability. Have no applied. May not. It looks to be a good idea. Thought you might be able to save similar by searching for lowest price with a gas pricing App like GasBuddy, Gascubby .... , but it appears that other sources are about $0.08-0.10 less than Pilot, Flying J ... etc. The card only works at contracted stations. It's a method for the card company to increase the volume of their purchases for a better discount and pass savings to RVers. There is also supposed to be a Goodsam discount and/or a cash discount, so lots of noise, but what looks like a good deal with the card. You can use the card for other items (food, showers, oil ....) but there is no discount for those items. DEF is not discounted. Gasoline is not discounted. Only diesel is discounted.

Above is call hearsay. Post your personal experience. Pat

[Salvagediver]

Originally Posted by Specsalot

You are doing all the right things. Synthetic oil has a more stable film strength over a wider temperature range, so it does a better job protecting parts running at elevated temperatures. Somewhere in the manual, there are cool-down recommendations (I'll have to find and post them later), I just default to 5 minutes after a run involving trailering. Idlying is less of a problem with modern engines due to better thermal management and lower chances of fuel dillution.

Oh yea, I have to actually READ the Owner's Manual..oh sorry, the "User Guide"...the recommended idle times are on page 144 and your five minutes is the recommendation after pulling max GCWR on a uphill grade. Now to find the after market FOP and LOP

[gypsydad]

Originally Posted by PKI

There are several posts/videos on this card. It is a debit system on your bank account. Discount seems to vary from $0.50-0.30 a gallon and they charge 10% of the savings as a fee. The charges show up as soon as they negotiate the discount. That could be almost immediately or the next day. The phone text info showes the whole savings. Your bank account will reflect the balance after the 10% savings fee is transferred to the card company.

Recommendation is to set up a second account for this capability. Have no applied. May not. It looks to be a good idea. Thought you might be able to save similar by searching for lowest price with a gas pricing App like GasBuddy, Gascubby .... , but it appears that other sources are about $0.08-0.10 less than Pilot, Flying J ... etc. The card only works at contracted stations. It's a method for the card company to increase the volume of their purchases for a better discount and pass savings to RVers. There is also supposed to be a Goodsam discount and/or a cash discount, so lots of noise, but what looks like a good deal with the card. You can use the card for other items (food, showers, oil ....) but there is no discount for those items. DEF is not discounted. Gasoline is not discounted. Only diesel is discounted.

Above is call hearsay. Post your personal experience. Pat

Interesting...I watched the video also....lots to consider: no set discount, separate account for this card (makes sense if your going to get it), then researching which stations honor it. I just don't like waiting in a line with semi's...for 5th wheelers with big rigs seems like it may make sense. I still like the convenience of standard gas stations for my diesel needs while on the road...like I said, the Pilots and FJ's seem to always be at least .10 to .30 cents/gal higher anyway from my experience.

[KK4YZ]

Originally Posted by Specsalot

I started using Stanadyne Performance Formula on my piezo-injector equipped CRD Jeep because it quieted the engine a bit; I used Lubricity Formula on my VW diesel. It had piezo-injectors as well. The VW engine management did small pre-injections prior to main fuel to reduce combustion noise.

On the Ram Cummins, I don't think Performance Formula delivers much extra benefit because the engine doesn't turn up the RPM of the VW/Mercedes engines.

The Bosch CP3 HPFP is an all-steel pump which has flat followers that ride an excentric driven trilobed cam. The CP4.x (x=#of pistons) has an aluminium body with a more complicated roller design. This guy does a good job describing CP4 failure modes. Ball park the roller in the CP4.x runs ~ 4X engine RPM. Once the small roller has problems rolling across the cam surface, failure begins within the pump. The metal thrown off during failure contaminates the balance of the fuel system. The CP4 is much more sensitive to fuel lubricity, so the most critical protection is to boost the lubricity of the fuel.

https://www.facebook.com/watch/?v=399904020832290

The push for more HP and Torque while meeting emissions is what has driven common rail pressure from ~ 1600 bar in the CP3 design toward 2000 bar in the latest CP4 systems. I'm happy with my lower output CP3 pumped 2018 engine.

Everything has trade off's. Higher injection pressures also allows for higher compression ratio's. This translates into more power with improved engine efficiency.

Do you feel better additives exist for added lubricity and water deemulsification than Stanadyne? What do you recommend for a CP4 equipped diesel like the 6.7L ford?

[sbowman]

Originally Posted by Salvagediver

sbowman,

Does your 2016 Cummins have the DEF injection system? Our 2019 is a Tier IV engine and therefor, of course requires DEF...(at least it doesn't go into "creep mode" if we run out on the road until the first stop).

I ask because I was talking to a diesel mechanic that mentioned that DEF injection systems rob HP and hurts MPG...I guess it makes sense if we are diluting the fuel charge even in a minor way with DEF but I am curious if you have heard or experienced anything similar. Thanks, Mark

Yes 2016 1st year for DEF. No I have not. This is our 1st diesel and RAM. Have always been a Ford big block guy 40 years. We did a lot of research. I truly believe you can not beat a Cummins. The straight 6 is a tried and true engine. Others seam to change every few years. Others will differ and that is ok.



Best regards,

[Aviator]

RAM 2020 1500 Ecodiesel. We got a solid 13mpg towing our 34' to Canopener and back to Atlanta. I expect to get 15ish when towing our 27' as it is 4000# lighter, but I won't know for sure until after the FarmLife Rally in FL.

[KK4YZ]

Originally Posted by Aviator

RAM 2020 1500 Ecodiesel. We got a solid 13mpg towing our 34' to Canopener and back to Atlanta. I expect to get 15ish when towing our 27' as it is 4000# lighter, but I won't know for sure until after the FarmLife Rally in FL.

Go Boilers! See you at Farm Life!

[jeffmc306]

Originally Posted by Aviator

RAM 2020 1500 Ecodiesel. We got a solid 13mpg towing our 34' to Canopener and back to Atlanta. I expect to get 15ish when towing our 27' as it is 4000# lighter, but I won't know for sure until after the FarmLife Rally in FL.

Aviator, we've been waiting for a new RAM 1500 Ecodiesel to weigh in, congratulations on snagging one!

How does it feel under acceleration compared to your F150 gas? What's your door sticker's payload number? Post some photos!