DEF Consumption?

[vlamgat]

Just finished a 2500 mile trip and was surprised to find that DEF "range" was about that amount. I used a 1/2 tank for about 1300 miles per the gauge and augmented the tank with a 2.5 gallon box purchase and a frustrated purchase at a truck stop.

Wonder what others are seeing? My 2014, Ford F550 6.7 PSD Born Free of a similar weight to the 28SS saw about twice the range from a 7 gallon tank vs the RAM 9 gallon capacity.

I have to find the exact stopping point for a truck stop hose to reach both the gas tank and the DEF tank. There is a point I suspect that works for both but I have yet to find it.

Then there is back and forth to the cashier and the overcharge if a second CC swipe is needed for DEF. Not sure how to avoid that without an extended stop to the amusement of the 18 wheeler stacked behind. I never used the truck fill DEF with the F550 because it used so little.

[halla]

I have the TSD rv card, lets me fuel and use def in the truck lanes, plus we get a discount. So far I have not had issues filling fuel and def.

Range, I dont really gauge it but your summary seems close to what I use.

[I5PhilGa]

Originally Posted by vlamgat

Just finished a 2500 mile trip and was surprised to find that DEF "range" was about that amount. I used a 1/2 tank for about 1300 miles per the gauge and augmented the tank with a 2.5 gallon box purchase and a frustrated purchase at a truck stop.

Wonder what others are seeing? My 2014, Ford F550 6.7 PSD Born Free of a similar weight to the 28SS saw about twice the range from a 7 gallon tank vs the RAM 9 gallon capacity.

I have to find the exact stopping point for a truck stop hose to reach both the gas tank and the DEF tank. There is a point I suspect that works for both but I have yet to find it.

Then there is back and forth to the cashier and the overcharge if a second CC swipe is needed for DEF. Not sure how to avoid that without an extended stop to the amusement of the 18 wheeler stacked behind. I never used the truck fill DEF with the F550 because it used so little.

The DEF gauge in my 2019 Isata 5 36DS is definitely not linear. Adding 5 gal of DEF brings the gauge from the “low” mark to dead on the full mark. The tank will then easily take 2+ gallons to fill completely. I now average between 300 and 350 miles per gallon of DEF, depending on how much idling / stop and go traffic. When new, it barely got 250 miles on a gallon. I don’t like to keep too much DEF in the tank as I may go 3 to 4 months without driving it. The process to remove old DEF from the tank is a pain!

[vlamgat]

Originally Posted by I5PhilGa

The DEF gauge in my 2019 Isata 5 36DS is definitely not linear. Adding 5 gal of DEF brings the gauge from the “low” mark to dead on the full mark. The tank will then easily take 2+ gallons to fill completely. I now average between 300 and 350 miles per gallon of DEF, depending on how much idling / stop and go traffic. When new, it barely got 250 miles on a gallon. I don’t like to keep too much DEF in the tank as I may go 3 to 4 months without driving it. The process to remove old DEF from the tank is a pain!

The owners manual for the RAM C&C is quite specific about the gauge not reading a linear capacity which they define as a "reserve" over the indicated FULL amount.

Interesting that your consumption rate has improved - I will look for that as I get past my current 5K.

I never had any issues with DEF use in the F550 despite a much slower rate of consumption that resulted in barely one 7 gallon tank usage a year for 12,000 miles. With frequent 2 day journeys of 1200+ miles, I guess I wont have an aging problem.

[rzr4playtime]

2018 1 ton DRW Chevy pull 14k, Ohio to Colorado (Silverton) and return, 1 gal per 400 miles, using cruise majority of the time. Definitley concerning. Later found on line others getting similar consumption.

[Lvnthedream]

I get about 280 DEF MPG tracking this 5 times so far. Like hella said, I have a EFS card which allows fueling at the truck stops without going in and prepaying. Additionally, you get a discount on fuel. The discount and convenience is well worth the application process. You have to fuel first and than add DEF. I have my wife back up a little so the DEF hose will reach.

[The Evil Twin]

Across all manufacturers, the dose rate for DEF is an average of 2% of the fuel consumed. Some more, some less. So for every 50 gal of diesel you can assume 1 gallon of DEF was used.

[milkman55]

Here is what the Cummins Website says about DEF consumption which confirms the 2% of fuel consumed guideline but it does say the loading on the chassis is a factor. Since most of us run close to the 19,500 lbs and also pull a vehicle, we probably put more load on the Cummins than say a RAM 3500 pickup.

[vlamgat]

Originally Posted by milkman55

Here is what the Cummins Website says about DEF consumption which confirms the 2% of fuel consumed guideline but it does say the loading on the chassis is a factor. Since most of us run close to the 19,500 lbs and also pull a vehicle, we probably put more load on the Cummins than say a RAM 3500 pickup.

Thanks Milkman55 for that - confirms my observations which as I wrote, about 2X the Ford F550. My guess is that the Cummins is a a higher state of tune than the Ford, using higher boost and demanding more "cleaning". Road and weather conditions about the same but over 60,000 miles in the Ford I had plenty of opportunities to measure and observe.