DEF use

[46490]

On a current trip from lower 48 to Alaska.
Used about 10 gallons of DEF in 3,000 miles. Allot of hills and slow speeds. Averaging about 10 mpg towing a ford focus and speed is about 50mph due to road conditions. I have a 13.5 gallon DEF tank and a 6.7ISB motor. This is for all of us wondering mpg to DEF usage. Once the trip is done I will post the exact usage for all to see.

[traveler of california]

Your experience sounds very similar to mine.

[Fiesta48]

I get 375 miles per gal of DEF, if I'm driving highway speeds. On my 8.9l ISL. Rarely see regeneration. Don't idle anymore than you absolutely have to.

[Crabby Mike]

I find that my ISL uses about a gallon of DEF every 300 miles or so, which works out to about a 40-to-1 fuel-to-DEF usage ratio, about what I'd been told to expect by Cummins. For me, that means I add one 2.5-gallon DEF container from Walmart for about every fillup (I usually fill around 800 miles). In practice, I keep several containers on board, and add a couple when my DEF tank drops to half or so per dash readout. I don't need to be more precise than that.

[darjacob]

I was told that the ISL 450 is considered a 2% motor, meaning that for every 100 gal of fuel you will use 2 gal DEF. The 600 commins is considered a 4% motor. Just what I was told...

[lwmcguire]

Originally Posted by darjacob

I was told that the ISL 450 is considered a 2% motor, meaning that for every 100 gal of fuel you will use 2 gal DEF. The 600 commins is considered a 4% motor. Just what I was told...

The 2% is very close to what my 450 uses