DEF forever?
Mountain Pass
Joined: Mar 2018
Posts: 176
Likes: 1
From: Syracuse NY
Def = diesel exhaust fluid for breaking down NOx (scr)
DPF = diesel particulate filter for catching diesel soot which is most of what you smell on pre-emissions diesels. Def & DPF are only similar in that they are diesel emissions controls and they are in no way dependent on one another. They are doing different jobs. The only thing I am not sure of is the correlation of active & passive regens on the production of NOx. Iirc more nox is created by higher egts which happens when passive or active regens take place and in turn you would then use more def during regens. We should really start a thread that asks def usage per say 5k miles. That would be interesting to know how people use more or less. I use about 5.75 gallons per 5k miles assuming that the dealer topped it off when I bought it new, which I doubt. I tow about 5% and drive it like a hot rod otherwise, unloaded. Case and point, my average mpg over 13k is 13.195.
DPF = diesel particulate filter for catching diesel soot which is most of what you smell on pre-emissions diesels. Def & DPF are only similar in that they are diesel emissions controls and they are in no way dependent on one another. They are doing different jobs. The only thing I am not sure of is the correlation of active & passive regens on the production of NOx. Iirc more nox is created by higher egts which happens when passive or active regens take place and in turn you would then use more def during regens. We should really start a thread that asks def usage per say 5k miles. That would be interesting to know how people use more or less. I use about 5.75 gallons per 5k miles assuming that the dealer topped it off when I bought it new, which I doubt. I tow about 5% and drive it like a hot rod otherwise, unloaded. Case and point, my average mpg over 13k is 13.195.
Fleet Owner
Joined: May 2015
Posts: 21,195
Likes: 306
From: Near Salmon Arm BC
Def = diesel exhaust fluid for breaking down NOx (scr)
DPF = diesel particulate filter for catching diesel soot which is most of what you smell on pre-emissions diesels. Def & DPF are only similar in that they are diesel emissions controls and they are in no way dependent on one another. They are doing different jobs. The only thing I am not sure of is the correlation of active & passive regens on the production of NOx. Iirc more nox is created by higher egts which happens when passive or active regens take place and in turn you would then use more def during regens. We should really start a thread that asks def usage per say 5k miles. That would be interesting to know how people use more or less. I use about 5.75 gallons per 5k miles assuming that the dealer topped it off when I bought it new, which I doubt. I tow about 5% and drive it like a hot rod otherwise, unloaded. Case and point, my average mpg over 13k is 13.195.
DPF = diesel particulate filter for catching diesel soot which is most of what you smell on pre-emissions diesels. Def & DPF are only similar in that they are diesel emissions controls and they are in no way dependent on one another. They are doing different jobs. The only thing I am not sure of is the correlation of active & passive regens on the production of NOx. Iirc more nox is created by higher egts which happens when passive or active regens take place and in turn you would then use more def during regens. We should really start a thread that asks def usage per say 5k miles. That would be interesting to know how people use more or less. I use about 5.75 gallons per 5k miles assuming that the dealer topped it off when I bought it new, which I doubt. I tow about 5% and drive it like a hot rod otherwise, unloaded. Case and point, my average mpg over 13k is 13.195.
In other words burn 100 gallons of diesel, they use 4.5 gallons of def.
And my diesel trucks get terrible fuel mileage, not good.
My old diesels pickups used to get better mpg than the new ones do.
There was a good article about 2 years ago on a semi truck site, tslked about the making and shipping, containers, parts on the actual trucks themselves etc. Where the team from a university studied the pollution it created to what it reduced.
Google it.
Logistics Pro
Joined: Apr 2017
Posts: 3,674
Likes: 51
From: SoCal
Its the first you’ve heard it, but I’m sure it will take off like most other internet folklore. DEF enables better fuel efficiency, more power, lower NOx emissions. Urea is manufactured on a scale of hundreds of millions of tons and it is needed in minuscule amounts in our DEF injection systems. I’d wager that more emissions are released by UPS trucks delivering amazon packages in one day than the entire DEF production and distribution process annually. And DEF keeps those UPS trucks clean 
Now I’m no tree hugger and I don’t care who deletes, but I’d rather base these conversations on facts.
Now I’m no tree hugger and I don’t care who deletes, but I’d rather base these conversations on facts.
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