I have been running the 16 oz PS and 16 oz Nautilus 2-stroke oil. Milage gains is hard to prove but the engine definately runs quieter.
Best Milage ever 100% highway 19.35 miles/Gallon US
Average Milage 70 City/30 Highway 14.4 miles/Gallons US
I have been hand calculation mileage since purchasing truck.

 

Hey Cujo,

Nice looking truck in yer avatar, same color and make as mine. I appreciate all the replies, however... I know 2-cycle appears to be fine for pre '07 models. The '07 and newer models are designed to run on ultra low sulfur diesel. So, that is my question, does anybody know if it's ok to use the oil as an additive in '07 and newer models?

 

There no difference in the 07's with the 5.9, still the same motor, the 6.7 is where all the changes come in and then you have to look for fuel in some states in the south as they are still running LSD, and my cousins 6.7 sucked on the road only getting 16.4 MPG, but the overheads seem to be almost on the money, where ours make us feel good, dam right I'm getting 22 MPG in town, would my truck lie to me.

 

Actually Cummins made these engines able to run on ULSD long ago. ULSD has been in the works for years. The issue is the process of removing the extra sulfer, removes some of the lubrication properties (sulfer does not equal lubrication, its the process itself). The idea is adding 2 cycle oil replaces the lost lub. From what I have read 5.9's are fine with 2 cycle oil, the older ones with the VP44 benefits more than ours with the CP3. I would not run 2 cycle in an 07.5 with the 6.7. It's the 07.5's that will only run on ULSD. The 5.9's will run on damn near anything that you throw in the tank.

 

will 2 stroke make an 07 5.9 smoke

 

Shouldn't. No more than 1oz per gal mix.

 

make sure it is an ashless 2 stroke. if it isnt then it will burn crappy

 

One other thing you need to know about 2-cycle oil is that they don’t all have the same flash point. The flash points of 2-cycle oil can range between 120 and 380 degrees based on the info from the 2-cycle oil MSDS that I have read. Also I have found out by reading diesel fuel MSDS, is that they have lowered the flash point of diesel down from the normal 155+ range down to 125-130 degrees range and down to 100 degrees for winter fuel.

Also is the lower flash point a result of ULSD or a new may to make more $$ by refining/producing lower quality fuel? It also accrued to me with the lower flash point that diesel fuel has nowadays is that our PCM/ECM has code in it to help our engines run on the poor quality fuel they are selling to us, thus giving us lower fuel mileage?