Fuel Sipper
 

Can someone explain more about Fuel Sipper:

"good for stop-and-go traffic; not designed for highway driving"

What's "not" about highway driving with it? How will mileage compare to say the 80DD on the highway? What is the best for highway driving if it's not fuel sipper, and why?

Also, when I ordered, there was just "Fuel Sipper" now there seems to be "Fuel Sipper 65hp" and "Fuel Sipper 80hp" - which do I have if I have the older "Fuel Sipper"?

7.3 Diesel

The deal with the FS program that makes it better for in-town driving is the stock-ish low boost fueling and the early upshifts. For all intents and purposes, there are relatively few fueling and injection timing differences between it and a daily driver or performance tune at a cruise speed/load condition. You should not notice much of a difference in economy between an 80HP DD tune or Fuel Sipper if you're cruising down the highway all the time.

I think that covers the first two questions.

Lastly, I think that the originally-offered Fuel Sipper was an 80-ish HP program and the 65 HP came out later.

Thanks for the reply.

The "not designed for highway driving" just made is sound like you shouldn't drive on the highway with it. You are saying it would be fine for highway, and nearly identical to any other 80hp tune. I think it's probably the program I'll set to when I let my wife drive the truck...

Yeah. It's definitely not going to hurt anything to "drive" with it. It actually drives really well once the oil temperature gets warm. There are a few minor changes between it and the DD tunes, but MOSTLY the low boost fueling rates and shift points.