[catpower400]

Seems like when I drive 65 I can get 19-21. When I drive 75, it drops to 16-18. Is this similar to what the rest of you have seen?

 

[setexan]

Yep, once I go over 70 mph my mileage goes down fast.

Over 70 17-18mpg
under 69 21mpg

 

[Tankercomm]

Heck once im over 65 it goes down quick for me. My economy sweet spot is right about 61 mph. I will get 19 to 21 at that speed but drop to 16 to 18 when going over 70.

 

[Iowa Farmboy]

At 60 MPH I get about 24.5 Mpg

At 69 MPH I get about 23 Mpg

But at 72 MPH I get about 20 Mpg

This is hand calculated but with minamal city driving just set the cruise on a two lane for 60 miles is my test strip. That's why I am leaning towards putting in a 6 Speed kit to get to lower RPM's when on the interstate.

 

[1911samcolt]

this is a great post for me to watch cause around her the highest speed i normally get to travel is like 60-65 and sunday i leave for a trip to Missouri to go fishing and have been wandering what kind of millage i will be getting BUMP

 

[catpower400]

bumpin the poll for the evening crew.......

 

[Tow Master]

Yup I see about a 2mpg diffence. I took my truck to florida once and got 18 on the way down. I was tired and in a hurry comming home doinf 80 most of the way. Got like 15 or something. I was jacked!

 

[Convoyduel]

My '05 F250 PSD, '06 Dodge Cummins and this '08 are all the same. Best overall mileage at roughly 65. Over 68, it drops considerably. All 3 trucks had/have a 4+mpg difference traveling at 65 versus 72.

 

[SDP-1]

i have what harley calles his interstate tune i make my best milage @ 82mph.

 

[oxeicher]

i have what harley calles his interstate tune i make my best milage @ 82mph.

I need one of those tunes!

 

[SDP-1]

it works good on i65 they pretty much dont mess with you under 87 plus.thats in alabama tho.