8 mpg by driving 55

When I removed my speed governor and started runnin 68-70, my mpg increased significantly

 

Not worth it, unless you're driving somewhere that 55 is the limit, in which case I suggest you introduce your legislature to Mr Sammy Hagar and the 90s.

 

If you haul Flatbed no matter what you do you ll never get 8mpg we have a brand new Freightliner Cascadia the very best it has gotten is coasting downhill I got 7.6 but as soon as you shut down and idle for the night it will average 6 - 6.6.

 

If all one had to do was slow down to 55 from 65 to get 8 mpg instead of 6, everyone would be doing it. The reality is the 8 mpg truck at 55 will probably still get 7 and change at 65 or 70. The same as my square box of a truck may get about 6.0-6.25 at 65 range if I slow down to 55 I might get 6.5, 6.75.

Does it mean better mpg? Most of the time, yes. Is it such a swing in cost to really be worth it? Generally, no.

 

Yes,drive like theres an "eggshell" under the pedal...easy on throttle...you can still run...just slow to speed.I ve been averaging 8.2mpg running around 63mph.Get a slight run on hill,keep rpms around 1200. Another trick...find one of those gallon jugs of LUCAS and run a little every tank...keeps carbon down...helps fuel mileage..for $20 investment.JMO

 

Even silly stuff...like running at night with no traffic and "making the lights". The "start and stop" will wreak havoc on mileage.Even flatter alternate route (with extra highway changes will help.

 

Yes I can get 8. Cummins ISX 450HP / 10 SPD manual / 3.58 gears.

Mines spec'd for 55 to 60. 55 MPH is 1250 rpm. That's the max torque with the minimum HP.

Torque is what moves the truck.

I typically cruise in the low 60's. I stay around 1350 rpm to 1400.

That will get about 7.4

But going through the communist state at 58, I'll get 8+.

It's all about rpm's. And how hard the engine is working.

 

Lot's of people I talk to with new 18 or 19 trucks, with autos are getting almost 9 mpg.

8 is weak for them.