Fuel Mileage Per Gallon

The last truck I drove before I quit in 2000 was a Kenworth T2000. It easily averaged 6.5 mpg with mostly 70-80k gross weights. It was governed at 68 mph and I only idled when temps were too low or too high.

Specs:
Cummins N14+ 435 hp/1450 lb-ft
Eaton RT-14710 10 speed direct
2.85 rear end
516 rev/mile 22.5 lo pro tires.
Approx RPM at 68 mph: 1667 rpm.

 

http://www.thetruckersreport.com/tr...n-wheelers/7773-fuel-mileage-whats-yours.html

Here's a link I started a while back that has some discussion regardging MPG's. Hope it helps!

 

I run each back and forth from Georgia to western Wisconsin, and am averaging 7.0 at the moment. I drive a 2006 Freightliner Columbia with a 470 Detroit, and have an APU (Alternative Power unit w/heat and air conditioning) installed to eliminate the need for engine idling. Prior to the installation of the APU, I was averaging 6.7 mpg.

 

i drive a freightliner columbia condo, 455 detroit diesel, automatated shift, and generally my loads are under 20,000 pounds. sometimes i get 5.3 miles, sometimes i get 6.2 miles. i am in some of the hills of PA, and at times at a stand still in Connecticut "stand still" rush hour traffic. i only idle my truck for about 4 hours each day, this is for a nap with the a/c on, while i am waiting in PA.

 

I've got a 2006 Mack, 380/410 hp, 10 speed. Running the midwest, pulling standard loads of 50,000 in a pneumatic trailer I am getting right at 5.7 mpg. I limit idling, haven't idled at night since about 3 weeks ago when the heat wave ended, but do all my unloading at about 950 rpm 2-3 hours per day. Trailers are pretty bad aerodynamics, previous truck showed a clear 1 to 1.25 mpg increase when hooked to a van. So I am driving in a manner that would bring right at 7 mpg if it were a different style trailer.

 

I had not realized that pneumatics were not as aerodynamic as a van.

 

Despite being generally rounded, they have vertical and horizontal ribbing on the trailers, hoses, and valves on the side out in the airstream, catwalks on top, ladders on the rear and hatches up on top in the airstream. All of those disturb the passage of the air as it flows past the trailer, creating turbulence that takes energy (fuel) to overcome. Additionallly, I have four large hoppers down in the lower airflow under the trailer as well as plumbing down there to cause turbulence

On a van, once the air gets onto the top and down the sides, its a straight smooth flow until it hits the rear. at the rear, they have a low pressure zone that forms in the immediate wake of the trailer and it pulls some of the air back in what is called a "burble", which is why you see car haulers like Luvmyhubbys' other half using the tail cones on their trailers. Those manage the flo of air and prevent the low pressure burble from forming. That low pressure zone basically acts like it is pulling the trailer backwards, and takes power to overcome.

Of course, a rough sided van, with exterior posts or a container with corriugated sides don't do quite as well as a smooth side van does either.

I don't pull a van much, but when I have the fuel mileage jumps quite a bit, and my numbers go up. And I am pulling vans without an airshield on top, or cab extenders, which would help some more. But, there's good money in pneumatics, and even when I buy my own truck I know that I won't get quite the mileage that the truck is capable of. Just something to live with.

 

I'm very impressed. Air flow and aerodynamics is not one of my better subjects, and it's obvious that you've brushed up on the subject much like all the others you wade in on....

 

There are times that the twenty years of playing around with aircraft and stock car racing does come in handy. Airflow is airflow, regardless of what it is passing.