Hopper, Dump O/O's & Drivers

I thought it was crazy myself, until I topped the tanks at each end of a long deadhead a few weeks ago and verified it. It costs me about 1mpg to run deadhead compared to bobtail. The only thing I can figure is that with the width, height, and the fairings on the 780, the air is hitting the trailer about halfway down the tarp and body. Towing a 96" trailer, I have to lean to the driver window just to see the front half of the trailer. Hopefully I'll see the same figures with the 102" trailer I'm picking up next week - who knows on that one.

I'd also like to point out the difference in towing with the tarp open to blow the trailer clean. I saw nearly identical mileage between towing empty untarped, to loaded and tarped, and the boost gauge was showing about the same. That was at 60mph, and above 60mph it actually showed worse numbers and boost levels than loaded. After seeing that, I don't run more than 10 or 15 miles untarped no matter what the situation. Yesterday I ran down I-20 for about 2 hours with a truck pulling an untarped end dump at about 65mph - it was all I could do not to say something on the radio - but by the looks of his truck I'm pretty sure he would've just blown me off.

Running a hopper above 63mph starts hitting my mpg hard, it drops about .2mpg for every mph above it. The only thing I can figure is that with the tarp bows sticking out on top, and the hoppers hanging underneath (knock rails and all) it's about as aerodynamic as a porcupine.

I never realized how much wider a 780 was until I drove some narrow highways. The sidewalls of my drives stick out past the frame rails of the 96" trailer I'm under, and I'm pretty sure the truck is all of 102" wide at the fairings (someday I'll remember to put a tape measure in this truck). Fuel mileage comes down to low wind resistance, gearing and power - lack those anywhere and it costs you the bank.

The last thought on the strangely high fuel mileage empty is that at slight throttle openings the EGR system may not be operating at all. This hasn't been verified by anyone yet, I just don't know too many mechanics to ask about it.

 

That would be correct. We still have a few trucks that are in the local mix, but we don't depend on it anymore. Second that on the bottom feeders. They're pretty good at sniffing out a good niche and totally wrecking it. (Not to mention they're always the loudest complainers about how "there's no money in trucking")

 

I won't tear you up for your theory, because it's your operation, and you should run it how you see fit. Isn't that why you bought your own truck? So you didn't have to run it how somebody else wanted you to? Now, I will second WH's statement that it only seems doable *IF* you're actually getting the mileage deadheading that you say you are. (I'm not questioning you claims at all, please don't assume otherwise.) The mileage you're getting is better than I could get bobtailing, so your theory would never work for me...but my hauls are rarely over 300 miles to begin with; you and I are slaying two completely different dragons!

The bottom line is that if you're making money that is acceptable to you for the work you're putting in to accomplish it, whatever you're doing is the right thing to be doing.

 

2.79 yesterday in danville,had the mech. run the overhead and increase the timing on the 'ol b model earlier in the week,actually broke 6.25mpg's for the first time in my life,had to watch the temps though,it made 'er run a tad warm,hope everyone has a good and safe weekend

 

Hwy,i had a thought,maybe with all your crazy loads lately,and having to keep your tanks down so low for the way youv'e been being loaded,your truck is learning to run on just fumes

 

10-12 with an empty trailer seems reasonable with my Volvo if I keep it down around 65. Lower than that and I begin lugging the engine with 3.55's. Granted I have never verified it with a long deadhead at the pumps. Bobtail, it bumps up a couple more.

My truck averages about 6.5 with all of our short local hauls. Its does much better when it can stretch its legs on the road for a couple hundred miles. I am due for a Davco filter change, hoping it bumps up a tad when I get that done. But, who am I kidding I am nearly always hammer down on the fuel pedal lol.

Highside, whats your truck/trailer weigh empty? I don't think I saw what trailer you was pulling, but I did glance that beautiful Pete.

 

This CAT won't get anything near 10 empty or bobtail, maybe being dropped out an airplane door. But, mpg doesn't drop nearly as much loaded. Yesterday it did around 8 mpg DH'in but got caught in Atlanta Friday Night traffic. Winter was 5.5 average, not horrible with winter blend, idling, and all the mountains plus heavy footing it.

This trip 1st not winter blend and keeping my foot out of it was 1300+ miles at 7.2 mpg loaded to 79600 for all but 95 miles. Hope I don't continue to have the time to run 58 mph.

 

Put the heat on low and only use the floor vents,....

When it get to warm in the cab the snow melts and re-freezes on the windshield like in your pictures,....When it's really snowing heavy here in WI I turn the heat off altogether to avoid those problems,..

Something else that can help is heated windshield wiper blades,...There is a company in the UP of Michigan that makes them,..

 

Probably has something to do with the defroster turning the A/C on. I get the theory, with the A/C going it's blowing out dryer air, but it's winter anyway. The air is already dry. The rest I figure is just crappy design.