9 Diesel Engine Fuel Saver Tips for Tractor-Trailers

branhamdiesel By branhamdiesel, 16th Jan 2011 | Follow this author | RSS Feed | Short URL http://nut.bz/rzr7ha.c/
Posted in Wikinut>Guides>Transport>Cars

Basic things often overlooked when dealing with a loss of fuel mileage in regards to tractor trailers.

9 Diesel Engine Fuel Saver Tips for Tractor-Trailers

There are many fringe science devices out there that claim bolt on fuel economy. In my experience, there are a multitude of reasons for poor fuel economy that are overlooked by owner-operators and fleet managers. I don’t believe in bolt on fuel economy, but I do know a lot of things that can cause poor fuel economy.

Tire Pressure - I know it doesn’t seem like a big deal, but instead of just thumping your tires, check the pressure. The drag of even 1 or 2 low tires causes enormous amounts of friction your engine has to overcome to get you up to speed and then maintain that speed. I have seen low steer tires rob an engine of ½ mile per gallon.

Tire size - Many times I see Trucks with 24 talls towing a van trailer with 22 low pros. Its basic drag friction here. The top of the trailer is now higher than the back of the trailer. This cause the front of the trailer to stick up above the air foils wind stream. Excess air turbulence is created, robbing you of fuel mileage.

Gear Ratios - Know the speed you want to maintain. An off road dump truck and an on highway dump truck should not be setup the same. Your top transmission ratio, rear end ratio and tire size all determine optimal cruising speed and top speed. Before you buy a truck, check these. Tires are easy to change out, but a transmission and rear end ratio changes need major surgery. If you aren’t sure what need talk to an experienced tech a dealership or reputable shop. Most On Highway applications are setup for optimal cruising speeds of 65mph for best fuel economy.

Slow down - As stated above, optimal cruising speeds for most on high trucks is 65mph. Every mph over 65 you are loosing fuel economy. Rough estimates are about ¾ to 1 mpg lost at 75mpg.

Torque band - Stay in it when shifting up. 1200 - 1500 rpm is standard but check you mfg recommendations to be sure. Too many times I have seen cowboys that rev limit the engine to shift. Basically, you just made a lot of noise that cost you more fuel than needed, and it is hard on your engine.

Trailer to Tractor Spacing - Most drivers know where they want the fifth wheel set to change the weight on the axles to compensate for the load they are hauling. Most people have no idea what kind of air gap to have between the most rear point of the side fins and the front of the trailer. 18” - 20” is optimal. This creates an air bubble between your tractor and trailer that helps keeps the air flowing smoothly from the tractor over the trailer.

Overhead Adjustment - Your valve, injector and engine brake adjustments tighten and loosen overtime. Use your engine mfg recommendations for intervals, but get it done. This not only helps keep your fuel mileage at par, but extends the life of your engine.

ECM programmable parameters - A common thing overlooked is the transmission configuration screen. Often the tire size on a truck is changed to a taller or shorter tire. When the original tire configuration is changed on an electronic engine, the parameter must be changed as well. If not, you will be going faster or slower than the speedometer is actually reading, as well as your odometer. Your log book will be off, not to mention your pen and paper fuel mileage calculations.

Trip Reports - If you are a Fleet operator or owner operator, go to the shop you frequent and have them pull your trip reports often. They will charge you a minimal fee if anything to print these reports. These reports must be pulled from the ecm, and must have an oem program to do so. The data is invaluable. Your get detailed information on idle time percentage, cruise time percentage, top speed percentage, as well as the ecm calculated fuel mileage. This report can help your troubleshoot your driver’s or your own driving habits that need attention.


Bolt On Fuel Economy, Dealership, Diesel, Engine, Fleet Managers, Fuel, Fuel Saving, Overhead, Overlooked, Ratios, Save, Semi, Shops, Technicians, Tires, Tractor, Truck

Meet the author

author avatar branhamdiesel
I am diesel repair shop owner. I have spent nearly every moment since I was a teenager in a shop. I have worked for multiple dealerships includiing Cat, Freightliner and International. I have held positions at those dealerships of technician, fore...(more)

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author avatar Retired
17th Jan 2011 (#)

Thanks for sharing

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author avatar Retired
18th Jan 2011 (#)

You have written an outstanding guide here. Thanks for sharing.

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author avatar Denise O
25th Feb 2011 (#)

Wonderful suggestions to help save in fuel usage. Nice read.
Thank you for sharing.:)

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author avatar Serge
6th May 2015 (#)

It's true that tire pressure can get skipped over easily. Flat tires really do decrease gas mileage considerably. It can be tempting to go eighty miles per hour, but it really is more efficient to slow down. Driving a tractor trailer can be a pretty big learning curve. Thanks for the tips!
<a href='http://www.brockmantrailers.com/commercial-trailers/' > www.brockmantrailers.com</a>

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