Farm Progress

Shift up, throttle back

Mark Moore 1

November 1, 2008

4 Min Read

You've Heard all the usual tactics for using less tractor fuel: Change the oil, clean the air filters, inflate the tires. But there's one operating procedure that can significantly reduce fuel costs, without spending a dime. It's a simple matter of watching how you operate your tractor: Shift up and throttle back.

The practice involves reducing engine speed 70 to 80% of rated engine speed and shifting to a faster gear to maintain the desired field speed and implement productivity.

“Tractors are normally a little oversized for the implement they are using,” says Roger Hoy, director of the Nebraska Tractor Test Lab. “Rather than run at full throttle, shift a gear or two up and reduce the throttle. That action alone will bring some significant fuel savings.”

That's the idea behind the newer infinitely variable transmissions (IVTs) and continuously variable transmissions (CVTs). “Research done at the Nebraska Tractor Test Lab indicates that there can be up to a 40% fuel savings,” Hoy says.

The beauty of this tactic is that it can be used with any activity, although fuel savings will vary depending on the task. “Realistically, someone could expect a 10 to 15% savings by religiously following the shift up, throttle back tactic,” Hoy says. “If you are doing something that requires the power, you may not see as much of a savings. But when you are running at a higher rpm and don't need the power for the job, you're just wasting fuel.”

The bottom line is operating the engine at its lowest speed with the power to do the job. That's when fuel efficiency is the highest.

Robert Grisso, extension engineer at Virginia Tech, says the shift up, throttle back (or gear up and throttle down) action is typically used on light load operations, or those that require less than 65% of full engine power. Guidelines say to stay within the engine rpm working range specified in the operator's manual; select a faster gear to maintain travel speed and implement productivity while reducing engine rpm; and don't overload the engine.

Consider the task

Experts agree that producers may not always think about fuel efficiency while going about day-to-day operations, but considering the task at hand before sending a tractor out in the field can also save on diesel.

“If you have multiple tractors available, don't use a tractor bigger than necessary,” Hoy says. “If I had a 250-hp and a 180-hp tractor available, I'd be putting as much time as I could into the 180-hp tractor, simply because on average it will use less fuel. Save the larger tractor for the jobs where its power is really needed.

“The 220-hp might pull slightly faster,” he continues. “But is an extra quarter mile an hour worth it to your operation versus how much fuel you will use?”

However, a larger tractor sized properly for a light load may use the same amount or less fuel as a tractor half the size operating at full load. “Specific fuel consumption can vary widely for individual tractor models,” Grisso says. “Keep accurate records of the fuel usage of all tractors under a variety of operating conditions. With accurate records, you can select the most economical tractor for a specific operation.” The University of Nebraska Tractor Test Lab reports are a useful resource when making an efficiency selection, he adds. (See “The Most Fuel-efficient Tractors,” page 21.)

New equipment

Newer tractors are also, on average, more fuel efficient. More efficient engines and better transmissions, including the newer IVTs (John Deere) and CVTs (AGCO), take the guesswork out of operating machinery at the right speed and rpm. “Newer transmissions clearly give a big fuel savings,” Hoy says.

Another new technology that can be a big fuel saver is GPS autosteering. “The GPS systems reduce the time in the field; you're not going over the same ground twice,” Hoy explains. “Not only are you saving time to do the task, but our studies show that you can reduce fuel consumption by 5 to 10% as well.”

If you're in the process of purchasing a newer tractor, Hoy says the Nebraska Tractor Test Lab reports indicate a tractor's fuel use based on drawbar performance. The reports also include information on PTO performance and fuel data. “PTO performance is more closely related to engine performance and will provide additional information to help compare tractors,” Hoy says. “While we conduct drawbar testing officially between 40° and 80°, the PTO air temperature is more tightly controlled, allowing even better tractor-to-tractor comparisons.”

Producers can take many actions to save fuel. “But the practice that will show the most meaningful and most immediate fuel reduction is shifting up and throttling back,” Hoy says. “And that practice doesn't involve purchasing a new tractor.”

About the Author(s)

Mark Moore 1

Mark Moore is an agricultural writer/photographer based in southeast Wisconsin. Mark’s professional career includes work in seed, crop chemicals, row crops, machinery, fruits and vegetables, dairy, and livestock.

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