New emissions standards for diesel engines have ushered in a whole new way of calculating fuel efficiency. Now tractors are judged by not only the “fuel” they consume, but also the “fluid” required to get emissions down to near-zero levels as required by the EPA’s Tier 4 emissions standards. It’s no small task, as tractor manufacturers have had to devote a large portion of their R&D dollars over the last decade to design engines that don’t smoke.

DOWNLOAD THE FUEL EFFICIENCY RATINGS FOR HIGH-HP 4WD/TRACK TRACTORS HERE (PDF).

DOWNLOAD THE FLUID EFFICIENCY RATINGS FOR HIGH-HP ROW CROP TRACTORS HERE (PDF).

Tractor manufacturers have adopted one of two foundational technologies to date to meet the mandated cuts in particulate matter and oxides of nitrogen by the interim deadline of January 2011. One, called Selective Catalytic Reduction, or SCR, requires the use of an engine after-treatment called diesel exhaust fluid, or DEF, which is sprayed into the exhaust at a rate of 3% to 6% of fuel used, depending on load and operating conditions. Challenger, Case IH, Fendt, Massey Ferguson and New Holland use this strategy.

The other strategy, called Exhaust Gas Recirculation, or EGR, used by John Deere and Versatile, recirculates the exhaust gas before it leaves the engine to reduce nitrous oxides in the emissions. A diesel particulate filter is used to trap the soot. This regeneration cycle requires extra fuel, which the lab estimates is less than 1% of the total fuel consumed based on the fuel used during forced regenerations at three different load levels, as measured during the time of testing.

The big question now is, “How do these new tractors perform fuel-, or more accurately, fluid-wise?” Farm Industry News addressed that question using data from reports published by the Nebraska Tractor Test Lab, or NTTL, the officially designated tractor testing station for the U.S.

The lab had to revise its evaluation procedures in the past few years to account for the added fuel and DEF used in the tractors.

This report takes those fluids into account, and gives you the fluid efficiency ratings of the high-horsepower, or HHP, tractors (150 hp and up) that have been officially tested in the last five years, from 2009 to 2013.

Please note that only those models that have been tested are included in this report. So, if you don’t see a particular model in the lineup, it means it hasn’t been tested yet.

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Also, please note that both Tier 3 and Tier 4 interim tractors are included. Testing of Tier 4b engines will begin this spring, according to the NTTL.

As for Tier 4 interim tractors being better or worse on fuel, NTTL Director Roger Hoy says, “I really cannot make a general statement, except to say that DEF and fuel consumed during regenerations need to be considered along with fuel economy.”

We’ve divided the tractors into two categories based on chassis: row-crop tractors and HHP four-wheel drives. Ratings for the 4-wd tractors are published here:

DOWNLOAD THE FUEL EFFICIENCY RATINGS FOR HIGH-HP 4WD/TRACK TRACTORS HERE (PDF).

DOWNLOAD THE FLUID EFFICIENCY RATINGS FOR HIGH-HP ROW CROP TRACTORS HERE (PDF).

Fluid-efficiency ratings for both groups ranged from 11 to 15 hp-hr./gal. As with fuel efficiency in cars, the higher the number, the better a tractor is on fuel or “fluid” economy. You must determine whether the fuel savings will ultimately justify a trade-in.

— Scott Grau, research manager at Penton Media, contributed to this report.