I have been doing some informal research in my book about the Nebraska Tractor Tests. In 1919, the state of Nebraska passed a law that any tractor sold in the state had to undergo a series of performance tests at the University of Nebraska. The test information was to be publicly available.
My book covers 1,551 different tractor tests from 1920-1984. Many foriegn as well as domestic models were tested. All went through a standard series of testing, incuding drawbar, PTO dyno tests, etc. Fuel economy was noted also and was tallied in Horsepower Hours per Gallon of fuel.
As would be expected, there was a very wide range of fuel economy numbers. I was a bit surprised to see the relatively poor fuel economy of propane.
Here is a very brief summary. This is by no means all-inclusive as there is a huge amount of data. I will list the lowest economy numbers and the highest of each fuel type.
Horsepower Hours per Gallon:
Diesel- 9.29- 18.64
Gasoline- 3.30- 13.18
Propane- 7.26- 9.99
Distillate- 6.71-12.44
Kerosene 4.85-11.36
Diesel fuel really is the way to go for most power out of the resource. I looked closer at the top 30 tractors in the diesel category. 22 were naturally aspirated, 8 had turbos. Of the 22 na machines, 16 were imported models, 5 of the US made were John Deere two-cylinder engines.
Deutz had a full 7 models, those are air-cooled engines!
The mighty John Deere Model 720 two-cylinder set a record for fuel economy in 1956, this record was not broken until 1983 when a Yanmar built John Deere turbocharged tractor finally topped the 18 Horsepower Hours per Gallon barrier. It was the only machine to beat the 720.
I found it interesting that so many foriegn models rated so well in economy. Reckon when fuel costs more it pays to make engines more efficient.
Gasoline actually fared pretty well overall, and distillate did better than I expected, much better than propane. No propane engine achieved 10 horsepower hours per gallon.
All of these numbers were recorded at maximum power at rated speed. Fuel economy almost always dropped at lower power settings, but there were a few exceptions.
Several tractors were tested in different fuel configurations. These machines were virtually identical except for the necessary changes to accomodate the different fuels. Distillate engines always made less power per cubic inch, but the fuel economy remained comparable. Surprising to me was the fact that gasoline, propane, and diesel versions of the same displacement made almost identical power with the BMEP being within a couple of percent.
Most of the BMEP numbers are under 100 psi at maximum power at rated speed. When they are lugged down, BMEP went up, some dramatically, but generally it seems that if engines are going to live long lives they had best keep the BMEP around 100 or so. I wonder what modern engines put out on a long term basis.
These tractor engines were all tested on a dyno at 100% power for several runs up to two hours, plus did drawbar testing. One drawbar test was for ten hours non-stop at rated power. Try that with your SBC.
I'm not sure what to make of all this, I found it interesting.
Comments, anyone?
Joe
My book covers 1,551 different tractor tests from 1920-1984. Many foriegn as well as domestic models were tested. All went through a standard series of testing, incuding drawbar, PTO dyno tests, etc. Fuel economy was noted also and was tallied in Horsepower Hours per Gallon of fuel.
As would be expected, there was a very wide range of fuel economy numbers. I was a bit surprised to see the relatively poor fuel economy of propane.
Here is a very brief summary. This is by no means all-inclusive as there is a huge amount of data. I will list the lowest economy numbers and the highest of each fuel type.
Horsepower Hours per Gallon:
Diesel- 9.29- 18.64
Gasoline- 3.30- 13.18
Propane- 7.26- 9.99
Distillate- 6.71-12.44
Kerosene 4.85-11.36
Diesel fuel really is the way to go for most power out of the resource. I looked closer at the top 30 tractors in the diesel category. 22 were naturally aspirated, 8 had turbos. Of the 22 na machines, 16 were imported models, 5 of the US made were John Deere two-cylinder engines.
Deutz had a full 7 models, those are air-cooled engines!
The mighty John Deere Model 720 two-cylinder set a record for fuel economy in 1956, this record was not broken until 1983 when a Yanmar built John Deere turbocharged tractor finally topped the 18 Horsepower Hours per Gallon barrier. It was the only machine to beat the 720.
I found it interesting that so many foriegn models rated so well in economy. Reckon when fuel costs more it pays to make engines more efficient.
Gasoline actually fared pretty well overall, and distillate did better than I expected, much better than propane. No propane engine achieved 10 horsepower hours per gallon.
All of these numbers were recorded at maximum power at rated speed. Fuel economy almost always dropped at lower power settings, but there were a few exceptions.
Several tractors were tested in different fuel configurations. These machines were virtually identical except for the necessary changes to accomodate the different fuels. Distillate engines always made less power per cubic inch, but the fuel economy remained comparable. Surprising to me was the fact that gasoline, propane, and diesel versions of the same displacement made almost identical power with the BMEP being within a couple of percent.
Most of the BMEP numbers are under 100 psi at maximum power at rated speed. When they are lugged down, BMEP went up, some dramatically, but generally it seems that if engines are going to live long lives they had best keep the BMEP around 100 or so. I wonder what modern engines put out on a long term basis.
These tractor engines were all tested on a dyno at 100% power for several runs up to two hours, plus did drawbar testing. One drawbar test was for ten hours non-stop at rated power. Try that with your SBC.
I'm not sure what to make of all this, I found it interesting.
Comments, anyone?
Joe
