Any guesses on Gal/Hr for 3520-3720 and the 4000 20's?

[tuolumne]

I can offer a guess at 50% - 75% load...my 3520 has 46 hours on the meter and I've put 15 gallons into it. The gauge currently reads a little over 3/4 full, so call that 18 total gallons. That is .4 gallons/hour. To guess at what those hours were...
- 10 hours on the backhoe at 2000 rpm
- 13 hours doing loader work or moving logs at 1500 rpm (I leave the throttle set around there and use the foot throttle occasionally for a little more oomph)
- 3 hours?? idle time while thinking, greasing, switching implements etc.
-20 hours using the chipper at 2500 rpm (avg. I was running it at about 2300 for a while when new, and now run it at 2600)
This is a relatively small displacement engine, and just sips fuel. Occasionally I'll hear the turbo whine when a large log goes through the chipper, or when climbing the steep hills on our property. It is nice to know I can get a full days work out of a five gallon gas can. The 2.7 gph listed at PTO RPMs sounds a bit high to me.

 

[nmu98]

I can offer a guess at 50% - 75% load...my 3520 has 46 hours on the meter and I've put 15 gallons into it. The gauge currently reads a little over 3/4 full, so call that 18 total gallons. That is .4 gallons/hour. To guess at what those hours were...
- 10 hours on the backhoe at 2000 rpm
- 13 hours doing loader work or moving logs at 1500 rpm (I leave the throttle set around there and use the foot throttle occasionally for a little more oomph)
- 3 hours?? idle time while thinking, greasing, switching implements etc.
-20 hours using the chipper at 2500 rpm (avg. I was running it at about 2300 for a while when new, and now run it at 2600)
This is a relatively small displacement engine, and just sips fuel. Occasionally I'll hear the turbo whine when a large log goes through the chipper, or when climbing the steep hills on our property. It is nice to know I can get a full days work out of a five gallon gas can. The 2.7 gph listed at PTO RPMs sounds a bit high to me.

I dont think your using the tracktor ar 50 to 75% load... Your usiung it at 50 to 75% of full operating throttle.... You can run your rpms at full throttle and have very little load on the engine... Load is the amount of "work" the engine is doing.

BTW, I have put as much fuel in my 3720 in the last 25 hours as you have in the time you have owned it...... Your doing well...

 

[tuolumne]

You're correct, the engine has not been under significant load during all of these hours. I am sure that a task like heavy mowing would be using more fuel.

 

[Z-Michigan]

I'd think fuel consumption ought to directly prorate with hp on a tractor.

There are actually very large differences between tractors in terms of the fuel used per hp-hour. The NE tractor tests provide this figure. Very efficient tractors may burn .4 lb per hp/hr while many common but less efficient models burn .5 to .55, and some go over .6. All this is for rated RPM and rated hp; the test results I've seen show that max power is typically a fraction more efficient than rated rpm (maybe by 1-2%) and lower power levels are usually dramatically less efficient.

The good news for JD owners is that from reading bunches of the NE tractor test reports, JDs are often among the best in fuel efficiency, sometimes by a large margin. Fewer cylinders and larger displacement usually go along with better efficiency. Turbo or non-turbo doesn't seem to correlate either good or bad.

 

[AKfish]

Z- thanks for the link to the Nebraska testing site. Great info! (Did note that your 5105 is just slightly more efficient than the 4320...)

Nonetheless, maybe you can shed some light on the tables --- I just could not understand the "Varying Power and Fuel Consumption" table for the life of me!!

It listed the Max Hp and Operating RPM at the top of the table example; 4320 = 41.58hp @ 2399 RPM and then it went all the way down to 0.85hp @ 2649 RPM.

That is just bass ackwards to my pea brain! I realize that at some level of RPM's the HP begins to plateau and actually drops off --- but not to the extent that the table illustrates!

Don't get it ---

Thanks again.

AKfish

 

[Z-Michigan]

I believe that the varying power chart represents fuel consumption at the engine's "high idle" where you are running high rpm's under moderate to almost no load. I'm not sure I find it very useful, but that's what it is. Most of us of course will be running much lower rpm's at lower load, or at the most will be running the rated speed for 540 PTO rpm.

I chose my 5105 in part because of the efficiency indicated in their tests. Based on my experience and reading other people's fuel use here and on the NH forums, I think the test is a good guide.