Selecting the correct RPM

[Catman8]

Hello JD owners, this is my first tractor I've owned with a hydrostatic transmission and need some advice. How do you know what is the correct RPM to select without wasting fuel or under powering the engine.



The gauge says rated 2500 RPM. does this mean that any time you are using a PTO implement that the RPM's have to be at 2500.

Let's say I have a full bucket of dirt and I am traveling along a flat paved road can I choose any RPM's I want, when do you know if your over revving the rpm's and wasting fuel or under revving the rpm's and putting a strain on the engine if there is such a thing. Thanks in advance.

 

[coldsteelva]

If you are using a 540RPM implement and your PTO is engaged, the PTO will be at 540RPM with your engine at the 2500 to 2600RPM mark. If you are not using the PTO, then you only need enough RPM to keep your load traveling at the speed you wish to travel.

Sort of like driving a manual trans car, you will know when the tractor is operating in the sweet spot. There will be less HST whine = less strain

 

[George2615]

For 540 PTO speed the RPM should be between 2500-2600. Most rotating attachments are designed to run at 540 RPM for best efficiency and operation. If your attachment works and works efficiently at lower RPM I don't see any harm in doing so. For example: I wouldn't run a post hole digger at full RPM, Just enough to get the job done.
HST is nice to control operating ground speed at whatever RPM you chose.
Newer tier 4 tractors usually require engines to be run at close to PTO speed. At higher RPM the exhaust temps are higher for better / faster regeneration. (At least that's what I have found).
When i am moving dirt, stone, snow or other loader work I run around 2200 RPM. Using the loader for lifting items I run the RPM slower.
Tier 4 engines do seem to be more fuel efficient.

 

[Catman8]

Thanks guys, yesterday I was pulling out fence post with my boom pole and I was throttling the RPM's around 2000 to lift with the three point, does the three point have the same lifting power at any RPM's.

When doing loader work I also felt that the 2000 to 2200 RPM range felt adequate for traveling and anything more felt like I was wasting fuel.

So is it safe to say that no harm can be done to the tractor or engine if your RPM's are to low.

 

[Millalien]

The only time I've found that RPM really matters is when running the PTO. Otherwise I'm usually at 1500 when I'm puttering around in no particular hurry and 2000 for plowing and aggressive loader work.

 

[motownbrowne]

Thanks guys, yesterday I was pulling out fence post with my boom pole and I was throttling the RPM's around 2000 to lift with the three point, does the three point have the same lifting power at any RPM's.

When doing loader work I also felt that the 2000 to 2200 RPM range felt adequate for traveling and anything more felt like I was wasting fuel.

So is it safe to say that no harm can be done to the tractor or engine if your RPM's are to low.

Diesel engines are fairly efficient at fuel delivery. They consume fuel based on the demand for power, not the RPMs you're running. What I mean is that if you're driving up a hill, for example, at 2000 RPM, versus 2500 RPM, and you're traveling at the same speed, the engine will use almost the same amount of fuel, because the same amount of "work" is being done. Now there is some extra friction, so you will use a little more, but not much.

Personally, if my tractor is doing "work" I'm over 2000 RPM. Only reason it's ever less is if I'm doing very precision work with the loader, or backing up to an implement. Lowering the RPMs seems to help me focus a little better and makes the hydraulic response a little slower. If I'm working the tractor hard, I'm at PTO RPM, which is almost wide open throttle (WOT) on my machine. Tractors are designed to be run at PTO RPM to achieve work. That's where they are the most efficient. I don't think you'll harm the machine by running it under PTO RPM, but i personally don't putz around at 1500 RPM, unless I'm just moving the tractor or a light trailer around.

Also, I could be mistaken, but i think that the three point will lift the same amount at any RPM, you just have more flow, and faster response at higher RPMs.

 

[4570Man]

Your lift will be slightly stronger and way faster at a high rpm. Experience is the best gauge for most things including rpm. You'll get the hang of it.

 

[Luke'sScreenName]

Your lift will be slightly stronger and way faster at a high rpm. Experience is the best gauge for most things including rpm. You'll get the hang of it.

X2...

 

[Catman8]

Thank you for your posts everyone, very informative and helpful.

 

[jenkinsph]

With the 2032R I would not be concerned about fuel consumption. You could waste fuel or try to conserve fuel while doing the same tasks for a days work and could not buy a candy bar for the savings difference imo. Five gallons of fuel can get a lot of work done. I would avoid long idling times though, better to shut the tractor off.

Tasks such as mowing, tilling and snow blowing I prefer pto rated speeds. Box Blading, raking and loader work are at various speeds that feel appropriate to me. YRMV.