WOT on diesel tractors

[Scooby074]

Yes I do run my car at full throttle when I have the loader attached to it so I get max cycling rates when I'm tryin to get a truck loaded faster. I know what everything means on the machine. Was asking a question on others reasoning. No need for anyone to get funny. So the census seems to be to save fuel. Fair enough

Fuel may be a part of it, but I think to many users on here the noise weighs in. Frankly I think some are "scared" of the noise their tractor makes at full throttle. Not just the volume for their hearing, but they think "that doesnt sound right, and must be putting way more wear on the engine!!!" and throttle down as a result.

 

[ddivinia]

If I am doing a bunch of loading I will run lower than full and use the foot throttle when I need more hydraulic pressure.

D.

 

[Tx Jim]

I agree on running lower rpm's while loading/unloading hay while utilizing foot throttle to spped engiine up when required. Anyone that thinks lower rpm's isn't saving fuel is only fooling themselves.

 

[PapaPerk]

Because good operators know when to use full power and when not too.... That's why tractors are equipped with throttles.

 

[Sysop]

Because good operators know when to use full power and when not too.... That's why tractors are equipped with throttles.

+1 :thumbsup:

 

[TripleR]

Because good operators know when to use full power and when not too.... That's why tractors are equipped with throttles.

+2 :thumbsup:

I grew up using tractor on which the tach often didn't even work.

 

[JDTank]

For tractors with hydrostatic transmission, the pumps are designed VERY SPECIFICALLY to run at their rated RPM input speed, which is full throttle.

I don't know how many times I have to type this out on these forums. Hydro pumps on smaller machines have multiple pistons inside of them. If you work your tractor at less than full RPM, the load of pressurizing the oil is not distributed equally across all of the pistons inside the pump. This creates excessive heat and is hard on the seals on the pistons, since the load is not distributed across all pistons equally. This isn't rocket science. Hydrostatic tractors are designed to be run at full RPM. If your just moving the machine, or driving around, 3/4 throttle is ok. If your doing any kind of work, and you aren't running at full throttle, you shouldn't own a tractor. Why buy something to use it the wrong way?

Tractors with gear transmissions and a controllable throttle are a different story, to some degree. While the drive-train is not controlled with hydro fluid, your hydraulic pump powering your loader, power steering, 3 pt arms, all of that stuff, is still suffering the same fate. The higher the RPM, the easier it is for your pump(s) to do their job. In turn, they will last longer.

Fuel economy in a diesel engine is more dependent on load, than RPMs. I wouldn't let that be a determining factor in your choice to run at certain RPM's. Why spend a minimum of $10,000 to get into a diesel tractor, and than gripe about buying $40 worth of fuel? You think your saving money on fuel, if you are, it is pennies worth, but you forget you are decreasing your hydro pump life. In the end, that will cost you money too.

The old myth about diesel engines running at high RPM's being bad for them is long gone. People forget that engines today, especially diesels, are built to tolerance levels greater than ever before. Machining is extremely refined, oil lubricating qualities have never been higher. Even the small Yanmar engines like the one in my X740, running at 3,600 RPM, can easily handle it. That actually isn't a high RPM at all. I have seen diesel engines go much higher, and last just as long as low RPM diesels. With the small displacements we are dealing with, you will see high RPM's. Get into larger displacements, max RPM's drop. Large locomotive engines reach full RPM at about 950 RPM, that's it. However, they are also 16 cylinder engines, with each cylinder having a displacement bigger than that of an entire diesel engine in an HD pickup truck.

 

[arlen4720]

For tractors with hydrostatic transmission, the pumps are designed VERY SPECIFICALLY to run at their rated RPM input speed, which is full throttle.

That is a load of ****. I think what you are saying is that hydrostatic transmissions require sufficient "charge" pressure and flow to operate properly. That sures the **** ain't full throttle.
Run the RPM's up to the point the tranny is not "sqawling" and you have enough charge pressure.

Tractors with gear transmissions and a controllable throttle are a different story, to some degree. While the drive-train is not controlled with hydro fluid, your hydraulic pump powering your loader, power steering, 3 pt arms, all of that stuff, is still suffering the same fate. The higher the RPM, the easier it is for your pump(s) to do their job. In turn, they will last longer.

The gear pumps don't care about the RPM, they just move so much oil per rev. What isn't used bypasses back to tank. More RPM's are more wear not less.

Don't get me wrong...there is nothing "wrong" with runnig at full throttle, I'm just saying use the amount of power and RPM's you need for the job at hand.

 

[rider0]

For tractors with hydrostatic transmission, the pumps are designed VERY SPECIFICALLY to run at their rated RPM input speed, which is full throttle.

I don't know how many times I have to type this out on these forums. Hydro pumps on smaller machines have multiple pistons inside of them. If you work your tractor at less than full RPM, the load of pressurizing the oil is not distributed equally across all of the pistons inside the pump. This creates excessive heat and is hard on the seals on the pistons, since the load is not distributed across all pistons equally. This isn't rocket science. Hydrostatic tractors are designed to be run at full RPM. If your just moving the machine, or driving around, 3/4 throttle is ok. If your doing any kind of work, and you aren't running at full throttle, you shouldn't own a tractor. Why buy something to use it the wrong way?.

So manufacturers install throttle levers and linkages for the sole purpose of evoking nostalgia?

 

[GManBart]

For tractors with hydrostatic transmission, the pumps are designed VERY SPECIFICALLY to run at their rated RPM input speed, which is full throttle.

I don't know how many times I have to type this out on these forums. Hydro pumps on smaller machines have multiple pistons inside of them. If you work your tractor at less than full RPM, the load of pressurizing the oil is not distributed equally across all of the pistons inside the pump. This creates excessive heat and is hard on the seals on the pistons, since the load is not distributed across all pistons equally. This isn't rocket science. Hydrostatic tractors are designed to be run at full RPM. If your just moving the machine, or driving around, 3/4 throttle is ok. If your doing any kind of work, and you aren't running at full throttle, you shouldn't own a tractor. Why buy something to use it the wrong way? If you make a statement like this, you probably shouldn't own a tractor.

Tractors with gear transmissions and a controllable throttle are a different story, to some degree. While the drive-train is not controlled with hydro fluid, your hydraulic pump powering your loader, power steering, 3 pt arms, all of that stuff, is still suffering the same fate. The higher the RPM, the easier it is for your pump(s) to do their job. In turn, they will last longer.

Fuel economy in a diesel engine is more dependent on load, than RPMs. I wouldn't let that be a determining factor in your choice to run at certain RPM's. Why spend a minimum of $10,000 to get into a diesel tractor, and than gripe about buying $40 worth of fuel? You think your saving money on fuel, if you are, it is pennies worth, but you forget you are decreasing your hydro pump life. In the end, that will cost you money too.

The old myth about diesel engines running at high RPM's being bad for them is long gone. People forget that engines today, especially diesels, are built to tolerance levels greater than ever before. Machining is extremely refined, oil lubricating qualities have never been higher. Even the small Yanmar engines like the one in my X740, running at 3,600 RPM, can easily handle it. That actually isn't a high RPM at all. I have seen diesel engines go much higher, and last just as long as low RPM diesels. With the small displacements we are dealing with, you will see high RPM's. Get into larger displacements, max RPM's drop. Large locomotive engines reach full RPM at about 950 RPM, that's it. However, they are also 16 cylinder engines, with each cylinder having a displacement bigger than that of an entire diesel engine in an HD pickup truck.

Wow, there are so many inaccurate statements in this, that it's hard to cover all of them.

First off, not all HST transmissions are designed the same, and not all tractors are designed the same. My LS manual very specifically says to run the engine at 1500rpm+ when putting the engine under load...if it needed to be at PTO speed, or max speed to keep the transmission cool enough, or prevent other wear, they would say so.

Running a hydraulic pump at max RPM doesn't make it easier for the pump to do its job, it simply makes the pump put out more volume. Up to a certain point, the added volume causes higher pressures, but that's usually a fairly low RPM....after that, it's just bypassed. Higher RPMs cause more wear to some parts (bearings, etc), and higher pressure causes more wear to other parts (seals, valves, etc), so the pump won't last longer run at max RPM.

Running at maximum RPM will cause a higher rate of wear on things like the bearings, pistons, rings, valves, etc, etc, etc. Usually just a slight decrease in RPM will cause a significant increase in longevity. People that suggest always running at WOT because "they're designed for it" simply don't know how engines work...

I rarely run at WOT, but I do when the situation calls for it. I know it can run at WOT for a long time, but making it do so for no reason is silly.