My NX6010

[MinnesotaEric]

Nice job on the video Eric.

I've noticed in a couple of Kappers videos and this last video that you made the NX6010s engine seems to bog easily. I wonder what is up with that?

What is going on is that I'm auguring into a pile of dirt, and while still moving forward, hitting relief pressure on the loader and rather than backing off all the way, I'm working the forward and rearward pedals until the loader finds whatever it can lift while moving. While doing this the engine bogs and so I've got to back off just enough to allow the engine to spin back up, and then back into it!

However, if I'm trying to pick up a log that is too heavy but not moving forward or backward, so long as the engine is throttled up, the engine will not bog down. Instead it'll just go to relief.

The same thing happens with skid loaders too since they (or the ones I've seen) use open center pumps which can overwhelm the engine if they are loaded both by the HST and the hydraulic pump.

 

[94BULLITT]

What is going on is that I'm auguring into a pile of dirt, and while still moving forward, hitting relief pressure on the loader and rather than backing off all the way, I'm working the forward and rearward pedals until the loader finds whatever it can lift while moving. While doing this the engine bogs and so I've got to back off just enough to allow the engine to spin back up, and then back into it!

However, if I'm trying to pick up a log that is too heavy but not moving forward or backward, so long as the engine is throttled up, the engine will not bog down. Instead it'll just go to relief.

The same thing happens with skid loaders too since they (or the ones I've seen) use open center pumps which can overwhelm the engine if they are loaded both by the HST and the hydraulic pump.

It takes 14.9HP to operate your loader at max pressure and GPM, you are left with 45hp to "move" the tractor. 45hp should be more than enough hp to propel a tractor that is under 7,000lbs especially without a ballast on the 3PH because it will spin easier without a ballast.

 

[94BULLITT]

What is going on is that I'm auguring into a pile of dirt, and while still moving forward, hitting relief pressure on the loader and rather than backing off all the way, I'm working the forward and rearward pedals until the loader finds whatever it can lift while moving. While doing this the engine bogs and so I've got to back off just enough to allow the engine to spin back up, and then back into it!

However, if I'm trying to pick up a log that is too heavy but not moving forward or backward, so long as the engine is throttled up, the engine will not bog down. Instead it'll just go to relief.

The same thing happens with skid loaders too since they (or the ones I've seen) use open center pumps which can overwhelm the engine if they are loaded both by the HST and the hydraulic pump.

It takes 14.9HP to operate your loader at max pressure and GPM, you are left with 45hp to "move" the tractor. 45hp should be more than enough hp to propel a tractor that is under 7,000lbs especially without a ballast on the 3PH because it will spin easier without a ballast.

 

[ksbrdmkr]

tractor is not 7000 lbs when the loader is at the max lifting force/relief valve and in 4 wheel drive.

 

[MinnesotaEric]

tractor is not 7000 lbs when the loader is at the max lifting force/relief valve and in 4 wheel drive.

And the additional 1250 pounds of Rim Guard in all four tires as well as the 150 pounds go CAT 2 Quick Hitch.

Figure the loader is 1100ish pounds (wild guess since I've never seen a weight spec on the KL6010 loader), the bucket its at least 300 pounds, the tractor 4600ish pounds, 1250 pounds of ballast, 150 pounds for the quick hitch, and we're at 7100 pounds. Now figure the loader is attempting to pick up 3000 pounds because we're both driving in and lifting at the same time (official loader rating is 2700 pounds).

That said, 94BULLITT, where did the 14.9hp spec come from? If true, I should have maximum lift at idle, but I don't. I do not doubt your sincerity, but that number cannot be right. If my tractor only needs 14.9 horsepower to generate maximum pressure and maximum flow in an open center system under maximum load is really true, then 25hp subcompact tractors should have monster lift specs, and I and everybody else have been taken. Consider that if 14.9 hp is true, then Island's outrageous argument is right: his little tractor can do everything the bigger NX series can do and do it just as fast as the larger, faster NX series and we're all fools for buying bigger tractors!

 

[IslandTractor]

I would imagine the 15 hp figure is about right. My DK40 has exactly the same lift capacity as the NX6010. 2760lbs. There is a big difference at the PTO end but not much if anything with the loader.

 

[MinnesotaEric]

Sigh. Okay the only thing the engine is spinning is a hydraulic pump. The pump is positive displacement, meaning that what goes in must come out or it explodes or stalls.

Ask yourself, if the engine is running faster or slower, if there a difference in flow?

Answer: yes, there is a difference in flow.

Ask yourself, is the pump able to go to relief pressure at idle?

Answer: yes. It is possible to nab something with the loader at idle and go to relief.

Ask yourself, why then is more lifting power available at high engine speed?

Answer: the volume of flow. The speed of flow allows more work to be done even as the relief is varying its opening and blowing off excess pressure. This is because pressure on fluid is the same everywhere when the fluid isn't moving but this isn't true when the fluid is moving. At low volume, a given ram will not move under a given load because the relief opens before enough volume of fluid can develop to overcome the load. At higher volume, enough fluid is moving to fill the ram to keep it moving even as excessive pressure is flowing past the relief valve. Thus more work is work is done with higher volume and higher engine power allows the work to be done faster on a given ram size than a lower engine speed or lower engine power. For this reason the 45-60hp NX series have the same spec loader lift spec ratings.

I tried to find an animation to show how this works as it isn't super intuitive. What I found is a closed center system animation. Fine, just presume, a valve that flows pump output back to tank when not working the valve rather than through the relief. what I liked about this animation is that it attempts to show pressure under different loads while the ram is moving and the speed at which work can be done. The animation doesn't get into fluid dynamics and Bernoulli's Equation, which is what I really wanted to try and show.

The basic take-away is that higher flowing fluid has lower pressure than slower moving pressure and so more work can be done before going to relief.

 

[MinnesotaEric]

Here is an explanation of Bernoulli's Equation.

 

[IslandTractor]

Fine. I think Bernoulli is a great guy and I like drinking Heinekens with him when I visit Amsterdam but perhaps Blaise Pascal is more relevant here. For a given pressure created by the hydraulic pump and limited by the pressure relief valve, the output power acting on an identical cylinder would be the same. I don't see where having more power creating that same pressure makes much difference if any in this closed system. I believe the pumps on the two tractors are pretty similar in capacity (NX about 6-7% greater gallons/min than DK: 17.9 vs 16.8gpm). But the key point is that the pressure relief valve means that the extra power available on the NX cannot add significantly to loader function either in lift capacity or cycle speed under load. Without load both loaders (KL401 and KL6010) are rated at PTO RPM to raise the bucket in exactly the same time of 4.5 seconds. There might be a second or less advantage in raising a near capacity load to travel height. Big deal. They still raise exactly the same max load which is obvious given they have the same loader geometry, and cylinder size.

From a purely practical point of view, it's not like the DK40 requires ten minutes to lift a large stump or rock or chunk of concrete. I don't lift those things to full height but when I lift them running at 1800=2000rpm they come off the ground pretty much the same speed as when I am lifting an empty grapple at idle. Works for me. Certainly it doesn't take more than a few seconds more to reach carrying/transport height. What's the reason I would need more power to run my loader???

As noted earlier, if you are running something power hungry on the PTO then the extra horses mean something as they would towing a heavy trailer or big plow but as far as the loader is concerned a 40hp Kioti ends in a dead heat with a 60hp Kioti.

By the way, you were wondering what your loader weighs. Given that the KL401 weighs 1284lbs, I cannot imagine the KL6010 weighs much more.

 

[94BULLITT]

That said, 94BULLITT, where did the 14.9hp spec come from? If true, I should have maximum lift at idle, but I don't. I do not doubt your sincerity, but that number cannot be right. If my tractor only needs 14.9 horsepower to generate maximum pressure and maximum flow in an open center system under maximum load is really true, then 25hp subcompact tractors should have monster lift specs, and I and everybody else have been taken. Consider that if 14.9 hp is true, then Island's outrageous argument is right: his little tractor can do everything the bigger NX series can do and do it just as fast as the larger, faster NX series and we're all fools for buying bigger tractors!

I looked up the specs for your loader, the GPM (10GPM) and pressure (2556psi). http://www.kioti.com/products/attachments/front-end-loaders/kl6010/

Here is the formula. 10x2556=25,560/1714=14.91HP I have very close to max lift at idle with the L4240. I don't have a way to compare and see how much it will lift at idle and full throttle but it not much of a difference. Horsepower has nothing to do with lift specs on a tractor. The size of the cylinders on the loader and the relief valve setting on a loader are what it important. I could take CS2410 and put larger cylinders on the loader to make it lift more. The loader cylce times would be slower though. As far as the debate on HP, if Island tractor is pulling a box blade with his DK40 and it fills up and the tractor looses traction what good would more power be? Where you will really notice more power is driving the tractor down the road. The tractor with more power will pull the hills better. More power will allow you to run larger PTO driven implements.

Here is a video where I noticed bogging, even at 1:20 backing up.

Sigh. Okay the only thing the engine is spinning is a hydraulic pump. The pump is positive displacement, meaning that what goes in must come out or it explodes or stalls.

Ask yourself, if the engine is running faster or slower, if there a difference in flow?

Answer: yes, there is a difference in flow.

Ask yourself, is the pump able to go to relief pressure at idle?

Answer: yes. It is possible to nab something with the loader at idle and go to relief.

Ask yourself, why then is more lifting power available at high engine speed?

Answer: the volume of flow. The speed of flow allows more work to be done even as the relief is varying its opening and blowing off excess pressure. This is because pressure on fluid is the same everywhere when the fluid isn't moving but this isn't true when the fluid is moving. At low volume, a given ram will not move under a given load because the relief opens before enough volume of fluid can develop to overcome the load. At higher volume, enough fluid is moving to fill the ram to keep it moving even as excessive pressure is flowing past the relief valve. Thus more work is work is done with higher volume and higher engine power allows the work to be done faster on a given ram size than a lower engine speed or lower engine power. For this reason the 45-60hp NX series have the same spec loader lift spec ratings.

I tried to find an animation to show how this works as it isn't super intuitive. What I found is a closed center system animation. Fine, just presume, a valve that flows pump output back to tank when not working the valve rather than through the relief. what I liked about this animation is that it attempts to show pressure under different loads while the ram is moving and the speed at which work can be done. The animation doesn't get into fluid dynamics and Bernoulli's Equation, which is what I really wanted to try and show.

The basic take-away is that higher flowing fluid has lower pressure than slower moving pressure and so more work can be done before going to relief.

I agree

 

[MinnesotaEric]

I looked up the specs for your loader, the GPM (10GPM) and pressure (2556psi). http://www.kioti.com/products/attachments/front-end-loaders/kl6010/

Here is the formula. 10x2556=25,560/1714=14.91HP I have very close to max lift at idle with the L4240. I don't have a way to compare and see how much it will lift at idle and full throttle but it not much of a difference. Horsepower has nothing to do with lift specs on a tractor. The size of the cylinders on the loader and the relief valve setting on a loader are what it important. I could take CS2410 and put larger cylinders on the loader to make it lift more. The loader cylce times would be slower though. As far as the debate on HP, if Island tractor is pulling a box blade with his DK40 and it fills up and the tractor looses traction what good would more power be? Where you will really notice more power is driving the tractor down the road. The tractor with more power will pull the hills better. More power will allow you to run larger PTO driven implements.

Here is a video where I noticed bogging, even at 1:20 backing up.

I agree

Okay, I'm tracking with you.

I found a simplified cheat-sheet for everybody reading along.

http://web.applied.com/assets/attachments/779D4407-D2AE-6FAA-7DA1CEDE2268977B.pdf

Our formula is hp = gpm x pressure / 1714

I puzzled out part of this in paging through my service manual at some point for somebody and have the benefit of leaving myself some notes on the calculated flows as rated by volume per engine revolution.

The NX series opens its relief at 3271 psi and then settles down to 2560 api according to page 11-3 in the NX service manual. The HST models flow more fluid than the gear versions. Hydraulic flow is slightly less than the spec you used at 9.615 gpm. Total flow with both sides of the pump for hydraulics, power steering, and the HST transmission is 17.857 gpm. Neither of those specs are published that accurately, but I did the math on another day and figured out the gpm flow rates.

We take these revised numbers with slightly less gpm, but higher peak pressure at we arrive at 18.34 hp for the hydraulics and a total for the pump at 34.07 hp. The engine pumps out just shy of 60hp and around I think I recall something like 140-50 ft. pounds of torque. In context, the engine should never bog, but due to restrictions, bends, the water pump, alternator, charge pump, internal frictions, and losses in the fluid to heat, we arrive at an engine that bogs down when auguring into something and due to momentum, overwhelming its own specs. Doubtlessly a larger engine with more tore to its hp rating would do better, but I've been pleased with my NX's performance.

Anyway, thanks. I learned through this.

 

[countrybumpkin]

While we are on the hydraulic topic, has anyone with a NX checked the hydraulic oil temp after running a rotary cutter for a couple of hours ? Ive been meaning to check the filter temp and the rear remote block temp with a temp gun but keep forgetting to put it in the tractor with me.

 

[ksbrdmkr]

My thought is the engine can pop the relief valve at idle or full throttle, but the system pressure will be higher with the full throttle because the relief valve has a huge amount more of fluid to bypass.

 

[IslandTractor]

My thought is the engine can pop the relief valve at idle or full throttle, but the system pressure will be higher with the full throttle because the relief valve has a huge amount more of fluid to bypass.

If so, then why does the 40hp tractor raise its FEL exactly as fast as the 60hp tractor using essentially the same loader? And why do the have identical lift capacities?

 

[MinnesotaEric]

While we are on the hydraulic topic, has anyone with a NX checked the hydraulic oil temp after running a rotary cutter for a couple of hours ? Ive been meaning to check the filter temp and the rear remote block temp with a temp gun but keep forgetting to put it in the tractor with me.

I have not, but I have thought about getting my oil tested after my midpoint PTO sprung a leak and I swapped out my tranny hydro oil with 50 hours on it and it was darker color than I expected it to be. Through TBN's private messaging I consulted with MHarryE, writing,

...do you know of a good oil sample shop in Nevis, Park Rapid, Walker area?

I've noticed that my hydro/HST oil smelled a little burnt after 50 hours and I've got two restrictions in my main power beyond line, the first through a D3 sub plate (running my third loader function), and the second through a 3rd set of rear remotes (the factory only officially blesses two sets, and using a cheap pyrometer, the entire stack is only adding about 10 degrees). The open center pump flows less than what a D3 sub plate can take (9.615 gpm at 2600 rpm). Anyway, a little burnt smell may be completely acceptable or normal, but I'd like peace of mind.

MHarryE responded explaining that he had just found out who does sample testing and found our local Zeigler shop is about the only oil lab in northern MN. I plan on picking up oil sample jars the next time I visit a Zeigler dealer.

What I can also tell you, and this is buried way, way back in this thread is that after running my rotary cutter for a couple of hours, I hit my rear remote stack with a pyrometer. Recalling that for reasons nobody has yet discovered, Kioti only offered two sets of valves in the rear, and I had my dealer install three sets of valves (one number one kit, and two number two kits, as I recall), three valves increased the hydro oil temp by ten degrees measured externally. The top the stack, as I recall, was 110 degrees and the bottom of the stack was 120 degrees. Granted the fluid is warmer inside the housing, but I didn't think that temperature was anywhere near cause for concern when I consulted temperature charts. Also, given that I'm in Minnesota and that cold hydro oil can be a death blow to pumps, added a few degrees into the oil through the third function restriction and the stack of three rear remote valves I considered a positive, so long as the heat doesn't get out of hand during longer hours of operation during the summer.

My plan is to sample the hydro fluid at 250 oils, send it in for testing, and if MHarryE is so willing, consult with him about the results of the sample test. I'll post my findings n this thread. My tractor currently has about 190 hours on it, and since I'm selling a city house, I don't expect to hit 250 hours until next year sometime.

 

[countrybumpkin]

Ok I would be curios to see what the analysis comes up with. 110 degree after a couple hrs seems to be a bit low to me mine sure seems to be hotter than that for sure. I'll defiantly have to check the temp of mine at least with a temp gun if nothing else.

 

[94BULLITT]

Okay, I'm tracking with you.

I found a simplified cheat-sheet for everybody reading along.

http://web.applied.com/assets/attachments/779D4407-D2AE-6FAA-7DA1CEDE2268977B.pdf

Our formula is hp = gpm x pressure / 1714

I puzzled out part of this in paging through my service manual at some point for somebody and have the benefit of leaving myself some notes on the calculated flows as rated by volume per engine revolution.

The NX series opens its relief at 3271 psi and then settles down to 2560 api according to page 11-3 in the NX service manual. The HST models flow more fluid than the gear versions. Hydraulic flow is slightly less than the spec you used at 9.615 gpm. Total flow with both sides of the pump for hydraulics, power steering, and the HST transmission is 17.857 gpm. Neither of those specs are published that accurately, but I did the math on another day and figured out the gpm flow rates.

We take these revised numbers with slightly less gpm, but higher peak pressure at we arrive at 18.34 hp for the hydraulics and a total for the pump at 34.07 hp. The engine pumps out just shy of 60hp and around I think I recall something like 140-50 ft. pounds of torque. In context, the engine should never bog, but due to restrictions, bends, the water pump, alternator, charge pump, internal frictions, and losses in the fluid to heat, we arrive at an engine that bogs down when auguring into something and due to momentum, overwhelming its own specs. Doubtlessly a larger engine with more tore to its hp rating would do better, but I've been pleased with my NX's performance.

Anyway, thanks. I learned through this.

That PDF has some handy stuff. I'm gonna print it.

Okay, 34hp maxing everything out. You are never going to max everything out at the same time but there really is not another way to figure it. So you have a 60hp tractor then max out the hydraulics you are left with 26hp. Kubota gives numbers for gross and net HP. For the L6060 it is 62 gross HP and 60 net HP. If we take away 2hp to for a net(alternator and water pump) you still have 24hp to spare. Then what does a/c use on a tractor? I don't think it is very much. I'll be generous and say 5hp. Now you have 19hp to spare with the hydraulics all maxed. With the hydraulics all maxed shouldn't the engine stay revved up and the hydraulics all hit the relief?

If so, then why does the 40hp tractor raise its FEL exactly as fast as the 60hp tractor using essentially the same loader? And why do the have identical lift capacities?

It is not really related to power, it is related to RPM. At a higher RPM the pump is turning faster creating more GPM.

 

[MinnesotaEric]

With the hydraulics all maxed shouldn't the engine stay revved up and the hydraulics all hit the relief?

With the engine revved up, the loader maxed, the engine stays revving and the hydro goes to relief. The HST, pump can stall the engine when under a load and combos of the HST pump and load on the loader can and does stall the engine even with anti-stall switched on (a feature, I've never puzzled out what it tries to do).

 

[94BULLITT]

With the engine revved up, the loader maxed, the engine stays revving and the hydro goes to relief. The HST, pump can stall the engine when under a load and combos of the HST pump and load on the loader can and does stall the engine even with anti-stall switched on (a feature, I've never puzzled out what it tries to do).

The stall guard on Kubotas opens the swash plates to keep the engine from stalling. The tractor accelerates faster with it on, pulls hills better, and it kicks in under a heavy load like while grading or digging wit the loader, improving performance. I was going up a steep hill in High range and turned stall guard off and the tractor dropped 2MPH instantly.

 

[MinnesotaEric]

The stall guard on Kubotas opens the swash plates to keep the engine from stalling. The tractor accelerates faster with it on, pulls hills better, and it kicks in under a heavy load like while grading or digging wit the loader, improving performance. I was going up a steep hill in High range and turned stall guard off and the tractor dropped 2MPH instantly.

There is a difference with stall-guard on or off, but I never geeked out enough to find out how it works. Since this is an electrically controlled HST, without checking, I presumed that when the engine started to stall, the ECU backed off the user requested load from the forward and rearward signal sent to the HST computer even if the user continued to mash the go pedal all the way down, but I don't really know.

I suppose in the time I took to type this, I could look it up.

<Time goes by>

Nope. The service manual doesn't share how the no stall switch works. On page 12-91 of the service manual It says that with the no stall switched on is there to protect the engine during loader work in case of momentary engine overload. I'd need to study the wiring guides and even then, it likely is a software thing buried in either the ECU or the HST controller, and unlikely the safety controller (land of all safety switch interruptions), but who knows.