Question about hydraulics performance on different excavators.

[Hersheyfarm]

I have a kx040 I bought new last year. It’s just a hair too small. Looking at upgrading it to maybe a u48-5, or a Takeuchi tb250.

all 3 have the same hp, 39-40. Kx040, the u48, and the Takeuchi.

now my kx040 has 24.5 gpm single pump
The u48 has 32gpm single pump
The Takeuchi tb250 has 40gpm through 4 pumps, or 3 pumps and a forth for the 24 gpm auxiliary. So actually 3 pumps pumping the 40gpm.

the Takeuchi has better break out.

how does the number of pumps effect hydro capabilities with the same hp?
Doesn’t it still take the same hp to hydro flow, so wouldn’t the Takeuchi suffer from lack of power over the other machines trying to flow 40gpm?

one of my dislike with my kx040 is not being able to travel and use boom. Hydro flow gets cut in half. I blame the 24 gpm. Why wouldn’t they use the biggest pump that 40hp would pump?

 

[4570Man]

24 gpm at 3000 psi is already above the 40 hp available. The Tackuchi would have to choose between pumps or drop the pressure to half of the relief setting to get 40gpm. Personally I don’t see the u48 as a worthy upgrade and I would go for a KX-057. BTW were you the one that did the SVL75 hvac air filter upgrade?

 

[Vigo327]

how does the number of pumps effect hydro capabilities with the same hp?

They may not all be the same type of pumps. Some might be hydrostatic, some might be fixed displacement etc. As mentioned about the 40gpm at full pressure not even being possible with 24hp, one of things you might do with multiple pumps is use larger ones for circuits that require more flow and less pressure and smaller pumps for circuits that less flow but higher pressure. The larger one couldn't be pushed against a 3000psi 'head' without stalling the engine, but the smaller one can. Just examples.

Doesn’t it still take the same hp to hydro flow, so wouldn’t the Takeuchi suffer from lack of power over the other machines trying to flow 40gpm?

As mentioned you aren't really using 40 gpm anyway unless you're like rolling downhill with no resistance while using the hydraulics for some reason and running the engine at redline.

In reality the forces at the bucket are generated as much by geometry as they are by flow and pressure. GPM just gets you speed, and on a mini-x it's as much intended towards the speed of hydraulically driven motorized attachments as it is for the actual excavator itself. Pressure pushing on area is what gives you force out of the cylinder, and a larger bore cylinder will give more force at the same pressure. Then you hook the cylinder to an articulating linkage with a large 'motion ratio' ie the cylinder moves by twice as much as the bucket does, and you increase that force again. You could build a machine that pushes as hard at 500psi as another machine at 5000psim, but it's easier and cheaper to do what we actually do, which is increase pressure to DECREASE the required size of all the components.

But basically if some excavator has a bunch more GPM than another one in the same weight class, they're mostly just trying to appeal to people who are going to hang some hydraulically powered attachment off it, and only SOME of the total GPM of the machine will be available for that.

 

[dirttoys]

Depends on what pump runs what, I believe different pumps run different circuits. Usually you want to be able to move the bucket and arm without competing. Being able to walk and chew gum is rare in a mini, I have a 235 little brother to the 250, you can't really use the boom and travel, I believe the 250 is the same design.

Best,

ed

 

[Hersheyfarm]

One correction, the u48-5 is a 3 pump system. 31gpm across 2 pumps with auxiliary on 3rd?
Not sure of pressure kubota doesn’t seem to publish it.

 

[Hersheyfarm]

Depends on what pump runs what, I believe different pumps run different circuits. Usually you want to be able to move the bucket and arm without competing. Being able to walk and chew gum is rare in a mini, I have a 235 little brother to the 250, you can't really use the boom and travel, I believe the 250 is the same design.

Best,

ed

Is yours a cab machine? How you like it? Any issues? The cab of the Takeuchi is a little less refined than kubotas I’ve noticed.

 

[dirttoys]

Is yours a cab machine? How you like it? Any issues? The cab of the Takeuchi is a little less refined than kubotas I’ve noticed.

2014 yes it is cabbed heat/ac.

The few others I have ran were open station, so I don't have an educated opinion on a comparison.

It has been a good machine for me.

I have replace a couple of damaged hoses, and put shoes on it. I bought it with 1250 hours on it, it is just crossing 2000 now.

AC could be colder, there are plenty of times I wished I could reach a little further, or lift just a hair more.

That said, in the size range I would buy it again.

Let me know if there is anything more specific.

Best,

ed

 

[LD1]

The number of pumps will have little effect on how the machine performs. More important is how the pumps are setup and configured.

GPM = speed. NOT power.

You are looking at upgrading from a 4-ton class machine (relatively uncommon as most MFG's jump from 3.5t to 5t machines). The two you are looking at are both 5t class machines. The differences is small. But you do say that yours is "slightly" too small.

So I would question just what about your machine makes you think its too small. Is it reach, power, weight to lift something specific? Cause just digging trenches or footings there is gonna be little noticable difference in a 4t vs a 5t machine.

The single biggest difference I see is that you currently have a conventional mini and are looking at a pair of zero tail swing mini,s. And the zero tail swing machines sit overtop of tracks that are about a foot wider and a foot longer than a comparable sized conventional machine.

Also worth consideration is what you are trailering it with. The 5t class machines are at the limit of a 14k trailer. Whereas your KX040 has alot of wiggle room and can even be towed on a 12k trailer. IF that is a concern for you or not

 

[Fixastuff]

Get them each to drop a machine off for you to demo on your farm. That's the really the only way to know how what your buying will perform. I've found machines in the same weight class a zero tail won't perform a well as one with counterswing when it comes to lifting or feeling stable without the blade down.

 

[4570Man]

The number of pumps will have little effect on how the machine performs. More important is how the pumps are setup and configured.

GPM = speed. NOT power.

You are looking at upgrading from a 4-ton class machine (relatively uncommon as most MFG's jump from 3.5t to 5t machines). The two you are looking at are both 5t class machines. The differences is small. But you do say that yours is "slightly" too small.

So I would question just what about your machine makes you think its too small. Is it reach, power, weight to lift something specific? Cause just digging trenches or footings there is gonna be little noticable difference in a 4t vs a 5t machine.

The single biggest difference I see is that you currently have a conventional mini and are looking at a pair of zero tail swing mini,s. And the zero tail swing machines sit overtop of tracks that are about a foot wider and a foot longer than a comparable sized conventional machine.

Also worth consideration is what you are trailering it with. The 5t class machines are at the limit of a 14k trailer. Whereas your KX040 has alot of wiggle room and can even be towed on a 12k trailer. IF that is a concern for you or not

I agree that the hydraulic specs is barking up the wrong tree. If you want a bigger excavator buy one that’s bigger. I also agree that a u48 isn’t really a worthy upgrade. I’d be looking at a Kx057 or for little bigger than that a Deere 60. Also a KX40 really isn’t a 4 ton machine. It’s a few hundred pounds short of the 5 ton mark. I also agree with trailering the 6 ton machine. That problem along with about a 10k price increase is why I don’t have one. You’re probably going to be disappointed looking for a mini x that can track and use the boom at the same time. But I’d go demo the Takeuchi and see if it’s better. I’ve never ran a Takeuchi mini x but the Takeuchi skid steer line hasn’t left me impressed. It wasn’t bad but I didn’t leave impressed either.