KX057, Combine Aux Flow?

[lumberjack]

My 057 has the dual aux option, ~10 and ~20gpm. My question is can those flows be combined for a theoretical ~30gpm?

I realize I could turn the pressure up on the second aux and approximate the same hp, but one stump grinder I'm looking at has a flow range of 25-40gpm which means I could use it on the ex and CTL. A simple y connector on the pressure line would handle combining the flow (one way).

In my testing dead heading the circuits, both add load to the engine individually and combined. I realize I'll likely need to add cooling capacity.

Why won't it work?

 

[CooterBrown]

I wondered that as well. If possible it would be nice. If you can find someone with a flow gauge then you could check it.

 

[lumberjack]

Yeah, I'm going to call around and see if I can find one locally to test the idea, I'd rather not buy one but I'm keen on figuring it out!

 

[lumberjack]

I have a call in to my salesman who should be calling Kubota to ask their opinion... hopefully I hear something tomorrow.

 

[CooterBrown]

I have a call in to my salesman who should be calling Kubota to ask their opinion... hopefully I hear something tomorrow.

Any word yet?

 

[lumberjack]

The salesman said, Kubota said the cooling system and pumps weren't designed for it and that it would result in a failure. The cooling system I understand and agree that it would require more cooling, but the pumps concern I can't fathom.

 

[John C.]

It's not the pumps that are the issue. It is that the engine can't produce and carry the extra horsepower necessary to run that flow and pressure. What you are talking about is putting a 4BTCummins engine in a W900 Kenworth and expect it to pull 80,000 pounds over the Rocky Mountains.

 

[lumberjack]

That is incorrect, I can dead head both circuits without causing the engine to pull down.


The aux pressures are 2500psi; 30gpm at 2500psi is 43.75hp, which is doable. However the machine won't supply max pressure at max gpm, if it did, the air conditioner would put the engine near stalling and any additional load would certainly stall the engine.

 

[mikebramel]

That is incorrect, I can dead head both circuits without causing the engine to pull down.


The aux pressures are 2500psi; 30gpm at 2500psi is 43.75hp, which is doable. However the machine won't supply max pressure at max gpm, if it did, the air conditioner would put the engine near stalling and any additional load would certainly stall the engine.

If you are dead heading them the pump is only providing more than enough to dump over the relief valve not fully stroked so as John said it is not enough

 

[lumberjack]

The KX057 has 49.5hp, which is enough to produce 2.5ksi @ 29.6gpm (9.8+19.8) at the pump (47.5hp w/ 90% efficiency). At higher elevations (derated HP) it would stall the engine.


Still, that's a moot point as the pressure could be reduced to say 2.25ksi which would take ~43hp @90% efficiency.

 

[mikebramel]

Neither the pump or engine are designed for 100% duty cycle. Maybe 60-70

 

[CooterBrown]

The KX057 has 49.5hp, which is enough to produce 2.5ksi @ 29.6gpm (9.8+19.8) at the pump (47.5hp w/ 90% efficiency). At higher elevations (derated HP) it would stall the engine.


Still, that's a moot point as the pressure could be reduced to say 2.25ksi which would take ~43hp @90% efficiency.

Your machines flow is rated at about 1000 psi not at max pressure. It only makes about 20 hyd hp so there is plenty of engine hp left.

 

[roadrunner81]

My experience with the 057 is that its a great machine, digs awesome, pretty smooth and comfortable. Its short comings so far have been with the larger of the auxiliary circuits in that the rest of the machine and auxiliary will slow substantially when used together. I'd say if you want a good digger its a great machine but if you plan to have a mower or the like hanging off it the majority of the time I'd look else ware.

 

[roadrunner81]

The Takeuchi TB260 has an auxiliary rated at 27gpm.

 

[CooterBrown]

My experience with the 057 is that its a great machine, digs awesome, pretty smooth and comfortable. Its short comings so far have been with the larger of the auxiliary circuits in that the rest of the machine and auxiliary will slow substantially when used together. I'd say if you want a good digger its a great machine but if you plan to have a mower or the like hanging off it the majority of the time I'd look else ware.

I have a KX161 and does great with my mulching head.

 

[CooterBrown]

The Takeuchi TB260 has an auxiliary rated at 27gpm.

I almost purchased this machine and may still do it. It is best in it's class with that flow.

 

[John C.]

Rule of thumb is one horsepower per gallon per minute at 1,000 PSI. So 30 gallons per minute at 2,500 PSI is 75 horsepower.

Good luck with mating that attachment to the machine.

 

[willie59]

I was thinking along the lines of roadrunner81, the max pump output of the KX057 is just shy of 30 gpm. If you run an attachment that works in the 20 to 40 gpm range your not leaving much to operate boom functions when attachment is operating or you'll see attachment slow down when operating boom functions.

 

[lumberjack]

1gpm at 1ksi is .58hp. To make that pressure with say a gear pump, you would want ~.66-.75hp turning the pump.

GPMxPSI/1714=HP

 

[CooterBrown]

Excavators require very little flow for movement when the mulcher is running because of the way that you mulch. Gravity is your friend. The Cat 308 puts out 33 gpm with 55 engine hp and is a stellar performer.