The neighbor has a Case 1845c with factory high flow auxiliary kit that puts out 30gpm. The factory auxiliarys run at 16 gpm. My CID Extreme brush cutter is designed for 20 gpm. My question is, if I adapt the hoses/couplers on my cutter to fit the high flow, and keep the throttle at under 1600 rpm which should be close to 20 gpm, am I going to run into any other problems. I am able to run my current Case 1840 (15 gpm) with the brush cutter at half throttle and it doesn't run out of power, so I don't see a power shortage being the issue by running the 1845 at half throttle. My issue with my 1840 is that it takes forever to get the mower wound up if I stall it (I'm clearing an old over grown pasture with it). If I run it wide open, I get my blades going faster, but it sure does drink the fuel and I feel like it would be unnecessary if I just had a higher output pump. I'm not looking at getting a different machine, different cutter, different hobby, etc. What I'm really curious on is if anyone else does (or even can) run low flow attachments on high flow ouputs. Thanks for everyone's help in advance.
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Running a low flow brush cutter on a high flow machine
- Thread starter Skidud
- Start date
bad Tom
Well-Known Member
The only way to know how much flow you have is connect to a flow meter and check it at different engine speeds. The brush cutter I have is for 15 to 25 GPM. The hydraulic motor is only 20 GPM max. I am running more gallons a minute more than it can handle and I had to replace the control valve on the mower because it was dumping oil all the time and took out one of the valves.
When my employer purchased a small brush cutter, they emphasized the importance of not overrunning what the attachment's hydraulic motor can handle. I feel comfortable in setting the RPMs on the skid steer so that the flow matches the attachment based off the cc/rev output of the hydraulic pump. My concern is more on not finding any information anywhere of others doing what I am contemplating. I feel like this is surely being done, but I can't find any discussion about it, good or bad. I don't know what issues I would have if I run the proper flow, but other's experiences would hopefully shed light on it. Does the high flow pump need to be run at X rpms for some reason?? Will the skid steer catastrophicly fail if run at 1600 rpm instead of 2200??? Issues like that.
bad Tom
Well-Known Member
I don't think you could do any damage to the loader running it at that rpm. I don't run my loaders wide open now.
Welder Dave
Senior Member
Could you put a priority flow divider in the line to limit flow to 20 GPM at full throttle? Skid steers are designed to be run full throttle. It's easier on the hydrostat components. The other thing to be even more concerned with is the pressure rating of the motor. Most high flow machines run higher hyd. pressure at the remotes than the standard 2500 PSI. I think some are 3500 PSI. You don't want to blow up the motor if it's not designed for higher pressure.
willie59
Administrator
Someone correct me if I'm wrong, but don't high flow option machines have a feature that allows you to select to engage high flow? After all, if all a high flow machine could produce is high flow then you'd have fun operating the itty bitty cylinders on a grapple, would give new meaning to WHAM!
Welder Dave
Senior Member
I don't know if an 1845C high flow also has standard flow aux. hyd's.? A lot of high flow also have a case drain line.
Welder Dave
Senior Member
What is the high flow pressure and what is the hyd. motor design pressure? I don't think you'd be happy running only half throttle.
I am not sure on the high flow pressure. I believe I read 3000 psi. The cutter has a crossover return bypass built into the hoses set at 3000 psi. I'd have to test the high flow to be sure, but if it were any higher than, I'd not consider it. I don't want it trying to bypass the whole time.
Apparently running low flow attachments on high flow circuits is not a common practice, or at least not common enough to get any positive or negative feedback from it. I appreciate everyone's input. If I do decide to give it a whirl, I'll follow up and let everyone know how it goes. At this point, I'm probably not going to push the issue. I"ll just run my standard auxiliaries and take my time.
willie59
Administrator
Generally speaking, pressure between high flow and low (standard) flow is the same, they're both capable of putting out X amount of pressure depending on how the system is designed. The difference between the two is flow of oil, gpm/lpm of oil output from the pumps, high flow puts out more volume of oil than standard flow to run larger motors and such that standard flow doesn't have enough output to operate. Sorta like attempting to air up a truck tire with a bicycle pump. The bicycle pump can produce the pressure, but lack out flow output...you gonna be there a while.
Welder Dave
Senior Member
I thought most high flow attachments need increased flow as well as pressure to get higher hyd. HP. More flow doesn't give any more power, only speed. Higher pressure gives more torque.
phil314
Senior Member
Flow x PSI = Hyd HP.
Most skid steers the low and high flow will run the same pressure.
The speed and torque of the brush cutter depends on the size of it's motor and the Hyd HP provide.
Not directly on the flow and PSI.
That's why it's important to match the motor size to the skid steer.
For the OP, you should be able to just directly connect the brush cutter to the low flow connectors and run as much throttle as you want.
Most skid steers the low and high flow will run the same pressure.
The speed and torque of the brush cutter depends on the size of it's motor and the Hyd HP provide.
Not directly on the flow and PSI.
That's why it's important to match the motor size to the skid steer.
For the OP, you should be able to just directly connect the brush cutter to the low flow connectors and run as much throttle as you want.
willie59
Administrator
The specifications on a Case 1845C has the main hydraulic relief valve set at 2300 psi. Standard aux specs are 16 gpm @2300 psi, the main relief setting. The high flow option will deliver 30 gpm @, you guessed it, 2300 psi, the main relief setting. The most pressure your going to get out of the aux, low or high flow, is what the main relief will allow, and on that machine, 2300 psi max.
Acoals
Senior Member
That can't quite be right, according to Willie's specs posted there would be 36,800 hp. Is there a formula for that?
willie59
Administrator
I simply pulled the numbers from the Case spec sheet
Acoals
Senior Member
Those numbers look right, it's the Flow X PSI = Aux Hp formula that can't be right. 16gpm@2600psi is a lot more plausible that 36,800hp . . .
Exactly right!