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.
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.
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.
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.
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!
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.
It has both high and low using two sets of outlets and a case drain. It uses a solenoid to control which outlets, high or low, get pressure.
Put the mower on the machine, connect to the standard auxiliaries, put your earmuffs on, pin the throttle and go work. Everything will be happier this way . . .
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.
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.
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.
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.
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.
That can't quite be right, according to Willie's specs posted there would be 36,800 hp. Is there a formula for that?
I simply pulled the numbers from the Case spec sheet
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!
I cranked the relief valve down to increase it to 3,000 psi. It has made a HUGE difference. The mower was virtually unusable at 2300 psi. It would stall on everything it hit. That was a few years and a couple hundred hours of mower operation ago. I've not seen any ill side affects "so far." YMMV. If I could just get it spinning quicker, I'd have a great setup for what I use it for.
I've pretty much resigned to the fact that I am going to have to pin it and go or find a higher flowing XT series.
If you have enough flow higher pressure will give you more more torque/ power than increasing the flow. If you only had 2000 PSI you could have 50 GPM but your motor would just stall. 25 GPM at 3000 PSI would be much more effective. Flow x pressure is deceiving. Kind of like the ridiculous air compressor ratings. A 6.5 HP motor will not run on 120 volts.
Formula is: GPM x PSI / 1714 = HHP 1845c: 16 x 2300 /1714 = 21.47 hp
This is only true if you have the wrong size motor on the brush cutter for the skid steers flow AND psi. It's much like gearing. You can always trade flow & psi for any speed or torque you want. You do that by changing the size of the motor. Same thing applies to snowblower. Has to match the machine. Problam is the 1845c doesn't have great flow or psi. So you will never get an attachment that needs a lot of Hyd hp to work well. It will always be a compromise. This is very true. But it you understand electricity, it's exactly the same.
The 1845C was designed way before the attachment craze hit. Flow and PSI were not a big concern, as evident by the 56 hp. The XT series was designed as an attachment carrier offering an optional 5K psi high flow system on the 90-95XT.
Nailed it!
If you need a certain flow or pressure, increasing the other to compensate isn't a work around.