Dpm708
Member
Does anyone have a spec sheet or whatever relating to the Hyd pressure put out at any given RPM for the BX 25? And what would be relief spring pressure? Thanks.
PSI/RPM curve for BX 25
- Thread starter Dpm708
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Stonehaller
Platinum Member
I think the BX25 relief pressure is about 1800 psi. The pressure will not vary with RPM, at least not significantly. The relief valve is not perfectly linear and you will see a small increase in pressure from low to max RPM.
The flow rate, however, will be proportional to the RPM. Think of the flow rate as velocity, i.e. how fast your cylinders will move. Think of pressure as force how much you can lift with you FEL.
The flow rate, however, will be proportional to the RPM. Think of the flow rate as velocity, i.e. how fast your cylinders will move. Think of pressure as force how much you can lift with you FEL.
keyman1808
Platinum Member
I dont have the actual specs but I find that the FEL works good at about 1900 RPM on up. The BH likes 2800 RPM and higher but thats on my BX24.
radioman
Super Member
I'm gonna agree with that.
One thing you want to keep in mind- using too low of RPM with heavy work for slower precise handling, it can cause hydro captivations in the pump- (eek!) .
Yankee Clipper
Gold Member
DPM,
The BX25 hydraulic pump flow rate is 6.6 GPM at 1500 RPM - the first 2 gallons go to steering via the prioroity valve and you can not recover them as they go back to tank. That leaves you with 4.6 GPM to do whatever else on the tractor. Stonehaller is right that the flow is proportioinal to the engine RPM and you should throttle up if you want speed / increase in flow rate.
The relief pressure is 1778-1849 PSI - it is pilot operated so it will start to crack at about 90% of this pressure.
YC
The BX25 hydraulic pump flow rate is 6.6 GPM at 1500 RPM - the first 2 gallons go to steering via the prioroity valve and you can not recover them as they go back to tank. That leaves you with 4.6 GPM to do whatever else on the tractor. Stonehaller is right that the flow is proportioinal to the engine RPM and you should throttle up if you want speed / increase in flow rate.
The relief pressure is 1778-1849 PSI - it is pilot operated so it will start to crack at about 90% of this pressure.
YC
CHDinCT
Veteran Member
Can't tell you what the psi curve is with rpm, but I believe it is relatively flat as Stonehaller states. I have checked my PSI with a gauge and it read right under 1800 psi but I don't recall what rpm that was at, BUT,
I had previously owned a JDX485 that spec'd out at 1000 psi. I ran a test on it with a pressure gauge and got 950 psi at idle and 1050 at full rpm, a mere 100 psi difference.
I had previously owned a JDX485 that spec'd out at 1000 psi. I ran a test on it with a pressure gauge and got 950 psi at idle and 1050 at full rpm, a mere 100 psi difference.
Stonehaller
Platinum Member
My guess is at idle that all the pump flow is going to the power steering. At higher RPM there is enough pump volume for oil to be routed to the hydraulics.
Nightforce
Silver Member
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- Aug 6, 2014
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- Rehoboth, MA
- Tractor
- Kubota BX25D, John Deer D140, Craftsman GT6000
BX25D
As you can see by the information below, there is a significant difference in pump output pressure at an idle vs the working rpm range. Do the math and see how this difference equates to force and lifting ability.
Hydraulic Pump Pressure
1500rpm
3000rpm
As you can see by the information below, there is a significant difference in pump output pressure at an idle vs the working rpm range. Do the math and see how this difference equates to force and lifting ability.
Hydraulic Pump Pressure
1500rpm
3000rpm
