Bobcat K series s330 Hydro pressure

[YellowDogSVC]

I just had my machine pressure tested.. I wasn't happy. I thought I had a reduction in hydraulic power and I was right. I originally pressure tested at around 39 gpm and about 3450 psi +/- which is above specs.

Today, after getting a complete service, I could achieve 37 gpm at virtually no pressure but my max pressure was only hitting about 2500 psi at 32 gpm. That sucks.

I admit that I don't understand the hydro pump the way I should. So, for those of you who REALLY know how the K series gear pump on an s330 works, what do you think? Can I adjust anything myself?

[ksss]

I just had my machine pressure tested.. I wasn't happy. I thought I had a reduction in hydraulic power and I was right. I originally pressure tested at around 39 gpm and about 3450 psi +/- which is above specs.

Today, after getting a complete service, I could achieve 37 gpm at virtually no pressure but my max pressure was only hitting about 2500 psi at 32 gpm. That sucks.

I admit that I don't understand the hydro pump the way I should. So, for those of you who REALLY know how the K series gear pump on an s330 works, what do you think? Can I adjust anything myself?



I am no hydraulic expert, but it sounds like you may have a relief valve problem. If your only getting 2500 psi than you must be getting fluid by passing the valves. Are seeing a problem with the hyd. fluid getting hot as well?

[Nelson M Martin]

I admit that I don't understand the hydro pump the way I should. So, for those of you who REALLY know how the K series gear pump on an s330 works, what do you think? Can I adjust anything myself?

Presuming you don't have a pump problem then yes you can adjust that yourself

[bobcat_ron]

Should have stuck with the Cat, someone posted specs on Bobcat's pressures as the flow goes up, and the higher it went, the less pressure it made.

[ksss]

Should have stuck with the Cat, someone posted specs on Bobcat's pressures as the flow goes up, and the higher it went, the less pressure it made.


There is obviously something wrong if the machine is only making 2500 psi.


Cats biggest machines with high flow make about 4400 psi and only about 33 gpm. No matter the OEM the flow and pressure are inversely proportional.

[jefftb]

I am no hydraulic expert, but it sounds like you may have a relief valve problem. If your only getting 2500 psi than you must be getting fluid by passing the valves. Are seeing a problem with the hyd. fluid getting hot as well?

Sounds that way to me. Does the machine sound like its going pressure relief prematurely (stop right there fellas, yeah the question involves premature relief but not that kind :rolleyes:).

You probably know the difference, the machine is just not as capable as it was....

Ohhh crap, I cannot continue this. Too many dadgum' disclaimers on this conversation.

You know what I mean.

[YellowDogSVC]

Should have stuck with the Cat, someone posted specs on Bobcat's pressures as the flow goes up, and the higher it went, the less pressure it made.

I could get 3000 psi at 24 gpm on low flow which doesn't make sense. Maybe flow meter was off a bit but we are looking into it.

Cat's XPS took a big hit, too, on pressure if I recall but it was better than Bobcat. Something is up for sure but I'm not going to bash my Bobcat..yet. I gave CAT nearly 3 weeks in the shop to fix a small problem.

Sounds that way to me. Does the machine sound like its going pressure relief prematurely (stop right there fellas, yeah the question involves premature relief but not that kind :rolleyes:).

You probably know the difference, the machine is just not as capable as it was....


Seems less capable on high flow. Doesn't really get too hot. Even if the pressure was inversely proportionate, 32 gpm at 2500 psi can't be right. The specs we were testing it against were 36.7 and 3300 psi.

If your only getting 2500 psi than you must be getting fluid by passing the valves. Are seeing a problem with the hyd. fluid getting hot as well? Not really. That's what's strange. It all looks normal in the gauges and engine lugs the same but it just "feels" wrong when it's in high flow and under a load. The machine was a beast when I first got it. Takes longer to do the same things now. I really, really like it and I'm hoping to be able to adjust it back to at least specs if not a little more.

[jefftb]

Hmmm, I'd look into the pressure control/relief valve or the pump. Does not sound much like hoses or piping.

Beyond the engine there's not much left in the system to drive this, valving or pump.

[ksss]

I could get 3000 psi at 24 gpm on low flow which doesn't make sense. Maybe flow meter was off a bit but we are looking into it.

Cat's XPS took a big hit, too, on pressure if I recall but it was better than Bobcat. Something is up for sure but I'm not going to bash my Bobcat..yet. I gave CAT nearly 3 weeks in the shop to fix a small problem.



Seems less capable on high flow. Doesn't really get too hot. Even if the pressure was inversely proportionate, 32 gpm at 2500 psi can't be right. The specs we were testing it against were 36.7 and 3300 psi.

Not really. That's what's strange. It all looks normal in the gauges and engine lugs the same but it just "feels" wrong when it's in high flow and under a load. The machine was a beast when I first got it. Takes longer to do the same things now. I really, really like it and I'm hoping to be able to adjust it back to at least specs if not a little more.


I doubt its as simple as an out of adjustment issue with pump or valves. If you had great pressure before and now you don't, thats not an adjustment, thats a component failure. Are you still under warranty?

[YellowDogSVC]

I doubt its as simple as an out of adjustment issue with pump or valves. If you had great pressure before and now you don't, thats not an adjustment, thats a component failure. Are you still under warranty?

My 1 year warranty is up but there is a 2000 hr warranty on other parts. Not sure what's covered. Maybe the flow meter was off? I can feel the difference when I work on high flow (only). Everything else checks out normal and feels right.

[jefftb]

Scary, but cavitation in the pump could cause this. Look for microscopic bubbles in the hydraulic oil. It scores the pump discharge plate and causes inefficiency in the system.

[YellowDogSVC]

what could cause the cavitation? I just had all the filters changed including the case-drain and everything looked good. The sight bubble never shows any bubbles.

I'll know more next week when my service manager goes over the numbers we got today. Maybe this is normal on a flow test.. ? Not sure. I thought I had higher numbers when I got the machine. Seems to me, though, if Bobcat advertises 3300 psi and 36.7 gpm, I should be closer to that so something may be up.

[Digdeep]

I just had my machine pressure tested.. I wasn't happy. I thought I had a reduction in hydraulic power and I was right. I originally pressure tested at around 39 gpm and about 3450 psi +/- which is above specs.

Today, after getting a complete service, I could achieve 37 gpm at virtually no pressure but my max pressure was only hitting about 2500 psi at 32 gpm. That sucks.

I admit that I don't understand the hydro pump the way I should. So, for those of you who REALLY know how the K series gear pump on an s330 works, what do you think? Can I adjust anything myself?

The S330 uses a gear pump that only puts out a specific flow at a specific rpm. I have no idea how someone told you that you were getting 39gpm@3450psi. That is over 78 hydraulic hp before you even factor in the inefficiencies of the pump which is usually about 10% (especially for a gear pump vs a piston pump). The S330 only puts out 85 net engine hp and close to 232ft lbs of peak engine torque at a lower than max engine rpm. Remember that your pump can only put out 39gpm at max pump rpm and the peak engine torque is experience much lower. So it is very unlikely that your machine ever really saw those actual hydraulic numbers come in only 7hp less than your engine can even put out unless someone really tweaked that machine outside of OEM specs.

I've personally seen and held in my hot little hand a graph from a test that shows the T320 with a max actual hydraulic hp of 51hp (I wish I could have kept it) and it has a more engine hp than the S330. I think the machine was only putting out about 12gpm at 3300psi.

For what it's worth the CAT XPS off of the 297C only had a actual peak hydraulic hp of 55hp. Don't be fooled by the 33gpm@4060psi. It only has a puny 3.3L engine witha peak torque of 217ft lbs. And besides, even though their system uses a load sensing piston pump it also has a some sort of "pressure compensator switch" in the system that drops the system pressure to 3335psi as soon as you "crack a line" by moving the pilot joystick. Don't ask me why. The test I saw was quite thorough and pointed out the stark difference between published specs and "real world" specs where the machine's ability to really turn the pumps under load to produce these numbers came down to the engines limitation as the pressure increased.

[YellowDogSVC]

The S330 uses a gear pump that only puts out a specific flow at a specific rpm. I have no idea how someone told you that you were getting 39gpm@3450psi. That is over 78 hydraulic hp before you even factor in the inefficiencies of the pump which is usually about 10% (especially for a gear pump vs a piston pump). The S330 only puts out 85 net engine hp and close to 232ft lbs of peak engine torque at a lower than max engine rpm. Remember that your pump can only put out 39gpm at max pump rpm and the peak engine torque is experience much lower. So it is very unlikely that your machine ever really saw those actual hydraulic numbers come in only 7hp less than your engine can even put out unless someone really tweaked that machine outside of OEM specs.

I've personally seen and held in my hot little hand a graph from a test that shows the T320 with a max actual hydraulic hp of 51hp (I wish I could have kept it) and it has a more engine hp than the S330. I think the machine was only putting out about 12gpm at 3300psi.

For what it's worth the CAT XPS off of the 297C only had a actual peak hydraulic hp of 55hp. Don't be fooled by the 33gpm@4060psi. It only has a puny 3.3L engine witha peak torque of 217ft lbs. And besides, even though their system uses a load sensing piston pump it also has a some sort of "pressure compensator switch" in the system that drops the system pressure to 3335psi as soon as you "crack a line" by moving the pilot joystick. Don't ask me why. The test I saw was quite thorough and pointed out the stark difference between published specs and "real world" specs where the machine's ability to really turn the pumps under load to produce these numbers came down to the engines limitation as the pressure increased.

Very Interesting to say the least. I have been told that these machines can be tweaked but I also have been told that the T320 and S330 actually use a different gear pump so in theory, the s330 could never reach the specs of the T320. The motors are the same but the T320 gets a bit more power out of more fuel delivery. This came from Bobcat technical support.
A couple of years ago I had an s300 G series that put out 34 gpm on the tests and a couple of K series that put out close to spec.

The S330 uses a gear pump that only puts out a specific flow at a specific rpm. I have no idea how someone told you that you were getting 39gpm@3450psi. That is over 78 hydraulic hp before you even factor in the inefficiencies of the pump which is usually about 10% (especially for a gear pump vs a piston pump).

I don't think the 39gpm was at 3450psi in retrospec. But that's what I was told within a few psi. It could have been 39 gpm at 2000 psi for all I know.

Remember the ASV real world tests of Bobcat and CAT xps?


Anyway, I'm going to get educated on this..been putting it off! :dizzy:

[AWJ Services]

Here are some formulas and info to read on.


http://www.hydroleduc.com/site/medias/_pdf/_en_micro_p_t_formula.pdf

http://www.surpluscenter.com/Hydraulic.htm


http://www.hydraulicspneumatics.com/200/TechZone/HydraulicPumpsM/Article/True/6428/TechZone-HydraulicPumpsM


http://www.progressivehydraulics.com/calchp.htm

[AWJ Services]

Hyd hp = gpm x pressure/ 1714

39 gpm at 3450 psi would be 77 hp which means it would take a min of 90 hp to make that and that would leave no power for anything else.
That means sitting still with the loader arms stationary.

I would love to see someone actually install a flow and pressure meter on skid steers and then mulch and log the data during a day to actually see what the actual hyd hp is available to the head.

[ksss]

Hyd hp = gpm x pressure/ 1714

39 gpm at 3450 psi would be 77 hp which means it would take a min of 90 hp to make that and that would leave no power for anything else.
That means sitting still with the loader arms stationary.

I would love to see someone actually install a flow and pressure meter on skid steers and then mulch and log the data during a day to actually see what the actual hyd hp is available to the head.


There is no doubt that it varies. When I am in rough ground conditions the engine actually labors moving the machine around with the mulcher engaged.


The BIC high performance hydraulic system I think is a lot of the answer. Its a purpose built system for mulching and other high demand applications. They only do CNH stuff. When my current 465 is ready to be traded, the next one will have the BIC high flow.

http://burlingtoninstallation.com/

[ksss]

I have the relief valves in my machine that the BIC unit has. That alone has made a huge difference. I ran unit the until exploded in fire and only had to cool down to put the fire out.:dizzy:

I am razzing myself. The relief valves that they use do work very well. I have yet to have to stop and let the unit cool down. As well as increasing my pressures for more performance at the head.

[AWJ Services]

The more pressure you make the less flow you will need to make the same hyd hp however as the pressure rises I am sure the pump losses efficiency.

So at 5000 psi you will need 26 gpm of flow to = 77 hyd/hp

Excavators are a much better platform for mulching due to the simple fact that virtually all of the pump flow can be directed to the attachment while cutting.
A carrier platform like a skid has to move the machine to engage the material being mulched therefore needing more engine hp to accomplish the nsame task.

To effectivley get 77 hyd/hp in a skid steer application I would think you would need close to double that in engine hp.

[YellowDogSVC]

A carrier platform like a skid has to move the machine to engage the material being mulched therefore needing more engine hp to accomplish the nsame task.

To effectivley get 77 hyd/hp in a skid steer application I would think you would need close to double that in engine hp.

When I mulch, I am set at 50% or less of normal speed. There is only one way to do a good job and get power to the head with a skid. GO SLOW. I see too many guys ramming trees and they wonder why it takes them 20 minutes to mulch a single tree. Finesse is the answer to lack of hp but it is always nice to have your machine working at peak levels.

[Digdeep]

There is no doubt that it varies. When I am in rough ground conditions the engine actually labors moving the machine around with the mulcher engaged.


The BIC high performance hydraulic system I think is a lot of the answer. Its a purpose built system for mulching and other high demand applications. They only do CNH stuff. When my current 465 is ready to be traded, the next one will have the BIC high flow.

http://burlingtoninstallation.com/

The BIC is a good system, but the limitation is still the engine hp and primarily the engine torque to drive the pump as the pressure (resistance to the attachment motor) increases. Not saying that this is the case with the Case (no pun intended), but you could have the best hydraulic system in the industry and it would be worth poo if the engine couldn't handle the loads to allow the system to work to full effectiveness. CAT and ASV (PT100) use very close to the same system (load sensing piston pumps), but the ASV smokes all comers due to its ability to drive it's pumps better than the CAT or anyone else out there- ASV vs. CAT 4.4L vs. 3.3L, 306ft lbs vs. 217ft lbs, 92net hp vs. 90net hp. CAT=33gpm@4061psi vs ASV= 40gpm@3650psi.

[ksss]

The BIC is a good system, but the limitation is still the engine hp and primarily the engine torque to drive the pump as the pressure (resistance to the attachment motor) increases. Not saying that this is the case with the Case (no pun intended), but you could have the best hydraulic system in the industry and it would be worth poo if the engine couldn't handle the loads to allow the system to work to full effectiveness. CAT and ASV (PT100) use very close to the same system (load sensing piston pumps), but the ASV smokes all comers due to its ability to drive it's pumps better than the CAT or anyone else out there- ASV vs. CAT 4.4L vs. 3.3L, 306ft lbs vs. 217ft lbs, 92net hp vs. 90net hp. CAT=33gpm@4061psi vs ASV= 40gpm@3650psi.


The PT100 does make more torque about 18 foot pounds. What I like about the BIC system is ability to reverse flow and the ability to use other functions without derating the highflow. I am not aware of any other highflow system that does that. So although you do give up 18 foot/pounds I think the other advantages as mentioned and the remote cooler more than compensate for the power reduction. No one else even comes close to this kind of power that ASV and CASE machines can generate at the high flow.

[ksss]

The more pressure you make the less flow you will need to make the same hyd hp however as the pressure rises I am sure the pump losses efficiency.

So at 5000 psi you will need 26 gpm of flow to = 77 hyd/hp

Excavators are a much better platform for mulching due to the simple fact that virtually all of the pump flow can be directed to the attachment while cutting.
A carrier platform like a skid has to move the machine to engage the material being mulched therefore needing more engine hp to accomplish the nsame task.

To effectivley get 77 hyd/hp in a skid steer application I would think you would need close to double that in engine hp.

Those are good points. An excavator is good platform for mulching, assuming you can keep it cool. Excavators at elevation of all makes struggle to keep cool in the Summer. A mulcher would only intensify that. That is probably why many of the largest use a remote powerplant to run the attachment. A skid steer mulcher is at best a light to medium duty mulching answer. The upside atleast as I am seeing the market, most of the work fits that type job description. ROW has already cleared so if your maintaining, the sapling are relatively small. If your breaking into previously uncleared area, a dedicated tracked mulcher or excavator is certainly more productive.

I also contacted Seppi off your link. Apparently my closest dealer is in Mn. I like that head you linked to. I have not seen a price yet though. What I like about the concept is that you don't tear up the ground as bad and when you get into really rough terrain you could clear a lot more ground, no small issue where I am at. I am hoping the price is reasonable.

[YellowDogSVC]

The PT100 does make more torque about 18 foot pounds. What I like about the BIC system is ability to reverse flow and the ability to use other functions without derating the highflow. I am not aware of any other highflow system that does that. So although you do give up 18 foot/pounds I think the other advantages as mentioned and the remote cooler more than compensate for the power reduction. No one else even comes close to this kind of power that ASV and CASE machines can generate at the high flow.

and point out that the CASE, in the case of its skids, are lighter than the ASV

[YellowDogSVC]

Here are some formulas and info to read on.


http://www.hydroleduc.com/site/medias/_pdf/_en_micro_p_t_formula.pdf

http://www.surpluscenter.com/Hydraulic.htm


http://www.hydraulicspneumatics.com/200/TechZone/HydraulicPumpsM/Article/True/6428/TechZone-HydraulicPumpsM


http://www.progressivehydraulics.com/calchp.htm

good references

[Digdeep]

and point out that the CASE, in the case of its skids, are lighter than the ASV

The skids are powerhouses with those engines. ASV's PT100 is actually almost 800lbs lighter than Case's largest CTL.

[Digdeep]

The PT100 does make more torque about 18 foot pounds. What I like about the BIC system is ability to reverse flow and the ability to use other functions without derating the highflow. I am not aware of any other highflow system that does that. So although you do give up 18 foot/pounds I think the other advantages as mentioned and the remote cooler more than compensate for the power reduction. No one else even comes close to this kind of power that ASV and CASE machines can generate at the high flow.

I'm glad to see Case allowing the BIC to be factory ordered again. I never understood why they were making the dealer drop ship the machine from the factory and pay direct to Burlington.:confused:

[YellowDogSVC]

I'm glad to see Case allowing the BIC to be factory ordered again. I never understood why they were making the dealer drop ship the machine from the factory and pay direct to Burlington.:confused:

Time for Bobcat to find a similar solution. They both use gear pumps, correct? I may be looking close at a 465 series III when my 330 is ready to trade in if the new M series doesn't offer much better performance.

[ksss]

I'm glad to see Case allowing the BIC to be factory ordered again. I never understood why they were making the dealer drop ship the machine from the factory and pay direct to Burlington.:confused:


It appears to me to be a rather odd relationship between the two. I have been conversing with the BIC guys for about year. Very helpful. I sense however some competetiveness between the two. Hard to explain but its odd

What is most surprising is the relatively cheap price. A 465 with factory highflow adds about 2K to the price. The BIC system is about 5K. However you don't add the CASE factory highflow so really the difference is 3K. Add in the aux. cooler and the other functions of the BIC, I think its a pretty good deal. Especially when you consider the capacity that it gives you over the factory high flow, which is pretty good as it is.

[Ausman]

Well im proud of you guys you worked out gear pums are no comparison to variable displacement roatary piston pumps all for your selves. Also that no matter what a manufacturer writes on a peice of paper that they have set their releif to, that if you dont have the horses, you cant pull the hydraulic power. It is real easy to sit down and put numbers through a calculator but you need to get on a flow metre to see if it is possible to acheive it in real life or in fact draw the torque curves.

[ksss]

Well im proud of you guys you worked out gear pums are no comparison to variable displacement roatary piston pumps all for your selves. Also that no matter what a manufacturer writes on a peice of paper that they have set their releif to, that if you dont have the horses, you cant pull the hydraulic power. It is real easy to sit down and put numbers through a calculator but you need to get on a flow metre to see if it is possible to acheive it in real life or in fact draw the torque curves.

That is all true.