2 hydro pumps vs 1 (Cub Cadet) vs (Kubota)

[jas67]

Originally Posted by dodge man View Post
I've never had a problem with my BX2350. The only thing I've notice is some feed back in the steering wheel on occasion. Say I raise the deck and when it bottoms out and the pump goes into relief, I will feel a slight bump in the steering wheel, but no loss of power steering. *In my opinion, it is a non issue dreamed up as a sales gimmick.

If there is no benefit to two pumps, then why do all the larger Kubotas have dual pumps?

 

[mswlogo]

I never had such an issue with the BX24 but you always had to have RPMs up to do much of anything with hydraulics.

Where as the B2320 it can be at idle and all hydraulics works at nearly full speed. It so happens to have dual pumps.

 

[LBrown59]

If two pump-tractors start selling better than two pump tractors

If three pump-tractors start selling better than two pump tractors

 

[TripleR]

Funny how so many never felt the "need" for dual pumps until someone else came out with them. Sales "gimmick" or not I will be surprised if we don't start seeing them as standard.

 

[rdsaustintx]

I thought Yanmar was building the small JD's, now they are building CC's??

 

[TripleR]

I thought Yanmar was building the small JD's, now they are building CC's??

Yes, there is a current thread on this on the John Deere Forum speculating if and what the Yanmar engine will be replaced with.

 

[quarencia]

I must be strange. The number one improvement I'd make on my bx2230 is either a bigger pump or two pumps. I do a lot of heavy FEL work moving rocks and dirt around a New England hill. When I'm using the FEL near it's limits, the PS fades. Not a little either. It can disappear. If I max the hydraulics with the loader and the pressure relief valve opens, the PS is gone. Many times I will have to back out and approach a load differently because I can't turn and load at the same time effectively. And before I'm asked, I've checked both the pressure and flow on my tractor. They're within spec.

If you're going to routinely put heavy demands on the hydraulic system, two pumps can make a difference.

That being said, I don't think I'd let one or two pumps be the sole decision maker between Kubota and Cub Cadet, but it would be a factor for me.

 

[rScotty]

I must be strange. The number one improvement I'd make on my bx2230 is either a bigger pump or two pumps......snip...

If you're going to routinely put heavy demands on the hydraulic system, two pumps can make a difference.

That being said, I don't think I'd let one or two pumps be the sole decision maker between Kubota and Cub Cadet, but it would be a factor for me.

I think the advantage of two pumps is that way they can each pump on completely separate circuits. No crossover.

JD solved the problem of one circuit scavanging flow from another by going to a closed center hydraulic system which then allows a variable displacement pump and a pressure storage vessel called an accumulator. Has anyone here ever tried that? Is that attractive?
rScotty

 

[LBrown59]

I thought Yanmar was building the small JD's, now they are building CC's??

Yanmar was building 1 tractor with green and yellow paint and sticking JD labels on them.
Today they are they are building 1 tractor and are painting some of them green and yellow and putting JD labels on them and painting the rest of them yellow and black and sticking CC labels on them .

 

[JOHNTHOMAS]

Yanmar was building 1 tractor with green and yellow paint and sticking JD labels on them.
Today they are they are building 1 tractor and are painting some of them green and yellow and putting JD labels on them and painting the rest of them yellow and black and sticking CC labels on them .

Now this is what I like seeing from you LB. An understandable informative answer. Much better than Me to. OK. 1...2...3...I've got 2 or I've got 3. You've messed up...now we know you can do it.

 

[quarencia]

Actually...Cub Cadet is Yanmar and Yanmar is Cub Cadet, at least for new tractors. They formed a Joint Venture called C.U.T. Supply. That was over two years ago. Link to press release

Looked up the SC2400 Yanmar/Cub Cadet to see what they say about the dual pumps. They have a gear pump operating at 3.6 GPM for PS, FEL, and 3p. The second pump is a trochoid pushing 3.5 GPM for PTO Clutch and HST charge. Didn't see pressure info, but trochoids are like automotive oil pumps. Can't see what this arrangement really does for you. If I recall correctly, trochoids aren't good for generating very high pressures. Perhaps there is an efficiency gain from using this pump. But I really don't see the advantage that an operator would ever notice. With the PS and work ports on the same circuit, there doesn't appear to be a big advantage. I suppose if you don't have to regulate the high pressure back down to lower pressure before it gets to PTO clutch and HST charge, you're removing a heat source from the loop, but the complexity of the second pump and plumbing seems to negate that advantage.

 

[Volfandt]

Looked up the SC2400 Yanmar/Cub Cadet to see what they say about the dual pumps. They have a gear pump operating at 3.6 GPM for PS, FEL, and 3p. The second pump is a trochoid pushing 3.5 GPM for PTO Clutch and HST charge. Didn't see pressure info, but trochoids are like automotive oil pumps. Can't see what this arrangement really does for you.

quarencia, I cut your quote down to save space otherwise it's unaltered and I totally agree with you.

The BX's use a priority valve to "split" the implements hydraulic pump output between the PS and the rest of the implement controls. In this way even when the FEL or 3ph is lifting a max load there is still some hydraulic power available for the PS to function. In a tractor the size of a SCUT this is perfectly acceptable. I personally have only run into one occasion where the PS seemed to be temporarily robbed of power when I was doing some very strenuos FEL work leveling a gravel driveway but it was only for a sec or so and it didn;t detract from the work.

With the info provided by quarencia, it appears that the Cub/Yanmar has to use a similar priority valve type setup. and if so theres no advantage.......

Marketing can be an amazing thing

 

[LBrown59]

It would take more than an extra pump to make a CC superior to a Kubota.

 

[N80]

I don't know anything about SCUT's and very little about the larger Kubotas with 2 pumps, but I do have a 45 HP CUT with one pump. There has never been any evidence or symptom of a problem related to that pump also running the power steering. There have been times when a larger GPM pump might be handy but that has nothing to do with how many pumps there are. So as far as I am concerned, any salesman that hyped any tractor because it had an additional pump, the first thing I'd ask was what was wrong with the first one!

But, as others have mentioned, as soon as it becomes market lingo, others will follow whether there is a benefit or not. As far as I am concerned, it just sounds like one more extra to pay for and one more thing to break.