Hydraulic, Horsepower and CUTS

woodlandfarms · Dec 8, 2006

Just about the time I finally figured out CUT's is when I decided they were not for me and I needed something more slope friendly. So I apologize if these are simple questions in advance, but I am trying to wrap my head around a Hydraulic machine...

We were discussing chippers and making a hyd motor driven machine. Some math came my way via JJ I think

"The PT 422 and 425 are rated at 8 GPM at 2500 PSI = 20,000 somethings. Divide that by 1500 and you get 13.3 horsepower. 13.3 * .85 = 11.33."

So, in looking at the 1430.... 12gpm @ 2500PSI = 30,000 / 1500 = 20hp or around 17hp.

So, my questions are this. Is the 1430 only really putting 17hp to the ground? This seems like not enough considering the weight of the machine. Brush Hogs at 5' seem to require around 22HP with a CUT PTO. a 5' rota tiller is also around 22HP. How does this thing pull a box-blade around at 17HP? If I rig a motor to the Hydraulics to drive a chipper, lets say that the chipper is rated 17 to 40 HP PTO (jinma 6 for example) can this PT tractor do that?

None of this is an attack on the tractor, everyone here loves (and hates) there machine, and most of you seem quite stable ;-). So i trust that this machine will perform as advertised. It is just that it took me forever to understand how much a 35hp CUT could and could not do, so I am trying to figure out how to equate the difference, to see if I should pony up for the 1845.

Thanks for taking the time to read this

Carl

Bob999 · Dec 8, 2006

woodlandfarms said:
Just about the time I finally figured out CUT's is when I decided they were not for me and I needed something more slope friendly. So I apologize if these are simple questions in advance, but I am trying to wrap my head around a Hydraulic machine...

We were discussing chippers and making a hyd motor driven machine. Some math came my way via JJ I think

"The PT 422 and 425 are rated at 8 GPM at 2500 PSI = 20,000 somethings. Divide that by 1500 and you get 13.3 horsepower. 13.3 * .85 = 11.33."

So, in looking at the 1430.... 12gpm @ 2500PSI = 30,000 / 1500 = 20hp or around 17hp.

So, my questions are this. Is the 1430 only really putting 17hp to the ground? This seems like not enough considering the weight of the machine. Brush Hogs at 5' seem to require around 22HP with a CUT PTO. a 5' rota tiller is also around 22HP. How does this thing pull a box-blade around at 17HP? If I rig a motor to the Hydraulics to drive a chipper, lets say that the chipper is rated 17 to 40 HP PTO (jinma 6 for example) can this PT tractor do that?

None of this is an attack on the tractor, everyone here loves (and hates) there machine, and most of you seem quite stable ;-). So i trust that this machine will perform as advertised. It is just that it took me forever to understand how much a 35hp CUT could and could not do, so I am trying to figure out how to equate the difference, to see if I should pony up for the 1845.

Thanks for taking the time to read this

Carl

A PT has three hydraulic pumps--one is a variable displacement pump that drives the wheels. The max pressure and flow of this pump is not published but I suspect that it is designed to take about half the 30 hp that the engine of the 1430 is rated for. My assumption about the power is based on the fact that with the PTO in use driving a mower I can bog the engine down going up a steep hill unless I "use a low gear" (push the treadle down only a little).

A second pump is a gear pump for the PTO and that is the pump you are doing the calculations for. The third pump is a small gear pump that drives the lift cylinders, and steering.

All three pumps are driven all the time. However the load on any pump varies depending on the task the tractor is doing. When running a chipper typically neither the lift/steering pump or the variable displacement pump would have much load (because the tractor is sitting still) and there would be no problem getting the full rated output of the PTO circuit because most of the 30 engine hp would be available to drive the PTO pump.

As a practical matter the maximum load occurs with a major PTO load--like a mower--combined with moving up a steep hill. In this case both the PTO pump and the variable displacement pump are called upon for large amounts of power.

BobRip · Dec 8, 2006

woodlandfarms said:
Just about the time I finally figured out CUT's is when I decided they were not for me and I needed something more slope friendly. So I apologize if these are simple questions in advance, but I am trying to wrap my head around a Hydraulic machine...

We were discussing chippers and making a hyd motor driven machine. Some math came my way via JJ I think

"The PT 422 and 425 are rated at 8 GPM at 2500 PSI = 20,000 somethings. Divide that by 1500 and you get 13.3 horsepower. 13.3 * .85 = 11.33."

So, in looking at the 1430.... 12gpm @ 2500PSI = 30,000 / 1500 = 20hp or around 17hp.

So, my questions are this. Is the 1430 only really putting 17hp to the ground? This seems like not enough considering the weight of the machine. Brush Hogs at 5' seem to require around 22HP with a CUT PTO. a 5' rota tiller is also around 22HP. How does this thing pull a box-blade around at 17HP? If I rig a motor to the Hydraulics to drive a chipper, lets say that the chipper is rated 17 to 40 HP PTO (jinma 6 for example) can this PT tractor do that?

None of this is an attack on the tractor, everyone here loves (and hates) there machine, and most of you seem quite stable ;-). So i trust that this machine will perform as advertised. It is just that it took me forever to understand how much a 35hp CUT could and could not do, so I am trying to figure out how to equate the difference, to see if I should pony up for the 1845.

Thanks for taking the time to read this

Carl

Carl, I am sorry to have created the confusion. The PT422 PTO pump is rated at 8 GPM at 2500 PSI. The PT422 has 4 pumps I think as do the other PTs. There are two wheel motor pumps and one for steering, lift and tilt. I don't know the ratings of these. They will fully utilize the capacity of the engine. I would bet my 422 against any riding mower that has a 22 HP engine. I tried to do this comparison to the PT and CUTs when I had a 15 horse power diesel CUT. I sold the CUT right after I got the PT and have never missed it. The PT runs rings around the CUT. I wanted to get a bucket for the CUT and it was about 2500. The same bucket for the PT was $300. One day I moved one of the CUT attachments on a hand truck because that was easier than attaching it and moving it. I found that I would put the mower on in the spring and the snow blade on in the fall because it was such a pain to swap. On the PT I will swap attachments 2 or 3 times a day on a slow day and many times a day if needed. Ask us what you plan to do with the machine and we will comment on that.

The PT also stands out in manueverabilty. My neighbor and I moved and spread 20 tons of top soil in 1.5 hours with the 422. Try that with a CUT.

Mowing - I find when the grass gets to high I just slow down a little to ease the mowing load. It's easy to do. If mowing is your main or only task, the PT may not be the best choice. However I like to see what I am mowing and that is a strong point for the PT. What kind of mowing are you doing? I mostly use it for clearing trails through the woods and mowing along the road and rough ground.

woodlandfarms · Dec 8, 2006

BobRip said:
Mowing - I find when the grass gets to high I just slow down a little to ease the mowing load. It's easy to do. If mowing is your main or only task, the PT may not be the best choice. However I like to see what I am mowing and that is a strong point for the PT. What kind of mowing are you doing? I mostly use it for clearing trails through the woods and mowing along the road and rough ground.

Bob

We have 40 acres of rolling to severe rolling blackberries and brush and lots of pines and alders. Brushhogging is the top on my list, with road maintenance (1 mile of dirt road) a close second. We plan to install greenhouses on the slopes, so moving dirt, creating roads, and trenching are high on my list. Eventually we will rotatill a couple of acres, but that is at least 3 years off. We will begin new house construction sometime in 2009... FEL work is important, and the brush attachment will be a must. Brushogging will some day be less, but 40 acres in the pacific north west I think it may be more constant than I want.

I just realized I was not looking at the full lineup, and bypassing the 1445... It is still 4K out of my budget, but not nearly the 8K that the slope mower is. And I am now not so sure that the slope mower is all that important. It has been suggested that my 27 degree property is just fine with the 1430/45.

We are waiting on pins and needles to find out if we got another project (tv commercial) to produce. If it happens, I have my tractor money... Now I just need a building to put it in and not the open shed we have... I really need to stop spending money....

Carl

ptx · Dec 8, 2006

Hi,

We are in Washington also and considering a PT 418 or 422.

Anyone in Washington have one we can look at before we order ?

thanks
ptx

BobRip · Dec 8, 2006

Woodsland, given the diversity of your needs, the Power Trac is probably a good choice, but your property size is well outside my experience as I have only 10 acres. Hopefully someone else will comment. The 422 is very adequate for my 10 acres and I help with occasional projects at other properties. If I were chosing again I would pick the 425 for the extra wheel motor torque and horsepower for my applications of bush hoggin, trenching, 300 foot driveway maintenace, garden soon. Others please jump in here with your experience and comments.

MossRoad · Dec 9, 2006

woodlandfarms said:
Just about the time I finally figured out CUT's is when I decided they were not for me and I needed something more slope friendly. So I apologize if these are simple questions in advance, but I am trying to wrap my head around a Hydraulic machine...

We were discussing chippers and making a hyd motor driven machine. Some math came my way via JJ I think

"The PT 422 and 425 are rated at 8 GPM at 2500 PSI = 20,000 somethings. Divide that by 1500 and you get 13.3 horsepower. 13.3 * .85 = 11.33."

So, in looking at the 1430.... 12gpm @ 2500PSI = 30,000 / 1500 = 20hp or around 17hp.

So, my questions are this. Is the 1430 only really putting 17hp to the ground? This seems like not enough considering the weight of the machine. Brush Hogs at 5' seem to require around 22HP with a CUT PTO. a 5' rota tiller is also around 22HP. How does this thing pull a box-blade around at 17HP? If I rig a motor to the Hydraulics to drive a chipper, lets say that the chipper is rated 17 to 40 HP PTO (jinma 6 for example) can this PT tractor do that?

None of this is an attack on the tractor, everyone here loves (and hates) there machine, and most of you seem quite stable ;-). So i trust that this machine will perform as advertised. It is just that it took me forever to understand how much a 35hp CUT could and could not do, so I am trying to figure out how to equate the difference, to see if I should pony up for the 1845.

Thanks for taking the time to read this

Carl

Our PT425 with its 8GPM PTO pump at 2500PSI runs a 4' brush cutter that destroys everything in its path that can be knocked over. 1" hardwoods are nothing. 2" hardwoods make a lot of noise, but end up trail mulch if I can push them over with the brush hog. This is only a 1500 pound machine and the front lip of the brush hog is only 6" off the ground. So if you can imagine pushing over 2" trees only 6" above the ground with a mower deck, that takes a lot of leverage.

I'm pretty sure the 1430 with its 5' brush hog would destroy most of what you described on your property.

I don't have a tiller, so I can't comment on that.

RegL · Dec 9, 2006

" I'm pretty sure the 1430 with its 5' brush hog would destroy most of what you described on your property. "

I will attest to that. And don't let anyone stand within 200 ft when your in those hardwoods.

pajoube · Dec 9, 2006

ptx said:
Hi,

We are in Washington also and considering a PT 418 or 422.

Anyone in Washington have one we can look at before we order ?

thanks
ptx

take a look at my post PowerTrac Owners by State #8, which will give you by owner and type of PowerTrac. Then by using their TractorbyNet signature you can contact them and arrange to view and test drive.
PJ

woodlandfarms · Dec 10, 2006

RegL said:
" I'm pretty sure the 1430 with its 5' brush hog would destroy most of what you described on your property. "

I will attest to that. And don't let anyone stand within 200 ft when your in those hardwoods.

I think this is to all... so why does the hog not have chains hanging on it like others? I here that helps deflecting debris...