16 GPM vs 22 GPM??

[blackdiesel]

Buddy of mine had an old brave 30 ton splitter. after a little research i "think" it had a 16 gpm pump on it (8 hp b&s) Well the motor was using ALOT of oil and he was helping me out with a seasoned cord or two, so i slapped my 11 hp honda and 22 gpm pump on the splitter. Now i never ran it before i swithced the motors but the owner said there wasnt a change in the cycle time? and it did seem really slow to me.

i had to put a bigger fitting in the suction side in order to hook it up to the pump. also had to put a new 3/4 pressure hose on it. which used to be 1/2. The fluid gets hot fast but the cycle time hasnt improved? what gives?

 

[Haywire Haywood]

I'm guessing, but low flow control valve?

Also, are you running the engine at full throttle? More RPM= More Flow

Ian

 

[blackdiesel]

I'm guessing, but low flow control valve?

Also, are you running the engine at full throttle? More RPM= More Flow

Ian

i was leaning towards the valve. which one does it need on it

im running the motor at whatever twolf set up for to run a processor. i only started it up and cycled it a couple times when i first put it on. He, on the other hand, has split 6 or 8 cords with it

 

[Wood Doctor]

I use a Barnes 16 gpm 2-stage pump, a 6.5 Hp slant-eye engine, a 3" dia. cylinder with a 26" throw, and my cycle time is less than 7 seconds. I don't even need automatic return, and this splitter seldom if ever stalls out.

'nuff said.

 

[blackdiesel]

I use a Barnes 16 gpm 2-stage pump, a 6.5 Hp slant-eye engine, a 3" dia. cylinder with a 26" throw, and my cycle time is less than 7 seconds. I don't even need automatic return, and this splitter seldom if ever stalls out.

'nuff said.

awesome. my processor has a cycle time that comes in at 5 seconds with an 8 way splitter and has another stick cut ready to split by the time the cylinder returns.... however neither your story or mine fixes this other guys wood splitter.

 

[Wood Doctor]

awesome. my processor has a cycle time that comes in at 5 seconds with an 8 way splitter and has another stick cut ready to split by the time the cylinder returns.... however neither your story or mine fixes this other guys wood splitter.

Yes, I know that. However, I thought I would throw that in. Many trimes we buy splitters with huge cylinders and larger pumps for more splitting power. We often forget that when you double the cylinder diameter with the same stroke, it takes 4 times the pump capacity to maintain the same cycle time. Going from 16 gpm to 22 doesn't mean much with big cylinders to fill.

 

[blackdiesel]

Yes, I know that. However, I thought I would throw that in. Many trimes we buy splitters with huge cylinders and larger pumps for more splitting power. We often forget that when you double the cylinder diameter with the same stroke, it takes 4 times the pump capacity to maintain the same cycle time. Going from 16 gpm to 22 doesn't mean much with big cylinders to fill.

so your saying the extra 6 gpm wouldnt help a bit if there wasnt a bottleneck @ the valve???

 

[Wood Doctor]

so your saying the extra 6 gpm wouldnt help a bit if there wasnt a bottleneck @ the valve???

It would help a little, but any problems with the valve would not be overcome by a bigger pump. If the valve is indeed the problem and fixed, you will pick up tremendous speed in the cycle time. Bumping the pump capacity will help drop the cycle time, but not like a valve repair/changeout job.

 

[blackdiesel]

It would help a little, but any problems with the valve would not be overcome by a bigger pump. If the valve is indeed the problem and fixed, you will pick up tremendous speed in the cycle time. Bumping the pump capacity will help drop the cycle time, but not like a valve repair/changeout job.

?????

I did not put the bigger motor/pump on this splitter to increase cycle time. i put it on there because its what i had. however speed should be a by-product from this upgrade. right now it is not. my question was why does this splitter not cycle faster than it used to? not an explination that a bigger cylinder with a bigger pump wont increase cycle time...

 

[Ductape]

A valve made to flow 5 gpm will only FLOW 5 gpm. Same with small hoses and fittings. Increasing pump size will force you to increase the size of many other components.

 

[AKKAMAAN]

Ductape:
A valve made to flow 5 gpm will only FLOW 5 gpm. Same with small hoses and fittings. Increasing pump size will force you to increase the size of many other components.

If the valve is rated "5gpm" and a pump provides 10gpm (a certain displacement at a certain rpm), the valve will always let the 10gpm thru, unless part of flow get by passed. By pass can be in RV due to excessive pressure, or in the the valve, if valve have internal leak or if valve have a partially open center at the moment.

To make sure the whole pump flow get to work port, one must give spool in the valve full stroke (lever to the end). Many valves will divert oil to tank thru open center almost thru the whole valve stroke.

Again, part of flow displaced by pump, can not just dissapear, unless part of flow is by passed in RV or valve.

So in this case, comparing these two pumps 16gpm vs 22 gpm, we first have to make sure their ratings are set at the same rpm and also that they are running at the same rpm and have the same internal leakage, and no part of flow is by passed. Of course we also have to use the same size of cylinder, bore, rod and stroke.

If these conditions are met, the 22gpm pump must come out (22-16)/16=37.5% faster than the 16 gpm pump, what ever the valve rating is.

If we use the same valve on both pumps we will probobly have a slightly increased "supply" pressure before the valve with the 22gpm pump. That will, theoretically, increase internal leakage a little....1%??...but not enough to make the two pumps equal in performance....unless the 22gpm pump is severly worned out.

 

[sawinredneck]

You can only flow oil as fast as the smallest part of the system will allow you to.
To save a buck most splitters are built with hoses that are close to max capacity already. An 11gpm unit will have 1/2" fitting max. a 16gpm unit will have 5/8" fittings and so on and everything is rated for that flow.
While it is theoreticly possible to flow more fluid through the same hole, it creates a lot of heat and friction, you get a lot of these bottlenecks and they start to add up quickly also.
The hoses are maxed out, the valve is maxed out and the return system, including filter is maxed out, lots of things to create heat and hold you up.
Quick and easy thing, when was the last time the filter was changed? It might have worked fine with the old pump, but now it can't flow the extra fluid? Just an idea.

 

[Haywire Haywood]

Quick and easy thing, when was the last time the filter was changed? It might have worked fine with the old pump, but now it can't flow the extra fluid? Just an idea.

If the filter was clogged, you might never know it. My filter housing has a bypass valve in it. If the return gets over 15psi, it opens and bypasses the filter entirely. If it didn't have a bypass, your first indication of a clogged filter would be a ruptured filter. They aren't made to take much pressure.

Ian

 

[AKKAMAAN]

Yes, I know that. However, I thought I would throw that in. Many trimes we buy splitters with huge cylinders and larger pumps for more splitting power. We often forget that when you double the cylinder diameter with the same stroke, it takes 4 times the pump capacity to maintain the same cycle time. Going from 16 gpm to 22 doesn't mean much with big cylinders to fill.

I agree with Wood Doctor here. 22gpm is 37.5% more than 16gpm.....that is significant if it is to the same size cylinder.....If you you at the same time increase bore diameter.....the larger pump might even make it slower...
See my table below...
This is the cycle time that must come out if....

• Pump is rated correct
• Pump stays in high flow/low pressure stage
• No restriction on suction side of pump
• No internal leakage
• No flow by passed by relief valve
• "Open center" valve have FULLY closed center at operation