How big of a pump can I drive with this:

[Borisw37]

I am totally new to the hydraulics world but do have an engineering background.
So the question is, how big of a pump can I drive with a 600cc motorcycle engine (~100hp). Here is a link to the dyno chart HP/RPM/Torque
2005 Honda CBR 600 RR Dyno Results Graphs Hosepower - DragTimes.com

The pump need to generate standard 3000psi max, will be used to drive hydraulic motors down the line.

I know that a high RPM, low torque engine is not optimal but that's what I have for now.
If somebody could explain how the max pump GPM is calculated that would be great.

Thank you,

Boris

 

[bkc]

I am not a hydraulics pro either...... but the biggest problem i can see is the RPM of the engine.
most pumps spin at 2000 rpm or 3600 rpm for use with lawn mower type engines.
Somthing to consider.

Brian

 

[Borisw37]

I am not a hydraulics pro either...... but the biggest problem i can see is the RPM of the engine.
most pumps spin at 2000 rpm or 3600 rpm for use with lawn mower type engines.
Somthing to consider.

Brian

Since its a motorcycle engine I have the luxury of a 6speed transmission and by adjusting the output sprocket ratio I can gear down the RPM to the necessary 2000 or 3600. So for example if I want the engine to run at 9500RPM and pump at 3600 I'll need ~2.6 reduction. The transmission has a 2:1 primary reduction, 1.377 reduction in 4th gear so I'll end up with ~2.7 reduction w/out using the final drive sprocket reduction.

 

[oldnslo]

I am totally new to the hydraulics world but do have an engineering background.
So the question is, how big of a pump can I drive with a 600cc motorcycle engine (~100hp). Here is a link to the dyno chart HP/RPM/Torque
2005 Honda CBR 600 RR Dyno Results Graphs Hosepower - DragTimes.com

The pump need to generate standard 3000psi max, will be used to drive hydraulic motors down the line.

I know that a high RPM, low torque engine is not optimal but that's what I have for now.
If somebody could explain how the max pump GPM is calculated that would be great.

Thank you,

Boris

GPM x PSI divided by 1500 will give you rough input HP needed.

Or rough rule of thumb 1 HP will produce 1 GPM at 1500 PSI so if you have 100 HP you could produce around 50 GPM @ 3000 PSI.

Roy

 

[Borisw37]

Thanks for the info. I have looked at a number of "HP requirement calculators" (Hydraulic)
And what I get is 40GPM@3000 PSI = 82HP
What I don't fully understand is the engine torque vs rpm vs HP.
Does it all just boil down to HP and torque is just how I gear the output? Basically is there any difference between using a
1) 100HP motor with direct output of 3600 rpm
vs
2) 100HP motor with 10,800 rpm, geared down 3:1

Besides the obvious power loss in the transmission (lets say 5-10% loss) Sports Engineering, Volume 7, Number 2 - SpringerLink

 

[bigdeano]

This is a little off the topic of your post, but you may have a problem with overheating if you use the stock radiator for this engine. Motorcycles depend on high speed ram air for cooling when they're putting out a lot of horsepower.

I used a Honda CX500 engine on my homemade garden tractor. I used the stock radiator with an electric fan. I can't keep it from overheating, and I'm only using about 20 hp. I even added a heater core as a second radiator with an electric fan. No luck.

You might want to plan on a car radiator to be safe. Just something to think about.

 

[J_J]

Thanks for the info. I have looked at a number of "HP requirement calculators" (Hydraulic)
And what I get is 40GPM@3000 PSI = 82HP
What I don't fully understand is the engine torque vs rpm vs HP.
Does it all just boil down to HP and torque is just how I gear the output? Basically is there any difference between using a
1) 100HP motor with direct output of 3600 rpm
vs
2) 100HP motor with 10,800 rpm, geared down 3:1

Besides the obvious power loss in the transmission (lets say 5-10% loss) Sports Engineering, Volume 7, Number 2 - SpringerLink

Your 100 HP engine can possible drive a 48 GPM pump at 3000 psi.

I don't think you can run that engine at that rpm very long to develop that HP.

Even if you gear it down, the engine is still working to hard at max rpm.

 

[CJONE]

You only have about 50 electric brake horsepower and along with the overheating problem you will have, you will have a terrible time trying to control rpm verses load on a engine like that. Gas engines are about 1/2 EBH vs rating. Diesel is about 2/3 EBH. The torque is low on gas engines. So at best you can get 50 GPM at 1500 psi or 25 at 3000psi. Just a guess if you could control the throttle/RPM the engine would not last long at max HP and steady max RPM. CJ

 

[dfkrug]

This is a little off the topic of your post, but you may have a problem with overheating if you use the stock radiator for this engine. Motorcycles depend on high speed ram air for cooling when they're putting out a lot of horsepower.

I used a Honda CX500 engine on my homemade garden tractor. I used the stock radiator with an electric fan. I can't keep it from overheating, and I'm only using about 20 hp. I even added a heater core as a second radiator with an electric fan. No luck.

You might want to plan on a car radiator to be safe. Just something to think about.

Interesting.

I ran my CADDigger 728's pump initially off a Yamaha 750 4-cyl air-cooled engine. The pump was
a small Barnes pump (0.194ci if I recall), specced for 3600 RPM. I loved the smoothness and how
quiet it was. The shaft drive output made it easy to link to the pump as well. The trick is to use these
engines way below their peak power output, and even then, they can overheat. I ran mechanical
and electric fans, but the oil temp went up and up. I eventually gave up and went to a 10hp
Tecumseh.

I since got a CX500 engine, and I plan to run a pump with that, but I always thought I would need
an automotive radiator and fan. The OEM rad is TINY. I long since got rid of the CADDigger, however.

At least the OP's engine is water-cooled. That's key. I would run a larger displacement pump slower
and use a big rad. You can get good work out of these engines at only 3500-4K RPM.

 

[CJONE]

Interesting.

I ran my CADDigger 728's pump initially off a Yamaha 750 4-cyl air-cooled engine. The pump was
a small Barnes pump (0.194ci if I recall), specced for 3600 RPM. I loved the smoothness and how
quiet it was. The shaft drive output made it easy to link to the pump as well. The trick is to use these
engines way below their peak power output, and even then, they can overheat. I ran mechanical
and electric fans, but the oil temp went up and up. I eventually gave up and went to a 10hp
Tecumseh.

I since got a CX500 engine, and I plan to run a pump with that, but I always thought I would need
an automotive radiator and fan. The OEM rad is TINY. I long since got rid of the CADDigger, however.

At least the OP's engine is water-cooled. That's key. I would run a larger displacement pump slower
and use a big rad. You can get good work out of these engines at only 3500-4K RPM.

If you are correct on displacement then you had 3 gpm of flow at 4K at 2000psi that would be about 4 hp.
I could see that engine doing that without much trouble. But 25 or 30 GPM at 2k. and have something
useable I think will not be viable. CJ