One major advantage of the belt setup is the ability to tune the pump speed and engine speeds to operate optimally. This allows the same engine to run a slightly larger pump effectively. For example, consider little GX270 pulling a Cat 66DX at rated power. With a 3.5gpm pump, it can hit 4000psi. With a 4gpm, it can only hit about 3200psi. With a 5gpm, it's limited to about 2250psi. And if you try to run much higher pressures than those values with those three pumps, you'll pull down the engine speed and reduce flow to where the smaller pump would actually outperform. The 5gpm CAT is rated 3250 prpm, the smaller pumps are 3400prpm for rated speed. If I ran a belt setup setup on the GX270 to drive the 5gpm pump at 2750rpm while the engine was at 3600, I multiply the engine's torque output by 30%. This will push the 5gpm pump to 3000psi, but at the reduced flow of 4.25gpm. A minor improvement over the 4gpm pump, but still an improvement. But the real advantage is the ability to target a peak pressure range (torque) and optimize flow for that. Say your sweet spot is 2500psi. Cat says that at this pressure the 5gpm DX66 needs 13.8lb-ft. Which means the 12.8lb-ft of the GX270 needs another 10% more torque, roughly. So you setup your GX270 on a 10% underdrive and get 14lb-ft to the pump at 3240pump rpm. The pump's rated speed is 3250rpm. Presto, you have a 5gpm setup with usefully sufficient pressure (2500psi) running off a GX270! Remember, you can reduce pressure with a larger nozzle orifice, but you cannot increase flow. A belt setup lets you tune the drive ratio (via pulley sizes and belt length). So if you are running a setup that is capable of 4000psi, you are wasting engine power to hit a potential pressure range you almost certainly don't need. And you are giving up GPM that you actually DO need to get it! That's not a good tradeoff. Not all "cleaning units" are the same. Once you have enough pressure, you have enough pressure. More pressure won't clean more effectively or faster. Flow will. I'd suggest therefore that you consider something like 3000psi to be a hard ceiling of capability you do not want. Get all the flow you can that still lets you pull 3000psi. Or 2500, or whatever your personal experience suggests is the most pressure you need.
That was a very well thought out comment, thank you for the explanation. I'm new to engines, water pumps etc. but I do have years of experience in telecoms and I can easily follow what your saying referring back to (frequency, DBvm, SNR and voltage, if that makes sense) I bought a GX390 3400rpm with a 4gpm 4200psi direct drive triplex triple A pump. I would like to upgrade the pump to 5-8gpm's with an external bypass as the triple A does not have one. (I rushed the order process without doing all my homework!) Do you have any recommendations on pumps that would be optimal for that engine? Also, can I remove that pump and replace with a belt drive system or a gearbox system? I'm assuming the shaft from the engine is the same for all 3? Thank you again!
The problem with the direct drive is RPM's. If the pump max rpm is 3500 and the 14hp engine runs at 5000 rpm's it will kill the pump. That's why a 2 for 1 gear reduction box is so important.
I just installed the General Pump EZ4040G on my Honda GX390 and when I pull & let go of the trigger the seems to want to cut out. What PSI is the pump rated?
Thanks for post - if possible could you create a tutorial video setting up (external/12V) pump, and fittings to pressure washer? finding proper fittings seems to be most issue from 1/2 to 3/4
Keep it on a ball valve. Disconnect gun and open it all the way. It won’t have much pressure and you’ll continuously move water while engine is running
Instead of adding a 20ft hose and running it into a tank could you disconnect one end of that looping hose and let the water run out on the ground? If so, wouldn't the water coming in from the garden hose or tank run out where you disconnected the hose? You didn't mention what to do there. Should there be a plug to put in place of where the hose was? I'm new to this and I have a direct drive pw with a pump that looks like that one. I want my pump to last as long as possible. 🙂 Thanks for your feedback in advance.
@@mrsparklewindowcleaning679first u have to install a 1" bulkhead fitting and a 1" pvc ball valve with a 1" threaded hose barb at the bottom of ur water supply tank..then all u have to do is raise up & mount your water supply tank atleast 2-4 inches above/higher than ur pressure washer pump water supply inlet is...! (U have to make sure that ur bulkhead fitting on the bottom of ur water tank is atleast 2-4 inches higher than ur pressure washers garden hose inlet) Then hookup some 1" non-collapsible hose from ur water tank to ur pressure washer... hope this helps u.
You seem to be confusing "direct drive" with positive displacement pump (the pump type in your video), in your tutorial. The drive input does not determine what kind of pump it is, only what type of input it has. The drive input has little to do with whether a pump will gravity draw its water, that's determined by your pump/tank set up. I've had experience with both Direct drive and centrifugal pumps for almost 30 years, using hundreds of pumps and have NEVER had a pump not draw from a tank because I understand how gravity works.
Correct- there's even hydraulic driven pumps that can take a generic hydro pto/remote power supply. Can't imagine I'd really want that in a normal situation, but I can come up with some usecases.
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One major advantage of the belt setup is the ability to tune the pump speed and engine speeds to operate optimally. This allows the same engine to run a slightly larger pump effectively.
For example, consider little GX270 pulling a Cat 66DX at rated power. With a 3.5gpm pump, it can hit 4000psi. With a 4gpm, it can only hit about 3200psi. With a 5gpm, it's limited to about 2250psi. And if you try to run much higher pressures than those values with those three pumps, you'll pull down the engine speed and reduce flow to where the smaller pump would actually outperform.
The 5gpm CAT is rated 3250 prpm, the smaller pumps are 3400prpm for rated speed. If I ran a belt setup setup on the GX270 to drive the 5gpm pump at 2750rpm while the engine was at 3600, I multiply the engine's torque output by 30%. This will push the 5gpm pump to 3000psi, but at the reduced flow of 4.25gpm. A minor improvement over the 4gpm pump, but still an improvement.
But the real advantage is the ability to target a peak pressure range (torque) and optimize flow for that. Say your sweet spot is 2500psi. Cat says that at this pressure the 5gpm DX66 needs 13.8lb-ft. Which means the 12.8lb-ft of the GX270 needs another 10% more torque, roughly. So you setup your GX270 on a 10% underdrive and get 14lb-ft to the pump at 3240pump rpm. The pump's rated speed is 3250rpm.
Presto, you have a 5gpm setup with usefully sufficient pressure (2500psi) running off a GX270! Remember, you can reduce pressure with a larger nozzle orifice, but you cannot increase flow. A belt setup lets you tune the drive ratio (via pulley sizes and belt length).
So if you are running a setup that is capable of 4000psi, you are wasting engine power to hit a potential pressure range you almost certainly don't need. And you are giving up GPM that you actually DO need to get it! That's not a good tradeoff.
Not all "cleaning units" are the same. Once you have enough pressure, you have enough pressure. More pressure won't clean more effectively or faster. Flow will. I'd suggest therefore that you consider something like 3000psi to be a hard ceiling of capability you do not want. Get all the flow you can that still lets you pull 3000psi. Or 2500, or whatever your personal experience suggests is the most pressure you need.
That was a very well thought out comment, thank you for the explanation. I'm new to engines, water pumps etc. but I do have years of experience in telecoms and I can easily follow what your saying referring back to (frequency, DBvm, SNR and voltage, if that makes sense) I bought a GX390 3400rpm with a 4gpm 4200psi direct drive triplex triple A pump. I would like to upgrade the pump to 5-8gpm's with an external bypass as the triple A does not have one. (I rushed the order process without doing all my homework!) Do you have any recommendations on pumps that would be optimal for that engine? Also, can I remove that pump and replace with a belt drive system or a gearbox system? I'm assuming the shaft from the engine is the same for all 3? Thank you again!
This is exactly what I needed. Thank you
The problem with the direct drive is RPM's. If the pump max rpm is 3500 and the 14hp engine runs at 5000 rpm's it will kill the pump. That's why a 2 for 1 gear reduction box is so important.
I just installed the General Pump EZ4040G on my Honda GX390 and when I pull & let go of the trigger the seems to want to cut out. What PSI is the pump rated?
Thank you Sir for this useful information
Thanks for post - if possible could you create a tutorial video setting up (external/12V) pump, and fittings to pressure washer? finding proper fittings seems to be most issue from 1/2 to 3/4
Once you go to commercial grade, very hard to ever go back to regular.
Great vid Ray!
How much does that exact pressure washer cost?
My maintenance personnel adviced that I should just tie the trigger permanently, to save my pump, and off engine at any slight stop.
That's not the worst idea in terms of keeping pumps alive. But it might be not so great from a safety perspective.
Keep it on a ball valve. Disconnect gun and open it all the way. It won’t have much pressure and you’ll continuously move water while engine is running
Instead of adding a 20ft hose and running it into a tank could you disconnect one end of that looping hose and let the water run out on the ground? If so, wouldn't the water coming in from the garden hose or tank run out where you disconnected the hose? You didn't mention what to do there. Should there be a plug to put in place of where the hose was? I'm new to this and I have a direct drive pw with a pump that looks like that one. I want my pump to last as long as possible. 🙂 Thanks for your feedback in advance.
If you have an unloader that has an open port for bypass, you can absolutely vent that water anywhere you want. If you're willing to waste it.
That is one thing I got right, belt.
Not true, I’ve made several different direct drive pull from a tank no problem, you just have to know what your doing.
How do you do it ? Im looking to plug my direct drive to my buffer tank but this has kept me from it, would you be happy to share
@@mrsparklewindowcleaning679first u have to install a 1" bulkhead fitting and a 1" pvc ball valve with a 1" threaded hose barb at the bottom of ur water supply tank..then all u have to do is raise up & mount your water supply tank atleast 2-4 inches above/higher than ur pressure washer pump water supply inlet is...! (U have to make sure that ur bulkhead fitting on the bottom of ur water tank is atleast 2-4 inches higher than ur pressure washers garden hose inlet)
Then hookup some 1" non-collapsible hose from ur water tank to ur pressure washer... hope this helps u.
No issues? I have a buffer tank and I’m going back and forth between a gear reduction box or just mounting the pump directly to the motor..
5.5gpm
You seem to be confusing "direct drive" with positive displacement pump (the pump type in your video), in your tutorial. The drive input does not determine what kind of pump it is, only what type of input it has.
The drive input has little to do with whether a pump will gravity draw its water, that's determined by your pump/tank set up. I've had experience with both Direct drive and centrifugal pumps for almost 30 years, using hundreds of pumps and have NEVER had a pump not draw from a tank because I understand how gravity works.
Correct- there's even hydraulic driven pumps that can take a generic hydro pto/remote power supply. Can't imagine I'd really want that in a normal situation, but I can come up with some usecases.