pulsating pump?
- Thread starter rpk250
- Start date
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hehehe
Anyways, the shurflow has a pressure switch built in so that it will hit a certain pressure then shut the pump off, then come on again approximately 15-20psi below that switch point (think kinda like a fan switch). Problem easily fixed by running larger nozzle or placing a ball valve on the inlet side of the pump and turning it down till cycling goes awaya (in SEVERE situations, this wont work!). Also the valve inlet restriction trick will only work on a diaphram-style pump. Called up the engies at the plant fer that lil trick! You could also screw in the pressure switch setpoint by the setscrew in the switch head. Give her a turn or two, but dont go nuts, the pump head has a pressure limit. That will also help by raising the output pressure, allowing a lil more flow to the nozzle.
Also, get a smaller pump.... Ive seen all these DIYers driving these HUGE pumps into relatively small nozzles. I dont quite understand how people are trying to push 1.8GPM (thats gallons per minute pump output) into integer GPH nozzles.... Thats about ~ 30 times the overkill.....well probably "only" a 10X factor since you need some overshot in pump output rating due to losses. Compare a 340 with the 1.8GPM shurflow.... weird huh?
Put it this way.... we're using the 1.0GPM shurflow on the 1000+ HP BLow(me)zilla with NO flow limits through a few 5GPH nozzles.
You ideally want to eliminate the pulse as it WILL pulse the flow of the injection media (even if its barely noticeable) which probably dont matter for most apps - - i wouldnt worry too much. Accurate progressive injection is not possible if the pump cycles as the nozzle output will reach steady state. think bout it
peace out
heheheAnyways, the shurflow has a pressure switch built in so that it will hit a certain pressure then shut the pump off, then come on again approximately 15-20psi below that switch point (think kinda like a fan switch). Problem easily fixed by running larger nozzle or placing a ball valve on the inlet side of the pump and turning it down till cycling goes awaya (in SEVERE situations, this wont work!). Also the valve inlet restriction trick will only work on a diaphram-style pump. Called up the engies at the plant fer that lil trick! You could also screw in the pressure switch setpoint by the setscrew in the switch head. Give her a turn or two, but dont go nuts, the pump head has a pressure limit. That will also help by raising the output pressure, allowing a lil more flow to the nozzle.
Also, get a smaller pump.... Ive seen all these DIYers driving these HUGE pumps into relatively small nozzles. I dont quite understand how people are trying to push 1.8GPM (thats gallons per minute pump output) into integer GPH nozzles.... Thats about ~ 30 times the overkill.....well probably "only" a 10X factor since you need some overshot in pump output rating due to losses. Compare a 340 with the 1.8GPM shurflow.... weird huh?
Put it this way.... we're using the 1.0GPM shurflow on the 1000+ HP BLow(me)zilla with NO flow limits through a few 5GPH nozzles.
You ideally want to eliminate the pulse as it WILL pulse the flow of the injection media (even if its barely noticeable) which probably dont matter for most apps - - i wouldnt worry too much. Accurate progressive injection is not possible if the pump cycles as the nozzle output will reach steady state. think bout it
peace out
Yes and no.
See if you start the pump at lower voltages it will develop pressure in a linear fashion as the voltage to it increases. More voltage=more the pump spins.
Now if you set the pressure on the head to lets say 60 psi and use a small nozzle, then it will hit the 60 psi probably after a few volts. If the pump is a 150 PSI pump and it takes lets say 9 volts to develop this 150 PSI, then having a system that progressively ramps voltage up to 9 makes a nice pressure swing. If the motor needs 150 PSI, and if the controller goes up to 9. "IF"... If all thats needed is let say 120 PSI, then applying less voltage yields like 7.5 will yield that pressure and not have issues of it cycling.
Its all bout playing with pressure, volume, and voltage. Get the correct combo of all three.. it makes a wicked setup.
So you can run 4 nozzles at 60 PSI or one at 150 PSI.. just depends how much volume you want at what level boost. I tend to favor higher pressure for head pressure.. ie, the inside of the pipe is at 30 PSI.. pump is at 150.. thats 120 effective. 120 is a lot. vs.. inside the pipe its 30 PSI, pump is at 60.. thats 30 difference. 120 vs 30 .. hummm.
Back under my rock
See if you start the pump at lower voltages it will develop pressure in a linear fashion as the voltage to it increases. More voltage=more the pump spins.
Now if you set the pressure on the head to lets say 60 psi and use a small nozzle, then it will hit the 60 psi probably after a few volts. If the pump is a 150 PSI pump and it takes lets say 9 volts to develop this 150 PSI, then having a system that progressively ramps voltage up to 9 makes a nice pressure swing. If the motor needs 150 PSI, and if the controller goes up to 9. "IF"... If all thats needed is let say 120 PSI, then applying less voltage yields like 7.5 will yield that pressure and not have issues of it cycling.
Its all bout playing with pressure, volume, and voltage. Get the correct combo of all three.. it makes a wicked setup.
So you can run 4 nozzles at 60 PSI or one at 150 PSI.. just depends how much volume you want at what level boost. I tend to favor higher pressure for head pressure.. ie, the inside of the pipe is at 30 PSI.. pump is at 150.. thats 120 effective. 120 is a lot. vs.. inside the pipe its 30 PSI, pump is at 60.. thats 30 difference. 120 vs 30 .. hummm.
Back under my rock
.... rpk250 r u running a progressive controller?
I didnt get the impression that he was running progressive.
But if you are:
If your pump cycles anywhere in the range that you wish to inject in, then its too big for the nozzle because then you loose range because now you have to stop the pump short. ANything more yields a saturated boost to alky volume curve (hmm sounds like we're talkin bout iv curves or sumin) and you might as well pop a hobbs switch back in. And since you can't lower initial pump speed (ie pump voltage) below what the motor torques require to spin the motor due to inertial laws & PWM waveform power/cycle (dir. rel. to PWM frequency), you can only change nozzle sizes... if you increase the initial turnon pump speed to compensate, you also hurt the KR mapping to the alky injection curve. Since knock retard starts out from 0 and works relatively linearly upwards, your turning the pump on higher will only add more and more 'step' to the curve when the injection turns first on (ie you loose power due to too much being injected). After all, you cant start the pump right from 0V, you can only get close to it.
Oh and razor... I know your kits work great and you use the big mammajamma shurflo, so my lecturing doesnt apply to ya
You've got that thing spinning slow enough I'd imagine.
good day folks
I didnt get the impression that he was running progressive.
But if you are:
If your pump cycles anywhere in the range that you wish to inject in, then its too big for the nozzle because then you loose range because now you have to stop the pump short. ANything more yields a saturated boost to alky volume curve (hmm sounds like we're talkin bout iv curves or sumin) and you might as well pop a hobbs switch back in. And since you can't lower initial pump speed (ie pump voltage) below what the motor torques require to spin the motor due to inertial laws & PWM waveform power/cycle (dir. rel. to PWM frequency), you can only change nozzle sizes... if you increase the initial turnon pump speed to compensate, you also hurt the KR mapping to the alky injection curve. Since knock retard starts out from 0 and works relatively linearly upwards, your turning the pump on higher will only add more and more 'step' to the curve when the injection turns first on (ie you loose power due to too much being injected). After all, you cant start the pump right from 0V, you can only get close to it.
Oh and razor... I know your kits work great and you use the big mammajamma shurflo, so my lecturing doesnt apply to ya
You've got that thing spinning slow enough I'd imagine.good day folks
