What's the fuel pressure output from a D-jet fuel pump? I'm looking at replacing my fuel pump with an in-line Holley or someother for space saving. I just don't want to have too high a pressure output that the regulator won't be able to compensate...
Thanks,
-Josh2
Full Version: Fuel Pump Pressure
'Bout 30 PSI.
That's the regulated pressure (28 psi) for the FI system... The output pressure from the pump has got to be a bit higher than that, otherwise the slightest dip in pump pressure would render the regulator useless. I'm looking for the pressure output directly from the pump.
-Josh2
-Josh2
QUOTE(jhadler @ Jun 8 2006, 05:45 PM) 
That's the regulated pressure (28 psi) for the FI system... The output pressure from the pump has got to be a bit higher than that, otherwise the slightest dip in pump pressure would render the regulator useless. I'm looking for the pressure output directly from the pump.
-Josh2
IIRC... if you deadhead the pump it will make somewhere close to 60 psi.
But I wouldn't do it for long.
Haynes manual....page 39
That's what I was looking for!! Thanks.
I'm looking at dropping in a holley in-line or something like that, but don't want to drive the regulator out of range.
Thanks!
-Josh2
That's the regulated pressure (28 psi) for the FI system... The output pressure from the pump has got to be a bit higher than that, otherwise the slightest dip in pump pressure would render the regulator useless. I'm looking for the pressure output directly from the pump.
-Josh2
IIRC... if you deadhead the pump it will make somewhere close to 60 psi.
But I wouldn't do it for long.
I'm looking at dropping in a holley in-line or something like that, but don't want to drive the regulator out of range.
Thanks!
-Josh2
QUOTE(ClayPerrine @ Jun 8 2006, 03:24 PM)
QUOTE(jhadler @ Jun 8 2006, 05:45 PM)
That's the regulated pressure (28 psi) for the FI system... The output pressure from the pump has got to be a bit higher than that, otherwise the slightest dip in pump pressure would render the regulator useless. I'm looking for the pressure output directly from the pump.
-Josh2
IIRC... if you deadhead the pump it will make somewhere close to 60 psi.
But I wouldn't do it for long.
Way to get in and get out. Good job not 
Mark D.
Mark D.
Strictly speaking, you're asking the wrong question. Pumps don't deliver "pressure", they deliver volume. The pressure is generated by restrictions downstream of the pump. More volume with the same restriction = more pressure. More volume with a lesser restriction = less pressure.
You're right in that you can generate too much volume to keep the pressure below the correct range for D-Jet, but the problem isn't so much the regulator as it is the size of the lines from the regulator back to the tank. With the regulator fully open, it's possible with sufficient volume to generate more than 30psi of line pressure, but that would require a LOT of volume.
Pump do have a pressure rating, which is what pressure they will pump AGAINST, which is why a carb pump can't be used to provide fuel for EFI, as those pumps will typically stall when line pressure downstream of them gets to be more than 5-10psi.
What you need to figure out when shopping for a pump is out much flow you're require for whatever power you're making. For 90hp, that's about 50 liters per hour. For 180hp, it's about 100 liters per hour. Etc. Find a pump that will deliver the required amount of volume and will do so at pressures up to at least 30-35psi, and you're fine.
You're right in that you can generate too much volume to keep the pressure below the correct range for D-Jet, but the problem isn't so much the regulator as it is the size of the lines from the regulator back to the tank. With the regulator fully open, it's possible with sufficient volume to generate more than 30psi of line pressure, but that would require a LOT of volume.
Pump do have a pressure rating, which is what pressure they will pump AGAINST, which is why a carb pump can't be used to provide fuel for EFI, as those pumps will typically stall when line pressure downstream of them gets to be more than 5-10psi.
What you need to figure out when shopping for a pump is out much flow you're require for whatever power you're making. For 90hp, that's about 50 liters per hour. For 180hp, it's about 100 liters per hour. Etc. Find a pump that will deliver the required amount of volume and will do so at pressures up to at least 30-35psi, and you're fine.
Thanks James,
Yeah, the pump I'm looking at right now is definitely sufficient. 67 Gph at 100 psi is the rating. More than sufficient for what I need. Waaaay more than sufficient.
My concern was if the pump would overwhelm the regulator and I wouldn't be able to dial the fuel pressure down to 30 psi for the D-Jet.
My plan is to run the D-Jet for a time, while I get the Megasquirt stuff together. But as long as I was putting in a different fuel pump, might as well be able to drive the MS setup as well...
-Josh2
Yeah, the pump I'm looking at right now is definitely sufficient. 67 Gph at 100 psi is the rating. More than sufficient for what I need. Waaaay more than sufficient.
My concern was if the pump would overwhelm the regulator and I wouldn't be able to dial the fuel pressure down to 30 psi for the D-Jet.
My plan is to run the D-Jet for a time, while I get the Megasquirt stuff together. But as long as I was putting in a different fuel pump, might as well be able to drive the MS setup as well...
-Josh2
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