After Market Fuel Pumps
07-17-2005 | 02:26 AM
#16
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From: Post Falls, Idaho
Originally posted by Superduty
"My EZ set on #2 and up will suck my lift pump fuel pressure to "0" very easily. Now with the Juice with Attitufe it is even quicker to "0" pressure!"
I wouldn't run it like that. The CP3 relies on excess fuel flow for cooling, just like the VP44 did, although not to the same extent.
"My EZ set on #2 and up will suck my lift pump fuel pressure to "0" very easily. Now with the Juice with Attitufe it is even quicker to "0" pressure!"
I wouldn't run it like that. The CP3 relies on excess fuel flow for cooling, just like the VP44 did, although not to the same extent.
07-17-2005 | 08:45 AM
#17
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From: Swisher, IA
If you want to build your own fuel system, I would go with the Holley blue pump. That is what I did. It has been installed for about 5K miles now. I have had no problems.
The Holley supplies more volume than stock with only 14PSI of pressure. When fueling with a performance box, it will only drop to about 9PSI under load instead of 0. The factory pump is supposed to supply 11PSI no load. I would hesitate installing any pump that is supplying 60PSI of pressure to the CP3 without a regulator. High pressure pumps (excluding the CP3) are great for gassers, but you want to find a lower pressure high volume pump so the CP3 doesn't starve.
I have pics in my gallery of my install.
-Muzzy
The Holley supplies more volume than stock with only 14PSI of pressure. When fueling with a performance box, it will only drop to about 9PSI under load instead of 0. The factory pump is supposed to supply 11PSI no load. I would hesitate installing any pump that is supplying 60PSI of pressure to the CP3 without a regulator. High pressure pumps (excluding the CP3) are great for gassers, but you want to find a lower pressure high volume pump so the CP3 doesn't starve.
I have pics in my gallery of my install.
-Muzzy
07-17-2005 | 12:36 PM
#18
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"Wonder how the DuraMax who also has a Bosch CP3 continues to perform with a lift pump at all?"
Interesting you bring that up... I was going to comment on the Duramax not having a lift pump and then I checked the manual and the wiring diagrams do show a lift pump. I don't know if they have one or not. I suspect they do have an in tank lift pump. I suspect that people thought they didn't because there is no engine mounted lift pump and the lift pump is hidden in the tank.
"If you want to build your own fuel system, I would go with the Holley blue pump. That is what I did. It has been installed for about 5K miles now. I have had no problems. "
What makes the holley blue pump any better than any other pump ?
"The Holley supplies more volume than stock with only 14PSI of pressure. When fueling with a performance box, it will only drop to about 9PSI under load instead of 0. The factory pump is supposed to supply 11PSI no load. I would hesitate installing any pump that is supplying 60PSI of pressure to the CP3 without a regulator. High pressure pumps (excluding the CP3) are great for gassers, but you want to find a lower pressure high volume pump so the CP3 doesn't starve."
Huh ? All pumps do is pump fuel. They don't set pressure. Something else in the flow path provides restriction and thus sets the pressure for the system. Your holley pump doesn't set the pressure to be 14PSI. Your Holly just tries to pump X volume of fuel per minute or hour. The restriction in the CP3 to this flow rate sets the backpressure.
There is no such thing as a high flow/low pressure pump. Assuming the CP3 restriction is the same for all pumps (ie we aren't changing the CP3), the higher the pump flow the higher the pressure is going to be. Period. Regardless of brand. End of story.
BTW: Is your Holley specified to pump diesel fuel ? Some pumps aren't.
Interesting you bring that up... I was going to comment on the Duramax not having a lift pump and then I checked the manual and the wiring diagrams do show a lift pump. I don't know if they have one or not. I suspect they do have an in tank lift pump. I suspect that people thought they didn't because there is no engine mounted lift pump and the lift pump is hidden in the tank.
"If you want to build your own fuel system, I would go with the Holley blue pump. That is what I did. It has been installed for about 5K miles now. I have had no problems. "
What makes the holley blue pump any better than any other pump ?
"The Holley supplies more volume than stock with only 14PSI of pressure. When fueling with a performance box, it will only drop to about 9PSI under load instead of 0. The factory pump is supposed to supply 11PSI no load. I would hesitate installing any pump that is supplying 60PSI of pressure to the CP3 without a regulator. High pressure pumps (excluding the CP3) are great for gassers, but you want to find a lower pressure high volume pump so the CP3 doesn't starve."
Huh ? All pumps do is pump fuel. They don't set pressure. Something else in the flow path provides restriction and thus sets the pressure for the system. Your holley pump doesn't set the pressure to be 14PSI. Your Holly just tries to pump X volume of fuel per minute or hour. The restriction in the CP3 to this flow rate sets the backpressure.
There is no such thing as a high flow/low pressure pump. Assuming the CP3 restriction is the same for all pumps (ie we aren't changing the CP3), the higher the pump flow the higher the pressure is going to be. Period. Regardless of brand. End of story.
BTW: Is your Holley specified to pump diesel fuel ? Some pumps aren't.
07-17-2005 | 03:46 PM
#19
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From: Swisher, IA
Superduty-
First of all, I wasn't implying that your Walbro pump would not work fine, I would just make sure to have a regulator to run the pressure down a bit.
The Holley blue pump has been used by many in this forum with success. It is relatively inexpensive ($100), rebuildable, and can be found through many retailers if a replacement was needed. At the preset pressure of 14PSI, you can install it without a regulator.
As far as pressure or volume pumps... If I remember correctly from my fluid dynamics class in college, there is a difference between pumps that make lots of pressure and those that supply large volume( I realize that the pressure is produced by restriction to flow). It is possible through the design of the pump to have a low pressure high volume pump (centrifugal pumps vs. positive displacement gearator style pumps) . For example the Holley Volumax will flow 250GPH no load. It is set to only 15 PSI and will not make much more since it is designed for a carbureted engine. On the converse side, I bought a 255LPH pump for my wife's car that is rated up to 90 PSI, meaning it is capable of producing pressures up to 90PSI unregulated. With the return line fuel system I built, I tuned the regulator to 32PSI at idle and 82PSI at full boost. A Holley or any other pump designed for carburetor applications would not be able to hit those pressures. My point was to select a fuel pump that is engineered more for carbureted use than fuel injection.
Holley did say it was compatible with diesel fuel when I spoke with them.
-Muzzy
First of all, I wasn't implying that your Walbro pump would not work fine, I would just make sure to have a regulator to run the pressure down a bit.
The Holley blue pump has been used by many in this forum with success. It is relatively inexpensive ($100), rebuildable, and can be found through many retailers if a replacement was needed. At the preset pressure of 14PSI, you can install it without a regulator.
As far as pressure or volume pumps... If I remember correctly from my fluid dynamics class in college, there is a difference between pumps that make lots of pressure and those that supply large volume( I realize that the pressure is produced by restriction to flow). It is possible through the design of the pump to have a low pressure high volume pump (centrifugal pumps vs. positive displacement gearator style pumps) . For example the Holley Volumax will flow 250GPH no load. It is set to only 15 PSI and will not make much more since it is designed for a carbureted engine. On the converse side, I bought a 255LPH pump for my wife's car that is rated up to 90 PSI, meaning it is capable of producing pressures up to 90PSI unregulated. With the return line fuel system I built, I tuned the regulator to 32PSI at idle and 82PSI at full boost. A Holley or any other pump designed for carburetor applications would not be able to hit those pressures. My point was to select a fuel pump that is engineered more for carbureted use than fuel injection.
Holley did say it was compatible with diesel fuel when I spoke with them.
-Muzzy
07-17-2005 | 07:38 PM
#20
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From: I'll look into that!
Well, I asked this question once before and got no good info so here it is again:
What would be better for a high HP motor a fuel pump that supplies 14psi @ 140GPh or 15 psi @ 100 GPH?
What would be better for a high HP motor a fuel pump that supplies 14psi @ 140GPh or 15 psi @ 100 GPH?
07-17-2005 | 08:00 PM
#21
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From: michigan
Originally posted by Mark Thomas
Well, I asked this question once before and got no good info so here it is again:
What would be better for a high HP motor a fuel pump that supplies 14psi @ 140GPh or 15 psi @ 100 GPH?
Well, I asked this question once before and got no good info so here it is again:
What would be better for a high HP motor a fuel pump that supplies 14psi @ 140GPh or 15 psi @ 100 GPH?
07-18-2005 | 07:55 AM
#22
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From: Swisher, IA
Mark Thomas-
I would say the pump that produces 140GPH at 14 PSI would be a better choice. The 1PSI increase in pressure would be offset by the extra 40GPH of volume the other pump offers. You just want to make sure the CP3 isn't starving. Plus, the CP3 doesn't really require that much pressure.
-Muzzy
I would say the pump that produces 140GPH at 14 PSI would be a better choice. The 1PSI increase in pressure would be offset by the extra 40GPH of volume the other pump offers. You just want to make sure the CP3 isn't starving. Plus, the CP3 doesn't really require that much pressure.
-Muzzy
07-18-2005 | 09:03 AM
#23
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From: Moved.......now Sumter, SC
A couple things to add that may help.
On pressure……When the FASS first came out I was a little worried about the CP3 having that much pressure behind it at all times as things were still new back then and we (forum users) were not sure how the CP3 would react to it over long term use. The folks at DPP had told me that during testing, the CP3 never gave them any trouble until pressures got above 48psi for a couple thousand miles. They didn’t elaborate on what problems arose after 48psi and I didn’t ask. I was just happy that they had tried it and found the breaking point (for lack of a better term) and would stay well under that point. So, I suppose you may want to use a regulator if you run a pump that provides 50+psi of pressure. Those CP3s are mighty expensive.
On volume……..I originally purchased a 150gph FASS and had a lot of cavitation problems with it. Spent a lot of time on the phone with DPP trying different things to isolate the problem, and low and behold, the 95gph FASS was born. The end result was the stock fuel pick-up tube inside the fuel tank is too small to support the amount of volume that 150gph requires. The amount of vacuum in the lines that the FASS created because not enough fuel was available caused it to suck in air from every not-so-perfectly-sealed joint between it and the tank. Once swapped out with a then new 95gph unit, the cavitation went away. Over time my trained ear got to where I thought I could still hear just the faintest hint of cavitation (or what I thought was cavitation) and I ended up replacing the 1/4" fuel pick-up tube inside the tank with a 1/2" pick-up tube. It has been running smooth as silk ever since. Given that, I would suggest that something that provides just a tad under 95gph would probably be ideal, say 80 to 85gph.
On "what is enough"…..Currently running the 95gph FASS and with my 1/4 mile times, rwhp for this 7,900lb truck should be in the 580+ range. On a 1/4 mile run, pressure at the CP3 does not drop below 13lbs. This is with a 15lb regulator spring, 3-Micron filter on the FASS, and sucking through a Racor Nomad fuel heater. This would indicate that 95gph is more than plenty for most everyone's needs and may even be overkill. Just to give you an indication of what kind of volume your pump of choice would need. I could probably be running a pump that provides 50gph (and to think how much quieter that would be) and still couldn't drop pressure to zero at WOT.
Hope that helps.
On pressure……When the FASS first came out I was a little worried about the CP3 having that much pressure behind it at all times as things were still new back then and we (forum users) were not sure how the CP3 would react to it over long term use. The folks at DPP had told me that during testing, the CP3 never gave them any trouble until pressures got above 48psi for a couple thousand miles. They didn’t elaborate on what problems arose after 48psi and I didn’t ask. I was just happy that they had tried it and found the breaking point (for lack of a better term) and would stay well under that point. So, I suppose you may want to use a regulator if you run a pump that provides 50+psi of pressure. Those CP3s are mighty expensive.
On volume……..I originally purchased a 150gph FASS and had a lot of cavitation problems with it. Spent a lot of time on the phone with DPP trying different things to isolate the problem, and low and behold, the 95gph FASS was born. The end result was the stock fuel pick-up tube inside the fuel tank is too small to support the amount of volume that 150gph requires. The amount of vacuum in the lines that the FASS created because not enough fuel was available caused it to suck in air from every not-so-perfectly-sealed joint between it and the tank. Once swapped out with a then new 95gph unit, the cavitation went away. Over time my trained ear got to where I thought I could still hear just the faintest hint of cavitation (or what I thought was cavitation) and I ended up replacing the 1/4" fuel pick-up tube inside the tank with a 1/2" pick-up tube. It has been running smooth as silk ever since. Given that, I would suggest that something that provides just a tad under 95gph would probably be ideal, say 80 to 85gph.
On "what is enough"…..Currently running the 95gph FASS and with my 1/4 mile times, rwhp for this 7,900lb truck should be in the 580+ range. On a 1/4 mile run, pressure at the CP3 does not drop below 13lbs. This is with a 15lb regulator spring, 3-Micron filter on the FASS, and sucking through a Racor Nomad fuel heater. This would indicate that 95gph is more than plenty for most everyone's needs and may even be overkill. Just to give you an indication of what kind of volume your pump of choice would need. I could probably be running a pump that provides 50gph (and to think how much quieter that would be) and still couldn't drop pressure to zero at WOT.
Hope that helps.
07-18-2005 | 09:14 PM
#25
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Joined: Oct 2003
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From: Moved.......now Sumter, SC
I grabbed a pick-up tube assembly from my local Kenworth service center for $24. It is the same standard pick-up tube assembly they use in big rig tanks. Dropped my tank, found a suitable place to put it, drilled hole, installed bulkhead fitting and pick-up tube, re-installed tank, hooked up FASS feed line. Whole process took about two hours. Not hard at all. The stock pick-up tube is still there and hooked up to the stock fuel lines all the way to the engine compartment. If I need to hook the stock lift pump back up for some reason (FASS dies), I can do so in about 15 minutes with a pair of pliers. If I had to do it again I would do a bottom feed instead of a top feed.
07-19-2005 | 07:13 AM
#27
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Since we are using a FASS with the filtering capability does there really need to be a screen or can we just put a bigger tube straight into the tank? There used to be vendors that sold kits for doing this same thing on the PSDs. I would be very suprised if there isnt someone selling them for the Dodges.
07-19-2005 | 09:38 AM
#28
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From: Moved.......now Sumter, SC
Sorry...I don't have any part numbers. Most truck service centers will have several pick-up tube assemblies to choose from. Just have to pick the one that looks the best to you.
The one I got was made to screw into an existing fitting on big metal tanks. After picking it up, I stopped by a hardware store with it and got a bulkhead fitting to fit it as well as a push lock fitting for the other end for the FASS fuel line to slip over. These two pieces cost me another $6 maybe and are common, easy to find parts.
I would consider a bottom feed though versus a top feed pick-up tube. The truck service centers have these as well. Problem is with mine, if I run the tank down to almost empty, when I hit the brakes hard and all the fuel flows to the front of the tank, fuel pressure drops to about 3 lbs for a split second (new tube is towards the back of the tank). This won't happen with a bottom feed…..or make a point to put the new tube towards the front of the tank.
GDH11 brought up a good point. Have you ever had the stock pick-up tube assembly out of the tank? The line is small and has a very fine screen over the end to further restrict things. If you have a FASS that is sucking air, you could probably do wonders just by removing the screen. Probably not needed and is serving no real function unless kids are constantly putting tree bark down your fill tube.
The one I got was made to screw into an existing fitting on big metal tanks. After picking it up, I stopped by a hardware store with it and got a bulkhead fitting to fit it as well as a push lock fitting for the other end for the FASS fuel line to slip over. These two pieces cost me another $6 maybe and are common, easy to find parts.
I would consider a bottom feed though versus a top feed pick-up tube. The truck service centers have these as well. Problem is with mine, if I run the tank down to almost empty, when I hit the brakes hard and all the fuel flows to the front of the tank, fuel pressure drops to about 3 lbs for a split second (new tube is towards the back of the tank). This won't happen with a bottom feed…..or make a point to put the new tube towards the front of the tank.
GDH11 brought up a good point. Have you ever had the stock pick-up tube assembly out of the tank? The line is small and has a very fine screen over the end to further restrict things. If you have a FASS that is sucking air, you could probably do wonders just by removing the screen. Probably not needed and is serving no real function unless kids are constantly putting tree bark down your fill tube.
07-19-2005 | 11:17 AM
#29
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From: In front of the black cloud, MO
Superduty---- I don't think your Walbro idea will work, although I haven't tried it on a CP3 equipped truck, I did try it on an 02 VP44 truck. I figured that, being a return-style fuel system, the pressure wouldn't build too high.... I was wrong, the truck ran for about 30seconds then it blew the top out of the filter assembly!
I think if you install a bigger return line it might be okay, but why bother. There are easier options out there. The holley blue does work nice, and the cleanest install is the Carter kit from Diesel dynamics or the FASS/AirDog.
I think if you install a bigger return line it might be okay, but why bother. There are easier options out there. The holley blue does work nice, and the cleanest install is the Carter kit from Diesel dynamics or the FASS/AirDog.
07-19-2005 | 07:49 PM
#30
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I don't know if it will work or not, but why do you say the return line is too small ?
Remember that I am doing this in a FORD Superduty with a 325/600 Cummins installed in it. The same pump ran with the Ford setup just fine, ie the return line wasn't too small. Why would it be too small now ?
The thing that will make or break this application of the Walbro is the restriction of the CP3. Others in this post are claiming 50PSI into a CP3. I assume that is with a stock filter housing. I'll check the pressure once I get it running.
Remember that I am doing this in a FORD Superduty with a 325/600 Cummins installed in it. The same pump ran with the Ford setup just fine, ie the return line wasn't too small. Why would it be too small now ?
The thing that will make or break this application of the Walbro is the restriction of the CP3. Others in this post are claiming 50PSI into a CP3. I assume that is with a stock filter housing. I'll check the pressure once I get it running.