Made in USA 12V diesel pumps

NPT90

NPT90

Well-known member
Facet Duralift

I am considering going this route, you can dial them down to pretty low pressure and it has a built it sedimenter to catch the crap.

I don't want to overfuel my IP or stress out the lift pump so setting this to 4PSI and letting the fuel system do the rest is pretty ideal.

From what I have seen on the internet these will feed a 7.3L ford diesel truck so it should easily keep up with my 300TDI demands
 
C

copleymotorcars

Well-known member
the dodge guys with the VE pumps are running 10-15psi in aftermarket electric lift pump applications without issue. what they like to do, is run a fuel pressure gauge between lift pump and IP and monitor to ensure that the pressure never reaches zero at full load. ensuring the IP is always being fed rather than having to draw.

important to note, any extra fuel being pumped to the IP flows through the pump body and back to the tank by the return port, thereby cooling the pump. not a bad thing for longevity.

adam
 
NPT90

NPT90

Well-known member
copleymotorcars said:
the dodge guys with the VE pumps are running 10-15psi in aftermarket electric lift pump applications without issue. what they like to do, is run a fuel pressure gauge between lift pump and IP and monitor to ensure that the pressure never reaches zero at full load. ensuring the IP is always being fed rather than having to draw.

important to note, any extra fuel being pumped to the IP flows through the pump body and back to the tank by the return port, thereby cooling the pump. not a bad thing for longevity.

adam
Click to expand...

That's right, there is a fuel return banjo on the back of the pump.

Interesting essentially you can't over pressure them then...
 
R

Red90

Well-known member
Just use the 4-6 psi pump. It will be safe. Running higher pressures causes changes to the timing advance and you are more likely to blow out the shaft seal.

VE pumps are actually designed to not use a lift pump and suck from the tank, but the low pressure pumps are acceptable.
 
R

Red90

Well-known member
copleymotorcars said:
important to note, any extra fuel being pumped to the IP flows through the pump body and back to the tank by the return port, thereby cooling the pump. not a bad thing for longevity.

adam
Click to expand...

The lift pump pressure really has little effect on the flow that returns to the tank. The tank return is controlled by the overflow restrictor that is built into the banjo bolt of the return line connector. This sees pump body pressure, which is much higher than fuel supply pressure. The amount of fuel returned is more or less varied with engine speed as pump body pressure increases with speed.

The problem with too high of a feed pressure is two fold. First it causes the feed pump to develop a higher body pressure than designed. This result in the timing advance opening earlier than intended. The second is that the supply pressure acts directly on the shaft seal, so any extra pressure leads to a high probability of a leak.

If you read the VE manuals, you will see that Bosch intended that there not be a lift pump. So, keep the pressure low.
 
NPT90

NPT90

Well-known member
silly question maybe, if I route a separate pickup from the tank directly to the filter and bypass the lift pump on the engine (leaving that system intact) would I run the risk of back pressure to the lift pump or would all of the pressure go forward to the IP?
 
AdamSanta85

AdamSanta85

Well-known member
NPT90 said:
silly question maybe, if I route a separate pickup from the tank directly to the filter and bypass the lift pump on the engine (leaving that system intact) would I run the risk of back pressure to the lift pump or would all of the pressure go forward to the IP?
Click to expand...

You are way overthinking/overengineering this thing. A regular low pressure pump spliced inline works perfect.
 
R

Red90

Well-known member
jymmiejamz said:
So the is IP designed to function as a suction pump like the early Puma trucks use?
Click to expand...

Yes. The VE pump has a rotary vane pump where the fuel enters. It increases the pressure of the fuel inside the entire body of the pump. Excess fuel bleeds back to the tank through a restrictor in the outlet connection banjo bolt. This pressure is also used to control the timing advance mechanism.

The manual states that applications with a high lift will need a lift pump, but there is no specification on the pressure. They are simply wanting to prevent cavitation. In both the Land Rover and Dodge truck application, lift pumps were used. Dodge says 3 to 5 psi and Land Rover says 3 to 4 psi.

Here is the text from the Bosch manual:
Fuel-line configuration
For the injection pump to function efficiently it is necessary that its high pressure stage is continually provided with pressurized fuel which is free of vapor bubbles. Normally, in the case of passenger cars and light commercial vehicles, the difference in height between the fuel tank and the fuel-injection equipment is negligible. Furthermore, the fuel lines are not too long and they have adequate internal diameters. As a result, the vane-type supply pump in the injection pump is powerful enough to draw the fuel out of the fuel tank and to build up sufficient pressure in the interior of the injection pump. In those cases in which the difference in height between fuel tank and injection pump is excessive and (or) the fuel line between tank and pump is too long, a pre-supply pump must be installed. This overcomes the resistances in the fuel line and the fuel filter. Gravity-feed tanks are mainly used on stationary engines.
Click to expand...
 
javelinadave

javelinadave

Administrator
Staff member
I have a Robert Davis sedimenter that I need to install when I install the fuel pump. #selfbleedingfuelsystemisthenewairlocker
 
You must log in or register to reply here.
Top