fuel pressure
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yeah, getting it down to 5psi wont kill it but it isnt good for it either...ive hit zero before my lift pump (hopefully i got it on in time...no problems with it yet)...if you get a quality unit like an air dog or fass system, you pretty much wont have to worry about fp again...unless of course you're going for mega power
#8
12V lift pump off a cam lobe.
Dave
---AutoMerged DoublePost---
Most of the information is incorrect IMO on the internet forums regarding fuel pressure in the VP44.
However, through some testing, we have determined you should never run pressure below 8-10psi under ANY circumstances depending on the actual ID of the fuel inlet fitting. Since I run a 14mm inlet, my actual "required" pressure is lower still.
With that said, this does not mean this the "correct" info. This is based on the minimum fueling needed to run 500HP and still provide for some excess returned fuel. In my estimation, returned fuel is the keystone to proving that there is probably enough fuel in the pump.
The high pressures I run were at first just because I did not have a regulator. After a while, I had no ill effects and it became a test bed to see how long the VP would last. Since the time I did my install, I have installed cams, 12 valve lift pumps and similar setups to a few other trucks. Combined, there is over 600K miles and counting with no VP failures.
We are still waiting for the diaphragm to rupture. Or the pump to stop. It'll happen someday, but we'll not know the "damage" until they get torn down and completely rebuilt. We actually hope to see some effects from high fuel pressure. This will help us dial it down to the point that no additional wear occurs and yet give us the ultimate answer of how much is too much.
One thing to keep in mind with regards to high pressure, this 20# recommendation is due to the electric fuel pump. Since hard starts can occur if the pressure is too high before the truck cranks over. I don't have any pressure until the truck cranks. By the time it fires, I have full pressure. So, my conditions are a little different.
The purpose of all this? Just to say that there is not always one way to accomplish your goals.
Dave
Dave
---AutoMerged DoublePost---
Most of the information is incorrect IMO on the internet forums regarding fuel pressure in the VP44.
However, through some testing, we have determined you should never run pressure below 8-10psi under ANY circumstances depending on the actual ID of the fuel inlet fitting. Since I run a 14mm inlet, my actual "required" pressure is lower still.
With that said, this does not mean this the "correct" info. This is based on the minimum fueling needed to run 500HP and still provide for some excess returned fuel. In my estimation, returned fuel is the keystone to proving that there is probably enough fuel in the pump.
The high pressures I run were at first just because I did not have a regulator. After a while, I had no ill effects and it became a test bed to see how long the VP would last. Since the time I did my install, I have installed cams, 12 valve lift pumps and similar setups to a few other trucks. Combined, there is over 600K miles and counting with no VP failures.
We are still waiting for the diaphragm to rupture. Or the pump to stop. It'll happen someday, but we'll not know the "damage" until they get torn down and completely rebuilt. We actually hope to see some effects from high fuel pressure. This will help us dial it down to the point that no additional wear occurs and yet give us the ultimate answer of how much is too much.
One thing to keep in mind with regards to high pressure, this 20# recommendation is due to the electric fuel pump. Since hard starts can occur if the pressure is too high before the truck cranks over. I don't have any pressure until the truck cranks. By the time it fires, I have full pressure. So, my conditions are a little different.
The purpose of all this? Just to say that there is not always one way to accomplish your goals.
Dave
Last edited by Fishin2Deep4U; 02-08-2009 at 10:58 PM. Reason: Automerged Doublepost
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