fuel pressure
 

What is the min and the max fuel pressure on the 24v

I wouldn't go below 5psi or above 18psi.

I have not gone below 37psi and up to 46psi for over 3 three years and close to 70K miles.

Dave

I know you have told me but what setup are you using?



Luke

geez, 37 at the lowest...that's wild...my air dog 150 keeps me at about 14-15 wot and 17-18 at idle...it seems pretty common that most people try to keep it above 10 but under 20...like mentioned though, id say 5psi would be the lowest...

Aren't most of the fuel pressure warning kits set for 5#'s cause anything below that will knock the injection pump out?

I was always told Low-5# & High-20# on a VP. :humm:

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

12V lift pump off a cam lobe.

Dave

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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

according to the factory cummins service manual in front of me, minimum pressure is 10, the dodge book says 7 psi, , id trust what cummins has in black and white vs dodge. hey dave, how did you get the 12 valve lift pump to work?

aftermarket cam. They come with the eccentric lobe to run the fuel pump. The hole in the block is covered by a plate on the 24v.