Lift Pump Pressure

[SS396]

Installed my FM100 series filter/lift pump combo to complement my Mega filter over the weekend. What PSI are most of you running?

Scott at Reliable Industries claims these pumps are pretty reliable (no pun intended) and should last a long time, I put a bypass in just in case and to control the pressure

Presently i have mine set at 1.5 PSI at idle, it will drop to around 0 PSI at 2500 RPM (no load). I am using the Parker N-600-S needle valve in the by-pass, I am surprised how sensitive this valve is, just a quarter of a turn can increase PSI by 1, well worth the money. The valve has color bands for rough adjustment, then the knob has 10 increments for finer adjustments. The nice thing it has a set screw to lock in place.

[jbplock]

Pat,

Where/how are you measuring the pressure? I have mine set for 0.4 psi at the schrader valve (at idle). I haven't checked mine, but I would guess that this would correspond to 3-4 psi at the lift pump outlet. The Parker valve sounds nice too. Mine isn't as precise as you are describing.

[SS396]

I am probably measuring at the wrong spot, but I check at the dirty side bleed port on the Mega.

Eventually I will want to check at the schrader valve, but I will need to purchase a coupler and decent gauge.

[Kennedy]

I've been running 5-6 psi at idle measured at the Schrader port.

[jbplock]

Originally posted by SS396:
... I check at the dirty side bleed port on the Mega ... Measuring at the bleeder works... I also have a low cost gauge on the bleeder fitting. If I set the schrader valve pressure at 0.4psi as read by the Kent Moore Gauge, the bleeder gauge reads slightly above the zero psi mark. The resolution of the bleeder gauge isn't too good around zero but it does provide a good way to monitor changes.


Originally posted by kennedy:
I've been running 5-6 psi at idle measured at the Schrader port. John,
Just curious

[Kennedy]

That is what the pump delivers on it's own.

I had the EP 158 on first and it ran 10- 12 psi with engine standing still, and 8 or so at idle. I now have the 309 and it runs 6-8 with about 4-6 at idle.

[GM Smitty]

I've been running mine at 2psi measured at the Mega out port. Using the same needle valve as SS396. He's right, it doesn't take much of a turn to really affect pressure.

Josh smile.gif

[ratlover]

So you just have it dead headed off the pumps bypass(does the pump have a built in by pass on the outlet?) No issues with that much PSI obviously

Thanks

[sdaver]

5 psi post 2 micron added filter preoem

[jbplock]

Originally posted by ratlover:
... does the pump have a built in by pass on the outlet? ... The Stanadyne FM100 or the AC Delco EP158 (EP309 ??) do not have a built in regulator.

[ 09-17-2003, 04:56 PM: Message edited by: jbplock ]

[jbplock]

According to a post by tom mac 95 in the 2 Lift Pumps topic (http://forum.thedieselpage.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=1;t=004629)(6.5L Turbo Diesel forum) (http://forum.thedieselpage.com/cgi-bin/ultimatebb.cgi?ubb=forum;f=1), the AC Delco EP309 lift pump DOES have an internal regulator. This would explain why it runs at a lower pressure than the EP158 (also the higher price). It's also interesting that some of the 6.5 guys are running TWO lift pumps :eek:

[Lone Eagle]

I don't know if I have any business commenting on this topic since I don't have an extra lift pump but I do know a little about valves. A needle valve is not a pressure regulator. It is used to meter flow. No manually set valve will maintain a set pressure/flow when the system flow rate is constantly changing. A pressure regulator is the correct valve but it doesn't sound like one is needed if the pumps have a built in relief valve. (bypass)
Any pressure above the vapor point should work. It sounds like the OEM transfer pump works fine with all the different pressures you guys are running. Later! Frank

[jbplock]

Frank,

You bring up an interesting point .... The needle valve I have in my set up is in a bypass loop around the lift-pump/pre-filter (http://community.webshots.com/photo/77018086/77108574VFZuzV). I was under the impression that once the valve was set for a given pressure at the output of the tee, pressure would be held constant at the output of the tee for some limited range of flow rates. Is this not the case? I appreciate your insight on this subject

[Lone Eagle]

Bill, Your needle valve is plumbed it more like a relief valve. The purpose of which is to protect the system from over pressure. Pressure regulators and flow control valves are in series with the pump. (like a pressure regulator on your air compressor) It sounds like your system is working so I don't see a problem. Later! Frank