E pump b.s.

[Garbage_Mechan]

One thing you can't do with a mechanical pump...

Bring the system up to pressure without cranking the engine over. (And over and over and ov.......)

THIS is the key reason for me. I have run into battery / starter issues before trying to recover from a minor fuel supply problem. The last time I was a ways from help when it stalled while off road. Grabbed air somehow and since it was essentially idling at the time (up a steep rough incline) it got pretty loaded with air. Even after cracking a few high pressure lines loose it just did start before the batteries died.
( Always keep a 5/8 wrench in the truck)

 

[Cubey]

THIS is the key reason for me. I have run into battery / starter issues before trying to recover from a minor fuel supply problem. The last time I was a ways from help when it stalled while off road. Grabbed air somehow and since it was essentially idling at the time (up a steep rough incline) it got pretty loaded with air. Even after cracking a few high pressure lines loose it just did start before the batteries died.
( Always keep a 5/8 wrench in the truck)

I carry an old Yamaha 500W generator with a built in 12v battery charger. So yeah, a gas powered battery charger. But I also have a smart battery charger that can be run from the generator so... it's kind of redundant. The generator's is a dumb charger.

 

[dgr]

I'll give you that, because I don't know any better.

But we aren't running cummins. I was talking about our mechanical pump.

Haha

We're talking about their mechanical lift pump. 94-98 12V

I did find an article that states the efficiency is crap. Which I find interesting and germane to our fuel delivery.

http://www.torkteknology.com/technical-article-1-cummins-lift-pump/

Looks like they max output is 36 gph. HP is fuel limited. Stock 12V produces 235 HP. Why do we need so much volume to keep pressure to the IP above 0 PSI?

 

[Thewespaul]

Haha

We're talking about their mechanical lift pump. 94-98 12V

I did find an article that states the efficiency is crap. Which I find interesting and germane to our fuel delivery.

http://www.torkteknology.com/technical-article-1-cummins-lift-pump/

Looks like they max output is 36 gph. HP is fuel limited. Stock 12V produces 235 HP. Why do we need so much volume to keep pressure to the IP above 0 PSI?

Inline pump is set timing, our pumps have a hydraulic advance circuit that takes fuel volume that the inline pump doesn’t have. On my 20hp test stand (2600lbs antique) the supply pump maxed out can supply 100 psi solid to a pretty hot p7100. On my 400cc db2, it was dropping from 100 psi to 40psi at high rpms, and it’s rated at 200gph.

 

[dgr]

Good stuff Wes. My understanding of what you posted is the advance is bypassing a ton of fuel to operate. Fuel supplied - advance bypass = hp potential. I want a centrifugal operated advance.

That guy's second page of his article goes into fuel flow as one of the reasons stock lift pumps have issues supplying enough fuel. Short version is it needs bigger fuel lines.

Who's going to pony up and buy one of the $700 aftermarket pumps? That and both tanks full would double the value of my truck

 

[raydav]

I currently have six vehicles that run. My wife's 73 Mach 1/460 is the only one that still has a mechanical fuel pump. I built it almost two decades ago and all I have done to it since is repaint it.

The 01 PSD and 65 Mustang run 60# EFI fuel systems. That leaves two carbureted and the IDI which are low pressure supply systems.

To construct, test and later troubleshoot a fuel supply system, it must move fuel. If the pump is engine driven mechanical, then the engine must be running to test the fuel system and there must be a functioning fuel supply system for the engine to be able to run. Catch 22.

As for how good a pump an IDI requires. I run pumps thru a three way switch so that I can have it run when there is engine oil pressure, always or never. At least twice I have driven off with the supply pump off. My van weighs 9K#. I drove 50 MPH, three miles, flat ground. The IP pulled fuel thru a Racor filter and the supply pump. Some day I might turn the supply pump off on a hill to see what happens.

 

[Macrobb]

As for how good a pump an IDI requires. I run pumps thru a three way switch so that I can have it run when there is engine oil pressure, always or never. At least twice I have driven off with the supply pump off. My van weighs 9K#. I drove 50 MPH, three miles, flat ground. The IP pulled fuel thru a Racor filter and the supply pump. Some day I might turn the supply pump off on a hill to see what happens.

Yeah, if there is no air in the lines, the filter isn't clogged and there is no leaks... IP will pull fuel just fine. But, you'll run a hair retarded due to the lower inlet pressure on the IP.
I recall doing that with a mechanical pump too... I had the lift pump off the motor but still hooked up via flexible lines to the filter; I think I was swapping a cam at the time.
I went to test it... fired it up, and noticed that the pump wasn't actually in place... <_<.