Fuel supply pressure

[bgilbert]

Dyno, yes hopefully. Clutch, probly not. 6psi at wot I hope is better than 0. Might not be the answer for 500hp but we'll see I guess. Seems like those guys are looking for 10-11psi at wot. Maybe a newer cam would drive that piston LP better and give more pressure at wot?

 

[JLEONARD]

Plumb up an outboard engine squeeze ball in parallel... . and let GL be your copilot during the dyno run...

Bill gives the command... .

"SQUEEZE Scott... squeeze faster Scott..... come on we're only at 9 psi... :-laf :-laf " "More power Scotty. . "

 

[Jgolden]

Michigandon, what are you using for a transfer pump? My motorhome is a front engine 30' deal and even a little plugging on the electric (walbro) transfer pump filter screen at the tank had the thing pretty slow over the road. Never thought about fuel starvation until I read this thread. Crawled under and found the vent hose from the tank folded over, has to be better now. Need a fuel pressure gauge to check for sure.

Thanks to all here for helping me turn a dog into a moderatly

strong machine.

First gen info here has been outstanding.

 

[Stomp]

Fass

It looks to me that after my last dyno that my Carter supply pump is not working as well as I would like it to. Last time I checked the fuel pressure I had 15psi at idle and 10psi at WOT. Well I vapor locked it on my second run on the dyno. Quite embarrassing if you ask me. I plan on installing a Fass fuel system here in the next couple of weeks. I think that will take care of my supply problems. I will also be adding a permanent fuel pressure gauge while I am at it. I just don’t know where I can put it, but that is just a small detail. I will let every one know how it turns out for me. I will try to get some pic’s also.



Stomp

 

[cerberusiam]

This could be a problem when it comes to fuel delivery witha diaphram or piston pump:



#ad




I would guess a 1/4" ID line 8' feet long is going to introduce some flow problems especially when trying maintan 300cc injection events and enough fuel for lube.



From what I gather the 2nd gen p-pumps had larger lines and a larger tank pickup unit also.



The FASS or AirDog should help but the failure rates have me convinced there is just too much restriction with the factory lines to make big HP and not kill something.

 

[michigandon]

Jgolden, NO transfer pump. Just the lift pump on the engine. I have a 3/8" supply and a 5/16" return line and have had no problems (knock on wood!). No screen at the tank pickup itself. I do have a Racor 445R placed between the tank and the pump though, and I discovered that when the engine sound changes from a drone into a flutter, it's time to pull over and swap on a new element. One time the Racor clogged up and when I cralwed underneath to change it out I dicovered that the hose coming out of the Racor was FLAT . If the OEM pump is that powerful I can't wait to see how this piston pump performs.

 

[Greenleaf]

My P-Pumped engines use a rather large/wire braided/high pressure suction hose from tank to piston lift. I think 1/2" . The return line is 1/2" as well.



I'm not going to take time out to measure this but the high pressure lift pumps have a much larger pipe thread connection @ inlet than do our 1st gen truck piston and diaghram pumps do.



If you increased the line size on our trucks, you'd also have to drop the fuel tank and remedy the pick-up tube size.



Not impossible, however that isn't something I'm interested in doing unless it nets large returns.



GL