Are you trying to flow the Alaskan pipeline with all those pumps?


Steve

 

All those pumps will only increase pressure, not volume.

 

Talking about pumps, don't the intank pumps last longer because they are cooled by the gas in the tank? The 355 pumps you talk about, what brand are they and model #. Are they direct fit?

 

Yes they are direct fit and flow VOLUME... Bosch #0580254044.

 

I've been looking around on the internet and reading some stuff on fuel systems.

The pumps I have should support the HP I'm making. According to the calculations I found w/o nitrous I need about 250 liters/hour worth of fuel. Two Walbro pumps should get me to about 440 liters per hour at 70psi and 14 volts and 11 amps.
I don't know much about pressure drop and how much flow can go through the current fuel line and filter, but I'm sure that has some negative effect upon the amount of fuel delivered. Also maybe I'm not getting enough amps to the pumps. I think the power runs to the pumps in two lines then merges to one line just before it goes into the tank. That line is only about 14 gauge wire. Maybe that is not enough for the higher amps.
If one Walbro 255 @ 14volts 73 psi draws 11 amps and pumps 220 liters per hour. Will two pumps twice as much if the line is big enough and draw twice as much amps?

 

If it only peaks at 73 psi, i would say no.

But i suppose that depends on if you feed them independently to the left and right fuel rails.

 

Hehe, Im lovin this thread!

Scott

 

Easter
The last thing the fuel sees is the fuel pressure regulator. So if the regulator is set for 60 psi, then that is what all the injectors will see, even if the pumps have to push 100 psi to get the fuel there, the regulator returns fuel to the tank when the pressure reaches its pressure setting.

What I would watch on your system is what is happening on the fuel pressure gauge on a long hard pull.....at the top of 3rd gear.
If you have pressure drop off at that point then you have a pump problem, but if it still holds good pressure then the problem is elsewhere.

See my previous post where I mention slowing the fuel down with the larger fuel rails so it has a chance to feed number 4. There is a reason why I said that. And by the way # 4 is not the last injector to be fed....# 1 is. When you say #4, I assume you are talking about the passenger side squirter up against the firewall.
Dale

 

Hmmm, Mr. Freeze brings up a good point. Running 16#'s boost at wot could get you around 8 or 9#'s climbing a hill, with not that much throttle. Could be that things ARE leaning out at less than wot.


Mark

 

What I meant on the pressure is maybe the pumps are at 100psi and at the regulator it is 60psi due to the filter, line, etc. The Walbro 255HP only puts out maybe 100 liters per hour at 100psi. I think I figured I need about 250-275 liters per hour for my current setup w/o nitrous. That leaves me 50-75 liters per hour short of fuel.

I usually have at least 1/4 tank of gas. I wonder if that is not enough.

You are right about #4. It does look as if #1 is the last to get fuel.

 

Twin 255 pumps will support 1000hp,,,but our stock fuel lines wont....

 

easterisland
Funny you should mention the fuel tank....thats one thing that could be a big issue, some of these guys that are planning to put a cell in there truck could be on the right track.

The stock fuel tank is horrible when it comes to fuel control. Or to put it another way....if you have a 1/4 tank of gas and accelerate hard....like at the drag strip with slicks on, then you run a real risk of runnin the pumps dry for a second. There isn't much baffling inside the tank to hold the fuel around the pumps if the fuel were to slosh to the back of the tank.
I wish we had some side cut away pictures of a stock fuel tank, it would make this easier.
Dale

 

I ran into this same problem early 2002. Once we broke into the 10s, I kept melting the number 4 cylinder head chamber. It wasn't the injector, it wasn't the tune, it wasn't airflow, it was the rails. I burned the head about 4 times before I talked to my buddy Randy Haywood, whos suggested I lose the factory rails. I then went to 1/2 billet rails, 1/2 feed lines, external regulator, and I used the factory feed line as the return. I kept the dual 255s as I calculated their volume to about equal to a Weldon 2015. After doing the rails, never had an issue again.

For those interested in my setup (as I've been getting asked a lot lately) here it is...

Factory pump assy with twin 225s, going into a 1/2" Y bulkhead out the top of the fuel pump plate. Half inch hard line to an Aeromotive filter (which snaps right into the stock fuel filter holder). Braided 1/2" line up to a Y block behind the motor. Half inch feed lines into the back of EACH rail. Half inch return line out the front of each rail, going to each side of the regulator. The line out the bottom of the regulator goes to the factory feed line, which retuns the fuel to the tank. The factory return nipple on the tank is capped off.

Hope this helps.

 

Sal, can you make up that same kit and sell it to me.....Pete

 

ditto...