Bout to get my s-10 project on the road. Heres the specs.

Stock 5.3 lm7 w/ 317 heads
s-475
96lb injectors
Stock pump in tank to 1 gal surge tank to a single Walbro 255lph. -8 line
Megasquirt 3 Tuned

Tuning on 5psi it pulls good and has great Afr thru the range. When i step it up to 12psi or so its running out of fuel and running lean so i have to let out. No matter how much we fatten the tune up under boost its still starving. Am i right thinking that the little single Walbro is maxed out already? Planned on running dual 255's later when i got cam and springs and stepped it up to 25psi or so. But didnt think id run out of fuel pump so soon. Any other suggestions on what it might be before i order all the stuff to do Duals? Or should i just go ahead and do it.? Thanks for your help fellas.

 

Fuel pressure gauge will tell you if it's losing fuel pressure.

 

If the stock pump is just running to a surge tank, then you're just running off of the single 255. So you could be dropping fuel pressure because of not enough pump.

 

Dont have a Fuel pressure gauge yet. Not got around to it. So dont know if its dropping or not. I can monitor just about everything but fuel and oil pressure thru the Megasquirt. Real gauges to come soon tho. Speedo would be helpful. lol

Im gonna be spraying a little also when it gets taken to the track and adding water/meth soon. So Will the dual Walbros support my fuel needs for this set up or should i look into a different set up? Whats the HP limits to a dual Walbro 255 set up?

 

i can guarentee you its not enough pump...... spend the extra money and get you a good fuel pump because all your going to do is upgrade from here on out, get the nice A1000 pro pump or a beast weldon if you have the cash

 

^that.

Get a good single pump instead of running 10 little guys.

 

I love my aeromotive A-1000 setup..

 

Well i've already got another Walbro i can scavenge from another project. So all id have to buy is the Fuel line and some AN fittings. I really didnt expect to be out of pump on only 12psi.
But maybe later on down the road drop the coin on a nice fuel set up when i go to fuel cell and 4 link and all that. Right now im just trying to get it going and on the road with a good tune and pretty decent power. What are the disadvantges to dual walbro's seeing that i already have them.?

 

12# is probably pushing the 255 past its limits. thats where i start running out w/my 4.8 on 12#. did i read you are going to up boost to 25#? poor little 5.3!

 

Just have the second pump turn on with a Hobbs switch. Don't run both all the time. I run a stock pump with a walbro coming on for anything over 5psi. You may even be able to activate a second pump with MS.