crashmymax

iTrader: (1)

I have an 09 flex silverado that I am going to put dual pumps in. Looks like there's plenty of threads on how to do it. One thing I am trying to figure out is why some guys have issues with fueling below half tank? Is it the way they install the pumps in the bucket that causes this? I need to avoid this. I am running e85 and only have one station in town that carries it. Filling up at half a tank would not work . Anyone no the cause and if it will be an issue with my truck? Will be going to a return style. Thanks

mcfarlnd

iTrader: (15)

The only issue is retaining the Venturi system to keep the bucket full. When most go to dual, they cut up the bucket to get fuel to the pumps but, fuel just runs out of it when you hammer down the throttle. You could definitely fit two pumps in there if you rid of the big filter assy. Then you could run the second pump on a Hobbs or "Y" it in to the mainline. I put a bunch of pics in my write up. Although only a single pump configuration, you could probably get a great idea of what you can do. Also, remember, there is a check valve after the pump in the Venturi to prevent pressure loss when turning the truck off. If you don't have a check valve on the Venturi, you will have 0 psi in the line by the time you start your truck after it sits for about 30min causing long starts while the pressure tries to build back up.

crashmymax

iTrader: (1)

Hey thanks for the reply I read through your thread. Why did you stay returnless? My truck is an 09 flex so same sending unit you used. I may send you a pm or 2 for help when I start moding the unit.

Atomic

iTrader: (42)

Most newer aftermarket pumps have internal check valves, so you shouldnt have to worry about loosing prime that easily (the walbro 400s and 450 do anyway).

Do not cut the outer bucket, leave it intact. You can drive below half a tank, just dont go ape **** doing hard accelerations. Generally if you leave the bucket intact and have the return (yes even returnless systems have a "return") going inside the bucket you should be ok to 1/4 tank or so.

crashmymax

iTrader: (1)

Ok sounds good. What do you think of dual 450's ? I think I will be looking for 7-800 rwhp with the new engine. Want to make sure fuel will not be an issue. Going to do -8 feed. -6 or stock feed for return. I have some fuel rails on the way. What is a good quality regulator to use?

Atomic

iTrader: (42)

If you are using E85 dual 450s is a good place to start. I like aeromotive or magnafuel regulators personally.

crashmymax

iTrader: (1)

I think I will be staying with e85. Will 450's support 800 or should I go with something else? Guessing the 80lbs injectors wont be enough on e85. What should I go up to?

Atomic

iTrader: (42)

Yea 2 450s will be enough pump, but for injectors I would go with at least 127lb@4bar. Maybe 160s if you plan for that eventual 1000rwhp like everyone does

crashmymax

iTrader: (1)

160 is a big injector. Can you make them behave on the street at idle?

Atomic

iTrader: (42)

Yep, not a problem with the modern bosch or ID injectors. Give Jon at FIC a call and he will get you fixed up. IDs are great, just so overpriced IMO.