Dual Tanks, Anyone Using TBI Pumps to Feed Single Walbro In-Line Pump for LS Swap?

[Ford Assassin]

Any reason this wouldn't work on my TBI/454 1988 R30 for my 5.3 swap? I have done well over 25+ LS swaps, but never had to deal with two tanks,

Here's the paper napkin plan:

Each in-tank TBI pump (both new Delco pumps 7 months ago), through the factory fuel lines to the stock tank switch valve, then valve would feed into the high pressure pump (Walbro 255 in-line that I already own, just need to splice in), then into a
Wix 33737 Corvette style filter/regulator (and fuel return plumbed back into the factory/stock fuel lines, through the switch valve), lastly to the 2005 returnless the fuel rail inlet.

This would be the least expensive route for me since I already own everything from a previous project combined with the factory TBI fuel system. Easiest too from a labor stand point.


Thanks.

[Ford Assassin]

41 views and not a single person has a comment? No way I am the first guy to think of this.

What happened to this board? 10 years ago it was full of members that were eager to help and learn, now it's lurker central. No wonder people just message me directly instead of posting their questions in the forum.

[mongocanfly]

Ok I'll play....never done it or seen it done...but the walbro is more than capable of pulling from either tank on its own....I've never seen anybody force feed a walbro...might want to contact walbro and ask what the consequences are of pressuring the pump inlet...I'm assuming the reg will return to the tank your pulling from thru the switch valve..correct?

[Ford Assassin]

Originally Posted by mongocanfly

Ok I'll play....never done it or seen it done...but the walbro is more than capable of pulling from either tank on its own....I've never seen anybody force feed a walbro...might want to contact walbro and ask what the consequences are of pressuring the pump inlet...I'm assuming the reg will return to the tank your pulling from thru the switch valve..correct?

Thanks for the response. I have run dual walbro 255's in series before with turbo setups in factory LS platforms with no ill results.

Correct, the Wix 33737 filter regulator will return the fuel in the same fashion the TBI system would. The tank selector valve not only pulls from the selected tank (and turns on the pump in the same tank), it also directs the returning fuel back to the same selected tank.

[mongocanfly]

If youve run 255s in series with no problems,then I don't see were youll have a issue with what your wanting to do...although I don't really see the need to feed the 255 with another pump...but if it works,it works

[Ford Assassin]

Originally Posted by mongocanfly

If youve run 255s in series with no problems,then I don't see were youll have a issue with what your wanting to do...although I don't really see the need to feed the 255 with another pump...but if it works,it works

Unfortunately the stock TBI pump won't make nearly enough pressure for LS fuel system.

[dayj1]

Originally Posted by Ford Assassin

Any reason this wouldn't work on my TBI/454 1988 R30 for my 5.3 swap? I have done well over 25+ LS swaps, but never had to deal with two tanks,

Here's the paper napkin plan:

Each in-tank TBI pump (both new Delco pumps 7 months ago), through the factory fuel lines to the stock tank switch valve, then valve would feed into the high pressure pump (Walbro 255 in-line that I already own, just need to splice in), then into a
Wix 33737 Corvette style filter/regulator (and fuel return plumbed back into the factory/stock fuel lines, through the switch valve), lastly to the 2005 returnless the fuel rail inlet.

This would be the least expensive route for me since I already own everything from a previous project combined with the factory TBI fuel system. Easiest too from a labor stand point.


Thanks.

I would say that it won’t work. At least not for very long. To explain why, you have to understand that pumps don’t create pressure, pumps create flow. You didn’t say which TBI pump that you’re running, but even the highest flowing TBI factory pumps flow in the neighborhood of 120 lph. The walbro 255 flows 255 lph, so you’d be starving the Walbro pump for fuel.

This is from the Aeromotive web site:

WARNING: Combining pumps “in series” that have substantially different flow curves is not a good idea and will probably create more problems than it solves. For example, trying feed an A1000 with a stock fuel pump in the tank would starve and damage the A1000. A good rule of thumb to avoid problems would be to combine pumps with a differential flow of no more than 10-20%.

https://aeromotiveinc.com/tech-help/...fi-fuel-pumps/

[mongocanfly]

yeah I'm aware of the tbi not building enough pressure....I was saying I don't see the need to run the tbi pump into the 255 pump..my 255 pump works great by itself
was there a reason you were wanting to run the tbi pump into the 255?

[Ford Assassin]

Originally Posted by mongocanfly

yeah I'm aware of the tbi not building enough pressure....I was saying I don't see the need to run the tbi pump into the 255 pump..my 255 pump works great by itself

Oh okay, my mistake. I am sure you are right. Done many LS swaps using a single Walbro 255 or Bosch 044 in line for myself and customers.