thetech

iTrader: (1)

I'm running a fuel cell so have no internal fuel-pump setup. On my old NA configuration I ran a single Walbro GSL392 which was plenty for the power. Now I am looking at making 500-600rwhp, so picked up an additional Walbro and am wondering what the best configuration would be for running two external pumps.

I had read somewhere that running them in series was very effective but can't seem to find any information to support that. This is for a 20B application with 3 x 1000cc primaries and 3 x 1600cc secondaries. Alternatively I could always feed each rail with 1 pump as my FPR has the ability to support 2 returns, but my concern is whether or not the Walbro can support the secondary rail well enough.

I also have a Bosch 044 I can substitute for one of the Walbro's if that helps, but am slightly confused on how fuel flow works with two pumps in series.

Thanks in advance!

crispeed

At minimum two Bosch 044's. Other than that look into a single Weldon 215 or Aeromotive 'Eliminator' fuel pumps.

thetech

iTrader: (1)

If I used two 044's, how would I configure them? One feeding each rail? Both in series?

Incidentally, I was talking to patman yesterday who just made 575rwhp/480rwtq (which is more than I am hoping to make). He is using two in-tank Walbro's Y'd together inside the tank with a single -6 to the rail. I'm basically looking to recreate this setup with the 2 Walbro externals that I have, if possible.

Ideally in the future I will use a single monster pump, but would like to figure out a good arrangement for these Walbro's because I have them already!

Jeff20B

iTrader: (13)

Try them parallel.

thetech

iTrader: (1)

Y out of the fuel cell and 1 into each rail?

rotaryengineering

When setting up the pumps to supply fuel do not run them in-line. I have heard several people on this forum make this recommendation which I believe makes no sense. Run 2 of the Bosch 044 pumps in parallel side-by-side. Each pump will support roughly 550 so if one pump burns out you always fuel supply to your injectors.

Here is how I ran a system similar to what you have described.
1. 2 separate fuel source inlet feeds from your fuel cell into the pumps. (usually -6AN from the fuel cell)
2. 2 separate Piersburg Fuel pumps in parallel out to a NOS Dual -6AN feed out to 1 -8AN main fuel supply to the front of the car. (Redundant fuel source for engine safety).

Talk to George at European Motorworks in Inglewood (310)644-8038. He has these fuel pumps in stock on the shelf.

Hope this helps.

FYI: Here is link to Cartech.net they sell similar type bolt-on units for their Pro 5.0 Turbocharged customers.
http://www.cartech.net/fuelsystems.htm

Albert

thetech

iTrader: (1)

Thanks for the tip. Just spoke to George and he recommended running them in series! Confusion builds!

Albert, in your suggestion above, are you saying Fuel cell outlet -> Y fitting -> 2 fuel pumps -> Y fitting -> -8 feed to primary rail?

BLUE TII

iTrader: (9)

The reason one would want to run the fuel pumps in series is that if you look at their flow charts they flow MUCH more fuel at lower pressures.

Running 2 pumps in series mean each one is only pumping against half the total fuel pressure system thus allowing much higher total flow.

This is going to be much more evident at the higher fuel pressures of a turbo car at high boost and the rising pressure regulator required.

Running them in parallel causes quite a bit of flow drop as the two pumps outlet flows merge, though obviously it works well enough.

Still, look at the European cars that use two fuel pumps and you will see they are in series.

I had 2 external Walbro pumps, fittings and mounts all ready and then did some research on actual flow numbers and amperage draw at the pressure I expected and bought a single Bosch '044 instead.

thetech

iTrader: (1)

Thanks, thats great information. I guess I'll give the Walbro's a shot and see what happens!

rotaryengineering

thetech,

Sorry for the confusion in my description I had to run to meeting and replied quickly to your question.

From the fuel cell there are usually 2 -6AN fittings coming out of the bottom. I used these 2 lines to supply fuel to each Bosch 044/Piersburg Fuel Pump. Then out of each pump 2 -6AN lines to a NOS Y 2 -6AN inlets to 1 -8AN outlet fuel supply to your fuel pressure regulator at the fuel rail.

Hope this was clear.

Albert