Dual Walbro's in a 1G AWD

**Halon** · 05-12-2008

For anyone wanting to install dual Walbro's in-tank, in parallel, into a 1G AWD, here is a quick rundown of how my install went.

Performed on a 91 TSi AWD using dual Walbro 255HP pumps.

- Pump is located in the rear hatch on the drivers side. Begin by removing the electrical plug, and the 2 screws holding the black cover down.

- Next, using a 14mm flare wrench (important because using a standard open end wrench may cause you to strip the fitting), disconnect the fuel feed line.

- With the fuel line disconnected, using an 8mm socket, remove the 6 nuts holding the fuel sending unit down.

- Remove the fuel sending unit

- I had a second fuel sending unit as my original one had a broken power terminal. Cut approximately where the red lines are. This simply allowed the pumps to sit a little nicer against the sending unit. And cutting the output tube will allow you to attach a normal fuel line to it.

- Attach a Y (I just used a barbed T from Ace), and attach high pressure fuel line with clamps. Clamp the fuel pumps to the fuel sending unit using a worm clamp. You can use 2 if you don't feel that 1 is enough. Land both the ground wires at the grounding point on the fuel sending unit. Land both the positive wires to the power stud on the bottom of the top plate.

- Reinstall the fuel pump assembly. It is all simply the reverse of the removal.

That is all. Thanks to various others who helped me with this. If there is anything you think I should have done different please let me know. Hopefully this will be useful to someday else at some point in time.

DSM_421 · 05-13-2008

Nice write up, did you reuse your strainer?

**Shane@DBPerformance** · 05-13-2008

Did you use submersible fuel line? The normal high pressure EFI fuel line and SS braided lines doesn't like fuel on the outside of it and eventually fails. The line that comes with Walbro kits is submersible or you can get 1 foot sections from Napa.

**Shane@DBPerformance** · 05-13-2008

Do you have any upgraded wiring/relays/fuses powering both those pumps?

**Halon** · 05-13-2008

Quote:

Originally Posted by ecoli

Do you have any upgraded wiring/relays/fuses powering both those pumps?

No wiring changes. Is this something I need to be concerned about?

**scheides** · 05-13-2008

Good info brandon!

In this situation where both pumps are always on, is an aftermarket FPR necessary?

TkrPerformance · 05-13-2008

very nice the same way craig and steve has it done. I would do a pump rewire on them also

**Halon** · 05-13-2008

I prefer to keep this as simple as possible which is the main reason I didn't rewire it. I shouldn't need a rewire for more voltage, because with 2 pumps it should be able to supply plenty of fuel even at 12V. But if I need a rewire because of Amperage, then I will definitely consider it. Any input is welcome and appreciated. I couldn't find a How To on this really, so I just went off what I could find and I never found any thing anywhere mentioning issues with amperage, but I'm open to hear anything anyone has to say.

**Halon** · 05-13-2008

Quote:

Originally Posted by scheides

Good info brandon!

In this situation where both pumps are always on, is an aftermarket FPR necessary?

I would say yes. With 2 you'd more then likely outflow the stock FPR. And on a 1G AWD, the rest of the stock fuel return system after the AFPR should easily be able to handle the 2 pumps. No need to upgrade that.

AwdGSX13 · 05-13-2008

i was always curious how this was done, good write up.

95talonracer · 05-13-2008

Good information. Is doing a 2g awd similar? Anyone have a link for a 2g setup?

**Halon** · 05-13-2008

I started researching into if there is an amerage issue with running dual pumps off the stock wiring. I believe the MPI fuse is a 20A fuse. On RRE's site they show at 73 psi, the pump is drawing 10.5 amps. Double that for 2 pumps. Now I'm wondering, does that MPI fuse directly feed the fuel pump? If so then at full boost I have a good chance of popping that fuse. But if that fuse is just for the MPI relay, and the fuel pump feed is actually coming through different leads on that relay or something, meaning that 20A fuse isn't in the direct path of the fuel pumps, then I shouldn't have a concern with that 20A fuse.

Anyone who knows a lot more about this then me care to chime in?

iceminion · 05-13-2008

I have seen several people do this with stock wires, no problems or blown fuese to report as of yet.

My galant and my buddies talon will outrun the single 255's we have in there pretty soon.

When we switch over to the 2x pump system, if i have any problems ill post up here.

**Halon** · 05-13-2008

You've seen several people run the dual Walbro's on the stock wiring? What kind of fuel pressure are they at at full boost?

The thing I'm worried about is in fact blowing that fuse. If I get my fuel pressure up to around 70psi and the amp draw is too much, that's really not a good time for my fuel pumps to lose power.

A//// Guy · 05-13-2008

The problem with the stock wiring is that it doesnt supply enough voltage when you upgrade pumps. So upgrading to two pumps would help but you are drawing even more power on the stock wiring. I think thats a bad idea.

I would upgrade to thicker wiring, add a relay and a larger fuse.

**Goat Blower** · 05-13-2008

If you remember a long time ago, people were seeing a noticeable difference in fuel flow just rewiring any single fuel pump, and that's when using a 190lph pump was an upgrade and the 255lph was considered a race car mod. Mine's been upgraded since 1997, so putting in two pumps, I didn't really need to upgrade. I definitely would if you're on stock wiring. I might even upgrade mine directly to the battery instead of the FP relay.

**Halon** · 05-13-2008

Yes I understand by rewiring, you may see an extra 2 volts or so at the fuel pump, allowing it to flow more. I did this on my old 2G 7 years back. It's a great mod if you are pushing the pump. But do you think I'm going to need those extra 2V in this case? Am I going to require more then what 2 255hp's put out at 12V? I honestly don't think so. Guys have ran SC61's pushing a single 255 to it's limits. 2 255's won't flow double, but will flow quite a bit more then a single. As of right now I really don't think I need to rewire this because I need that extra 2V for more flow. But again, what about amperage? Adding a 2nd pump just doubled the amperage the stock wiring will be seeing. That's what I'm worried about, too much amperage on the stock wires. I may just end up rewiring it because I don't want to pop a fuse and lose power to the pumps during a 30psi pull. That'd make for a real bad day

Kevin 1G Drummer · 05-13-2008

I'd say just rewire it and be safe. There's no sense in worrying about too much amperage when you alredy know how to prevent it.

DSM_421 · 05-13-2008

Damnit kevin, you need to fix that quote in your signature...

joesushi · 05-20-2008

Is there an easy way of identifying a 190 vs a 255? I don't know which one i have. I can only assume running a 190 with a 255 is not on the safe side, right?