Dual Walbro's in a 1G AWD
 

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.
http://www.mitsustyle.com/photopost/...m/IMG_1027.jpg


- 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.
http://www.mitsustyle.com/photopost/...m/IMG_1029.jpg

- With the fuel line disconnected, using an 8mm socket, remove the 6 nuts holding the fuel sending unit down.
http://www.mitsustyle.com/photopost/...m/IMG_1030.jpg

- Remove the fuel sending unit
http://www.mitsustyle.com/photopost/...m/IMG_1031.jpg

- 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.
http://www.mitsustyle.com/photopost/.../IMG_10342.JPG

- 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.
http://www.mitsustyle.com/photopost/...m/IMG_1036.jpg

- Reinstall the fuel pump assembly. It is all simply the reverse of the removal.
http://www.mitsustyle.com/photopost/...m/IMG_1038.jpg



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.

Re: Dual Walbro's in a 1G AWD
 

Nice write up, did you reuse your strainer?

Re: Dual Walbro's in a 1G AWD
 

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.

Re: Dual Walbro's in a 1G AWD
 

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

Re: Dual Walbro's in a 1G AWD
 

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

Re: Dual Walbro's in a 1G AWD
 

Good info brandon!

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

Re: Dual Walbro's in a 1G AWD
 

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

Re: Dual Walbro's in a 1G AWD
 

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.

Re: Dual Walbro's in a 1G AWD
 

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.

Re: Dual Walbro's in a 1G AWD
 

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

Re: Dual Walbro's in a 1G AWD
 

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

Re: Dual Walbro's in a 1G AWD
 

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?

Re: Dual Walbro's in a 1G AWD
 

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.

Re: Dual Walbro's in a 1G AWD
 

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.

Re: Dual Walbro's in a 1G AWD
 

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.

Re: Dual Walbro's in a 1G AWD
 

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.

Re: Dual Walbro's in a 1G AWD
 

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 :(

Re: Dual Walbro's in a 1G AWD
 

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.

Re: Dual Walbro's in a 1G AWD
 

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

Re: Dual Walbro's in a 1G AWD
 

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?

Re: Dual Walbro's in a 1G AWD
 

By the part# on it. The 3 most commonly found families are the 190lph, 255lph, and the 255lph HP. You almost always want the 255lph HP on a DSM that is going to run decent amounts of boost. Each family will usually have 3-4 different variants of the pump. Like the GSS341, GSS342, GSS340 and GSL392 are all different versions of the Walbro 255lph HP, with different setups for the inlet/outlet for different cars. The is a 190lph HP also, but I have never seen one. There are also China/eBay knockoffs that are hard to tell from real ones.

Re: Dual Walbro's in a 1G AWD
 

What i would like to know is that how much is too much for those small ass fuel lines. I dont think i would do this mod unless i have upgraded my fuel lines to bigger ones from the fuel pump all the way to the rail. But thats me personally.
And i would definatly agree with the rewire. Its cheap and simple. I run mine directly to the battery. (which is only 3 ft from the fuel pump.)

Re: Dual Walbro's in a 1G AWD
 

WHY HAVEN'T I DONE THIS MOD YET!!!

i have a spare 255 sitting in my garage and my fuel pump is already rewired

I will be posting pictures later of mine later and how this will turn out

good write up and pictures are worth a thousand words!

Re: Dual Walbro's in a 1G AWD
 

The way I see it, why push the stock wiring and hope it works (especially w/ something so important as fuel pressure), when a re-wire really isn't that difficult anyways and then you'll KNOW that you'll be alright. JUst my .02

Re: Dual Walbro's in a 1G AWD
 

Hey, is there a good place to find this submersible fuel line, I went to the parts store today and they all gave me funny looks.

One store asked what I was going to do with it and when I told them, they replied "sir, everyone else here is trying to save fuel and you are the only one trying to burn more of it" Thought it was kind of funny:fart2:

Re: Dual Walbro's in a 1G AWD
 

Well, it says Napa in his post. I would try there.:) DB is in Rogers so the Napa in Rogers is probably even a safer bet.

Re: Dual Walbro's in a 1G AWD
 

I read somewhere you don't even need dual fuel pumps, it's actually better to up the voltage to 17volts to the single pump with some type of amplifier. apparently even a stocker pump will get better flow then dual pumps when you do this, am I talking out of my ass or is this true?

Re: Dual Walbro's in a 1G AWD
 

I'm gonna go w/ the ass talking option

Re: Dual Walbro's in a 1G AWD
 

+1, ass talking. It's been shown several times actually that those boost-a-pump devices help, but are immediately out-flown by twin pumps.

Re: Dual Walbro's in a 1G AWD
 

Ah-ha, good to know the facts.

Re: Dual Walbro's in a 1G AWD
 

I will be picking up a relay and doing a rewire if I get the car back this weekend. I'll make sure to take pics and add it all to the 1st post.