Dual Walbros: Let Me Know What You Think

[xlMcMlx DsM]

^^^ Many guys (myself included) have two pumps running at all times. If each one was on it's own relay and one relay failed, it could be catastrophic in a high pressure situation. If they share a relay and the relay fails, the car shuts off.

If your one single relay is large enough, there won't be any problems. I have a Denso 280LPH and a Bosch 044 running through a 40 amp relay and I have no issues. I'll probably bump it to a 60 amp this winter just for added piece of mind, but to my surprise, the 40-amp has been doing it's job just fine.

Exactly. Two pumps=wired to a SINGLE relay. You want both pumps to die if something happens. Rather than be at 7500rpm, and one pumps dies, you run lean, BOOM. The 2nd setup looks good! And nice numbers!

 

[____Kurt____]

Whats the best way to wire the pumps through the cover? Fittings, wires, connectors etc....

 

[99gst_racer]

Whats the best way to wire the pumps through the cover? Fittings, wires, connectors etc....

See about halfway down: http://www.dsmtuners.com/forums/bolt-tech/413571-255-walbro-necessary-rewire-my-setup.html

 

[____Kurt____]

See about halfway down: http://www.dsmtuners.com/forums/bolt-tech/413571-255-walbro-necessary-rewire-my-setup.html

Thanks Paul! Thats thinking outside the box , p.s. what pump is that?. I'm trying to get a list together so I know everything I need to order all at once and make sure Its all the right parts.
So far I got bulk heads
Not sure what "Liquid-Tight Cord Grip" yet
Any wire can be exposed to gas?
I appreciate any help given and I figure I post up my questions it might help others.

 

[99gst_racer]

Thanks Paul! Thats thinking outside the box , p.s. what pump is that?. I'm trying to get a list together so I know everything I need to order all at once and make sure Its all the right parts.
So far I got bulk heads
Not sure what "Liquid-Tight Cord Grip" yet
Any wire can be exposed to gas?
I appreciate any help given and I figure I post up my questions it might help others.

No problem. That was a Denso pump for the TT Supra. I assume most wire can be exposed to fuel. The stuff I used was regular car audio power wire and I never had any issues with it.

 

[____Kurt____]

No problem. That was a Denso pump for the TT Supra. I assume most wire can be exposed to fuel. The stuff I used was regular car audio power wire and I never had any issues with it.

This is 6ga wire? Also from this site it looks like you used the nickel plated brass?
Thanks again Paul!
McMaster-Carr

 

[____Kurt____]

So back to this. I finally got all the things (I hope) that I need to run 2 Walbro 255 pumps from in the tank up to the rail and back to the tank (return). I am looking at a lot of peoples pictures of how they mounted the pumps and ran the wires. My question is, how are people running the wires from the pumps through the sending unit cover and keeping a seal. I did post about those liquid tight fittings but I don't see anyone else using them and I would like to know what it is. Thanks

 

[leepen]

I used this gromet and BLK RTV per vfaqs (RTV only not the gromet)

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not cleaned up yet

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seems to have sealed, but is mushy on my 450 and will run the ground to one of the cannester bolts

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[____Kurt____]

Thank you that gives me some help but are you suggesting to use a gromet with the RTV? Where would I be able to find fuel safe gromets? Also is that submersible fuel line you are running?

 

[leepen]

Thank you that gives me some help but are you suggesting to use a gromet with the RTV? Where would I be able to find fuel safe gromets? Also is that submersible fuel line you are running?

Its fuel line, is there a differience, looks the same as the line that came with the pump. Im not suggesting anything, just what Im trying...the vfaqs says use JB weld or RTV to fill the holes, mines just a bigger hole
4th picture down after the relay
Visual Frequently Answered Questions - Home Page
click fuel, then first post for 1gs fuel pump rewire
FYI my tank will never be full, so wasnt really worried about fuel safe gromets

 

[99gst_racer]

This is 6ga wire? Also from this site it looks like you used the nickel plated brass?
Thanks again Paul!
McMaster-Carr

Sorry for the late reply - just now seeing this.

I believe I used 8 or 10 gauge wire. It was way bigger than I needed, but it was what I had laying around. And yes, I used the nickel plates brass liquid tight cord grips. They worked perfectly for me, so I'd recommend them to anyone.

FYI: I tried the grommet/RTV method before the cord grips. With a full tank, the fuel would reach the pump assembly and it eventually softened the RTV and caused it to leak. It also didn't help that there was no positive wire retention. I wasn't too excited to find fuel leaking onto my exhaust. The cord grips really are the best solution that I've ever found for this application.

 

[____Kurt____]

Well I was talking to a friend that did dual pumps and told me what he did was he made bulk head bolts and ran a nylon washer to seal it. Then he bolted the wires on the outside and inside using ring connectors. Similar to factory setup but bigger bolts. How does this sound as a solution?

 

[leepen]

This is the top of the canister lid, see the dark octagon ring around the brass. Its a hard plastic/rubber. All but the ground have this.

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This is the stud

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So Kurt, it looks like you will have to make sure all the bolt are not touching the canister top, except the ground

 

[TSimage]

If you want to retain the fuel level/fuel gauge, don't do it like the OP.. His design was simply flawed because he modified the hanger and you don't have to. If he would have shortened his setup he could have ran them on the same side.

My 3065 setup utilized dual 255s but my HX40 setup used dual Aero Stealth 340 pumps. I am running a larger single relay and the wires are ran just like OEM and not a single issue has ever been had. No need to drill any holes for wires...

 

[____Kurt____]

Ok back to this, So the pumps are all installed and now is just for me to finish the wiring. I read an article about a dual fuel pump install and wiring and it said to use 2 relays which made sense to me at the time because there are 2 pumps. But now thinking about it I have both pumps intank hooked up to the same bolt that I will be supplying power to. Out side of the tank is power stud for both pumps. So no I will only be running 1 relay instead of 2. I wish I thought this through completely because I bought everything I needed to make 2 separate power sources. I will be running a 10g wire from the battery with a resettable fuse to the relay, then to the power stud. So if anything fails it will turn off both pumps and kill the car completely, no chance of running lean under boost. Does this make sense to everyone?

 

[keltalon]

I will be doing this soon. Thanks guys.