Dual Intake Walbro Wiring? (E85) Safe?

[BoostedBeaver]

In the past few days I have revamped my fuel system to quench the thirst of e-85 During the process I have installed dual walbro 255 HP's to the stock hanger. I used two -6an bulkhead fittings on top of the sending unit. These two -6an lines feed a Y (outside the tank) that goes to a single -8an line to the rail.

Anyway the Walbro wiring harness is made to ground inside the tank and has a short ground wire. I was going to run the wires out of the sending unit and to a chassis ground with a 10AWG wire. It may not be needed but drawing 20+ amps it couldn't hurt. So here is the question, How safe is it to solder the two grounds to a single 10AWG wire inside the tank (E-85)? This would be covered by one (two if possible) pieces of shrink tubing although I do not know how it will hold up against the E-85. Would this be the most ideal and safest way to run the wiring?? I just do not like the idea of the wire shorting out inside the tank!!!!

I have read a lot and it all seems to point to the fumes of gas and needing oxygen to explode but what about ethanol???? Just trying to be as safe as possible when it comes to electricity inside the fuel tank. Recommendations for other possible solutions as well as improvements to my current method are greatly appreciated. Thank you in advance for your advice and I will be posting a video of the entire install once this part is completed.

Robert

 

[turboglenn]

You won't be in any danger once the soldering is complete (as long as it's not a loose connection tossing sparks everytime you hit a bump anyway)
E85 is actually less flammable than gasoline (well in a way, it has gas in it, but alcohol fumes are less likely to ignite than pure petrol fumes)

Personally I had issues wth running 2 pumps on one relay in the past (actually was popping fueses but went through relays pretty fast too)

I wired mine to a singe ground outside of the tank, but each pump has it's own 30amp relay firing it off. Relay #2 for pump #2 is triggered off the power coming from the primary relay that the ECU activates (just to keep the ECU seeing the minimal load of one relay) Also each relay/pump has it's own dedicated 10 gauge wire and fuse block.

It's super easy to run an external ground (probably easier than the in-tank one) but then again i made my own pump hanger and all so it was e3asy to just have the extra hole in the top for the grounds

 

[BoostedBeaver]

Thank you turboglenn. It is nice to hear that from a member such as yourself.

I too worried about the one relay for feeding both pumps.WTF I guess I will give the one relay a try and if it burns the relay, I will run another 10AWG wire with another inline fuse to another relay that will be powered on by the main relay.

For the wires coming through the unit I used two rubber grommets that made a tight fit. I drilled 1/4in holes and inserted the grommets. It makes a snug fit for 10AWG wire and a tight fit for the two power wires. I attached a image and both power wires come up through the left grommet and the single 10AWG comes through the right grommet.

I really appreciate your input and I will keep the second relay in mind.

Robert

(Of course the AN bulkheads are not tight in this picture and are only being used to mock up fitment of the grommets and other various pieces)

 

[turboglenn]

Looks like youve done a great job on putting it together.. The problem i had with the relay is that after many succesfull pulls with both pumps sometimes after i wouls shut down the relay would "stick" and woulsn't fire off to power the pumps so i could get back home in my DD, so i'd have to pull the seat (my relays under rear seat) and pull up the panel, grab the relays and shake it or tap on it untill it would unstick, and sometimes it would burnm the 30 amp fuse.. after going to dedicated fuse and relay per pump i haven't been stranded out shopping again

let me knoiw how it works for you, I may have jsut been using cheap relays

 

[97gst_spyder]

So you can use normal wire in the fuel tank for the fuel pump cables? Also, I noticed that the contacts are bare open to gas to touch, so theres no need to cover the terminals?

 

[BoostedBeaver]

@ turboglenn I have heard many success stories using a 40 amp relay with a 40 amp fuse. Do you see any real drawback to using the larger amp relay??? Also, I will keep you posted on how long the relay/fuse life tends to be. If it matter the relays are from Radio shack.

@ 97gst_spyder I do not know if I totally understand your question but I will try to answer it. For the power wires, there was a rubber boot that went around the connection inside the tank. As for the fuel level sending unit, mine has always been bare.

 

[mike96]

So you can use normal wire in the fuel tank for the fuel pump cables? Also, I noticed that the contacts are bare open to gas to touch, so theres no need to cover the terminals?

As much as it doesn’t sound like a good thing, yes you can have bare contacts showing in fuel... Fuel actually doesn’t conduct electricity like water does. The only time you would really have an issue is if your bare wire/contacts are close enough together to make contact and cause a spark. But I don’t think even then you would have too much to worry about because you still need oxygen in the mix to cause the fuel vapors to burn and I doubt there is enough oxygen in your fuel tank to sustain a fire long enough to do any damage..... But precautions are good just make sure you seal up whatever grommets are there to pass wire thru so that they don’t leak and can handle a little pressure.

 

[97gst_spyder]

Thanks for the answers!!!! This is why I love this forum!

To the Op, sorry for thread jacking.

 

[turboglenn]

@ turboglenn I have heard many success stories using a 40 amp relay with a 40 amp fuse. Do you see any real drawback to using the larger amp relay??? Also, I will keep you posted on how long the relay/fuse life tends to be. If it matter the relays are from Radio shack.

@ 97gst_spyder I do not know if I totally understand your question but I will try to answer it. For the power wires, there was a rubber boot that went around the connection inside the tank. As for the fuel level sending unit, mine has always been bare.

I don't se any dwarbacks to a 40amp relay at all, I was using old 30amp units simply because that's what i had laying arounf,, I was using the larger standar size relay you see at the parts stores at first, but after raiding an eclipse and a few other mitsu car' for their fuses and relays at the junk yard i then soldered up a fwe of the mitsu ones that are silmmer and in general smaller in size, runnign one per pump and having no issues as all, you should be good to go as well, have fun!

 

[BoostedBeaver]

Thanks Turboglenn. I will let you know how it works out. I plan too have massive amounts of fun and hope you do the same.

 

[Calan]

In most cases, the only drawback with running a larger relay is that it may put more of a load on whatever is driving it, depending on the current draw of it's coil. There may also be an issue based on "make before break" (or vice versa) requirements of the contacts, but that wouldn't apply in this case.

As long as the coil doesn't draw more current than can be safely supplied, it should be fine. Use a fuse rated slightly below the current source's maximum output, and a relay rated higher than the fuse, and you should be golden.

 

[BoostedBeaver]

Calan, Thanks for the reply. I am feeding the relay from the battery with a 10AWG wire with a 35 amp inline fuse (6-8 in off the battery post) to a 40 amp relay in the hatch. If I understand your post correctly, this is ideal and I will be good to go. Thanks again for the input.

 

[turboglenn]

Using the stock fuel pump power feed wire to trip the relays would give you enough current to sink two HUGE relays so you don't have to worry about that part (but you do have to remember there's a relay in the stock system firing your relay in case you ever need to troubleshoot a non-running pump)

 

[BoostedBeaver]

Thanks turboglenn

That is a very valid troubleshooting point and some good resourceful information for others. Thanks again.

 

[Calan]

Using the stock fuel pump power feed wire to trip the relays would give you enough current to sink two HUGE relays so you don't have to worry about that part

Yeah... I'm pretty sure two relay coils would draw slightly less than the 10-20 amps that a fuel pump would...unless they were really, REALLY big relays.