long travel Outbacks or making Subarus faster and more reliable offroad

[pontoontodd]

B and I worked on the secondary fuel tank for the Impreza.  I pressure tested it and flushed it out, seems like it doesn't have any leaks even at 30psi.  I got the mounting flaps carved up so it fits and matched up the bumper mount holes. 

We had to do a little more hammering in the spare tire well. 

We came up with a plan on how we want to mount the fuel pumps and run the hoses.  I need to get another pump, some hoses and fittings.  Going to try to get wire connectors for the ABS wires so we can use those for the fuel pumps since they're already running front to back and will never be used for ABS again.

B replaced the cabin air filter and cleaned out the airbox and blower fan, they were all loaded with debris.

He also traced the brake lines under the hood and we came up with a plan on eliminating the ABS module and plumbing the left/right steering brake from the black Outback.

[slammo]

You think those ABS signal wires are heavy enough to run a fuel pump, or are you just using them to trigger a relay?

Good thing you have a cabin air filter.

[pontoontodd]

5 minutes ago, slammo said:

You think those ABS signal wires are heavy enough to run a fuel pump, or are you just using them to trigger a relay?

Good thing you have a cabin air filter.

Good point I'll take a look at the gauge of those wires.  Won't be under much pressure so according to the internet it'll draw 4-5 amps and even 22 gauge wire should be adequate.  Definitely not getting any relays involved.

Thanks again for the cabin air filter tip.  We were discussing how full of junk the evaporator would be without it.  Like the one on the black Outback was.

[slammo]

If you're planning on using a full-pressure fuel pump to deliver to the engine bay, the ABS wiring definitely won't be adequate. Plenty of people say the stock fuel pump wiring isn't adequate lol. But if you're just using a transfer pump to move from aux to main tank, maybe the current draw will be low enough.

[el_freddo]

I’d set it up as an aux Fawcett pump to transfer fuel from the aux tank to the main tank. Far simpler than trying to run a second high pressure pump and work out valves/relays to switch fuel lines to avoid back feeding and sort out the redirection of the returning fuel (unless you run a deadhead setup with zero fuel return). 

This sort of thing is something I want to do with my brumby under the tray behind the cab where there’s a decent cavity. 

[Numbchux]

Personally, I don't think I would trust ABS wires. Small gauge, and twisted pairs. Maybe use all 4 rear ABS sensor wires as positives, and then ground to the body

Using this calculator, default voltage drop and temperature, 14v, 5a, 12ft run, they recommend 14g. Alternatively, 22 g wire has about a 20% voltage drop.

[pontoontodd]

19 hours ago, slammo said:

If you're planning on using a full-pressure fuel pump to deliver to the engine bay, the ABS wiring definitely won't be adequate. Plenty of people say the stock fuel pump wiring isn't adequate lol. But if you're just using a transfer pump to move from aux to main tank, maybe the current draw will be low enough.

 

12 hours ago, el_freddo said:

I’d set it up as an aux Fawcett pump to transfer fuel from the aux tank to the main tank. Far simpler than trying to run a second high pressure pump and work out valves/relays to switch fuel lines to avoid back feeding and sort out the redirection of the returning fuel (unless you run a deadhead setup with zero fuel return). 

This sort of thing is something I want to do with my brumby under the tray behind the cab where there’s a decent cavity. 

 

1 hour ago, Numbchux said:

Personally, I don't think I would trust ABS wires. Small gauge, and twisted pairs. Maybe use all 4 rear ABS sensor wires as positives, and then ground to the body

Using this calculator, default voltage drop and temperature, 14v, 5a, 12ft run, they recommend 14g. Alternatively, 22 g wire has about a 20% voltage drop.

Thanks for all the advice on this.  Good to have someone else looking over my shoulder making sure to at least warn me when I'm doing something I shouldn't.

Yes, we're just using these as transfer pumps.  One for each direction since they all seem to have a check valve built in, the only reversible ones I can find are pretty expensive.

14ga seems overkill for 5A.  I use 16ga for almost everything.  Will take a closer look at the ABS wires for sure, I like the idea of just using them for power and then grounding the other terminal of the pumps.  Will probably see what other wires are running back there we're no longer using too.

 

On the topic of wiring, any suggestions on a relay/fuse good for 80+ amps?  Want to put both the pusher fans on the secondary fan circuit.  Figure I'll switch the big relay I add with the stock wiring/relay.  Those fans pull almost 30A each (over 30A when submerged in water apparently).

Planning on putting both the puller fans on the primary fan circuit, they are small and don't draw as much so I should be good there.  Currently have one of each on each circuit on 30A fuses.