Wiring Up Fuel Pumps, Battery In The Boot In A 32

[boostn32]

Hi im currently trying to wire up my fuel pumps, i have a 500hp walbro in tank and a bosch 044 external after surge tank.

how many amps would these pumps draw combined? would it be safe to run both out of a 30A relay that has two power out terminals?

im using the factory fuel pump wire as signal wire, that has a fuse on it. do i need any other fuses?

im assuming the intank would draw bugger all amps as its not required for pressure just flow to fill the surge tank, also the 044 is mounted under the car

so will get cool air flowing over it keeping it cool?

when puting the battery in the boot of a 32, do you need to run a earth cable to the front or just a good ground in the boot?

where do you run the power cable to in the engine bay and hook up up the factory stuff?

Thanks Luke

Edited August 1, 2010 by boostn32

[t_revz]

battery can be earthed to good clean chassis bolt in the boot. hook positive to good size connection such as starter motor or if the fuse panel has large positive like the 33`s it could go there. fairly sure 044 uses 12-15 amps and walbro 6-10.

[kyle785]

as above but make sure you use i reply per fuel pump and i fuse per pump

[boostn32]

so i cant use the 30A relay for both, should i put a fuse to each pump from the relay, what amp fuses?

[Kinks]

how many amps would these pumps draw combined? would it be safe to run both out of a 30A relay that has two power out terminals?

im using the factory fuel pump wire as signal wire, that has a fuse on it. do i need any other fuses?

yes you must fuse any wire that comes from a power source (battery/alternator/etc). so your wiring will consist of the factory fuel pump "signal" wire which is triggering the relay coil, this is fused already. You need to run a power wire from the battery (which should be fused as close to the battery as possible) to the relay and then from the relay to the fuel pump(s).

The idea behind fusing is it protects the wiring/devices downstream, so your fuse must be smaller than the current capacity of your wires. Eg if you run 25 amp auto cable then your fuse must be 25 amps or smaller. Any time you step down in wire size you need to put another fuse in with the current capacity of the new wire size.

I would not bother with separate fuses to be honest - I would run a fused line from the battery back to your relay, then have that powering both pumps. If one of the pumps faults and blows the fuse then having the other one running is not going to help you anyway. Not like you can limp home with one pump running.

[boostn32]

fairly sure 044 uses 12-15 amps and walbro 6-10.

so i can run both pumps off 1 30A relay?

[mattis96]

can you splice the trigger wire to run multiple relays since the main power is coming from somewhere else?

[jangles]

wouldnt need to splice it, just loop at the relay.

the point of a relay is low current switching