im planning on runnning an intank 255 walbro along with a inline 255 walbro and was wondering if i can just use one relay and splice the power and ground wires to the fuel pumps. or would it just be a better idea to run them seperate and wire each individually from the battery?

 

you can but I would not do that, 2 relay is right way

 

I used a big 75amp relay I found on ebay. It's a bosch/tyco 75amp, costs about $25/shipped. It has screw terminals which I liked as well, and it's not some shitty parts store 20amp relay that will fail and leave you stranded on the side of the road.

I fed it 8gauge from the battery, then 10gauge to each pump with fuses on each 12v. Ground/Trigger for the relay is 12gauge. Ground from the pumps is 10gauge.

This is feeding a Walbro 255hp pump in tank, and a Bosch 044 inline. I run them both at the same time for simplicity sakes.

This is in a DSM.

 

I would come off the main relay to 2 bosch 40amp relays. That way they get more power to the pumps.

 

http://autoperformanceengineer....html

Each pump won't pull more than 17 amps with full pressure load.

Also, since your intank (first pump in series) is feeding the second pump, it will not create much pressure like the second pump which has a fpr on it, thus not requiring much current to drive it. If I had to guess, you'll be using less than 15 amps combined between the 2 pumps. A single 40 amp or greater relay of decent quality will easily suffice.

Now if you were running the pumps in parallel, they would each see load and drive current up near 18-30 amps...but unless your putting down 800hp+ why would you need two pumps in parallel

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tricura &raquo;</TD></TR><TR><TD CLASS="quote">I would come off the main relay to 2 bosch 40amp relays. That way they get more power to the pumps.</TD></TR></TABLE>

How I ran my Dual Walbro's. I have a rear mounted battery so I ran indepentent 10ga's off the battery to inline fuses to each relay.

 

here ya go

 

just so you know, full blown makes dual intake fuel pumps for hondas

https://honda-tech.com/zerothread?id=2138241

id rather do that than mess with inline pumps

 

i have less into my pumps and an fittings and lines than what it costs to buy the fullblown setup......

thanks for all the diagrams and whatnot though

 

Keep things simple and run one 12 VDC 30-40 amp relay to power both pumps using a parallel circuit. It will not make a difference in your case since the total current(amp) draw from both pumps will stay under 18-26 amps. Using this method voltage and amperage will be supplied to the pumps the same way as they would with the extra relay minus unecessary relay/wiring and less time spent for future diagnostics.

 

40 amp relays are hard to find and not needed one 30amp should work just fine.
What I recommend is 2 relays but tie them back together and run them to both pumps. That way if one relay fails the other one will still allow power to pass through it. Every race car I have ever setup I have done this way. I use diodes and LED's to show if a relay dies.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by White Smoke &raquo;</TD></TR><TR><TD CLASS="quote">40 amp relays are hard to find and not needed one 30amp should work just fine.
What I recommend is 2 relays but tie them back together and run them to both pumps. That way if one relay fails the other one will still allow power to pass through it. Every race car I have ever setup I have done this way. I use diodes and LED's to show if a relay dies.</TD></TR></TABLE>

smart idea

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by White Smoke &raquo;</TD></TR><TR><TD CLASS="quote">40 amp relays are hard to find and not needed one 30amp should work just fine.
What I recommend is 2 relays but tie them back together and run them to both pumps. That way if one relay fails the other one will still allow power to pass through it. Every race car I have ever setup I have done this way. I use diodes and LED's to show if a relay dies.</TD></TR></TABLE>diagram for the lazy please

 

summit has relay kit would it work? it has 30 amp relay and harness??

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ctr83 &raquo;</TD></TR><TR><TD CLASS="quote">summit has relay kit would it work? it has 30 amp relay and harness??</TD></TR></TABLE>

yes it would work. you would just have to add more wire for the second pump

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by gsrious &raquo;</TD></TR><TR><TD CLASS="quote">diagram for the lazy please </TD></TR></TABLE>

look at the diagram i posted an loop the power wires together. the diodes and LED's could be wired off of the blue wire that goes to the factory power wire if you decide to use that diagram

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tony413 &raquo;</TD></TR><TR><TD CLASS="quote">

loop the power wires together. </TD></TR></TABLE>

explain further plz

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 96 GSR-T &raquo;</TD></TR><TR><TD CLASS="quote">

explain further plz </TD></TR></TABLE>
in the diagram from earlier

the Relay is as follows from LEFT to RIGHT

far left = 86 ( ground )
top = 87 = constant 12v battery
middle = 87a = nothing
far right = 86 = 12v ignition from the factory harness line
bottom = 30 = power to fuel pump from relay

what you want to do to find out if a relay goes out is wire a diode inbetween (86) and the factory line. if the relay loses power for any reason the LED is not going to light up.

as far as wiring to relays together to use as a joint unit you could loop the two 87 wires together and run them to the alternator. as they are for a constant 12v signal, if one pump goes out the other will still work if it hasnt blown

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tony413 &raquo;</TD></TR><TR><TD CLASS="quote">here ya go
</TD></TR></TABLE>
do you ground the fuel pump and relay to the body or battery?

 

I grounded mine to body.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ctr83 &raquo;</TD></TR><TR><TD CLASS="quote">
do you ground the fuel pump and relay to the body or battery?</TD></TR></TABLE>

you ground the 86 wire to the body remember that the factory harness is still grounded to the battery.