phrequenc

iTrader: (3)

Does anyone have the wiring for two relays directly to battery?

I have Hobbs switch with kit but I wanna hardware both pumps.

phrequenc

iTrader: (3)

i drew this up. is there a better way?

michaelrc51

iTrader: (37)

That is pretty much what I am going to do except I am going to use the high/low voltage to turn on the second pump.
Real similar wiring, just you the high voltage circuit to trigger pump 2 and configure it in the ecu.




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211Ratsbud

iTrader: (1)

Would it be wrong to power both pumps at idle but at low voltage ? Parallel wire the oe set up? But use mrfreds rewire plans?

Thinking so that the pump being added doesn't go from one at low voltage, to two at full.

michaelrc51

iTrader: (37)

Guess you could do that,. The way I am going to do it the first pump will be on all the time and the second will come on when the high voltage circuit is activated. I am just going to use the factory wiring as the triggers for each pump. The first pump will be at full tilt all the time.




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phrequenc

iTrader: (3)

well i want to run +14v directly from the battery, which is why im using only the low voltage TURN ON, so technically, the pump is running full voltage all the time.

what i dont understand is that, why would i run 8GA power wire from battery, then step it down to 14ga to run to relay and pump, doesnt add up to me.

how are you guys spliting the power or cables?

michaelrc51

iTrader: (37)

Why would you step it down? Run the 8 guage positive wire through the relay and use the factory power to change state on the relay so when powered you get a closure and positive power through the relay. Wire the 8 guage to the pump and also for the ground. Make sure you use fuses.
I am going to do he same for the high voltage side to run the other pump.



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yellow303EVO

iTrader: (4)

I would suggest using the factory relay and harness for your primary pump, and run the secondary pump parallel with the pressure switch and relay right off the battery.

phrequenc

iTrader: (3)

and why exactly?

211Ratsbud

iTrader: (1)

That's typically how I see them discussed.

michaelrc51

iTrader: (37)

Don't know how they are "typically" done but if I were doing it to my own car I would definitely want it rewired with larger wire, both pumps.
I am guessing here but I would think most people do that since the pump flows fine for idle, even at 12 volts. Then when the other pump kicks on via the hobbs switch it will provide plenty of fuel, especially since the second pump could see up to 40 amps.
My double pumper setup came complete with the wiring harness so I am just going to do the power leeds with the wire supplied and use relays that are driven by the factory high/low circuit.

phrequenc

iTrader: (3)

Where did you buy yours? Do you have a photo? Mine is used and it has a wire coming off it with a Hobbs switch already wired. He said hook it to battery and vacuum line and voila.

I figured the best way to wire it would be direct to battery with two relays and 8ga wire. Both pumps on at all times.

michaelrc51

iTrader: (37)

Here is a quick schematic of what mine will look like. To simplify it I am just using the stock high/low voltage leeds to activate the pumps and then I can use Evoscan to regulate when the second pump comes on. This is just the positive side of the pumps and what I plan to do shortly.

Please note, the terminals are do not correspond to their position on the relay, if you are going to use this as a reference please make sure you go off of the numbers. Also, it should be 85 as the negative and 86 as the positive or trigger, reversed from what I have listed.



If you are just using the stock wiring for pump 1 and a Hobbs switch for pump 2 I think this is how you would wire pump 2. The wires going to terminals 86 and 85 don't need to be any more than 12 guage or make it comparable to whatever amperage you are going to use. Make sure you use sufficient wire, relays, and fuse/breakers for the feed going to/from 30 and 87. Also, this is just switching the positive side so make sure you round the pump with the appropriate cable.