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· Factory RSP Hardtopper
2015 Ram 2500 Coal Roller
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2,925 Posts
Discussion Starter · #1 ·
Is the 12 volt mod required when doing a full na-tt conversion or does the na pump run at 12v constant? I just installed my triple pump setup and before i put the rear of the car together I would like to know so i can splice the wires if need be. Thank's, Mike
 

· 2JZ NA-T
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7,624 Posts
its not needed..but it does help to get rid of that little lean spike when the pump switches from 4 to 12 volts. here is the thing though, there is two ways to do the 12volt mod.... one propper way and one quick way... i didnt know about the proper way of doing it when i did mine, so for mine all we did was just splice the wires behind the left panel in the hatch, but the right way requires you to put in relays and all that happy stuff so that your pump shuts off when its supposed to, my pump comes on whenever the ignition comes on
 

· Factory RSP Hardtopper
2015 Ram 2500 Coal Roller
Joined
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2,925 Posts
Discussion Starter · #3 ·
I'm rewiring almost the entire fuel system anyway. I used all factory wires from a damaged harness to make it look stock but have 3 wires for power through the stock plug and the sending unit and everything will still work. I just wasn't sure if na cars have multiple pump voltages or not. I have a -10 feed and -6 return so even running constant I'll have enough line to flow back to the tank. Thank's for the help Raven.
 

· Speed limits = Guidelines
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2,352 Posts
from what ive heard, one of the main reasons for the mod is that most aftermarket pumps like walbro require a constant 12v not variable voltage...i did the mod not for that reason, but to try and get rid of the notorious lean spot...didnt help at all

the way i have mine set up, it runs all the time when the key is on, then when turned off it will run for about 10 seconds and shut off...i also have a switch on my dash that shuts down the efi main relay which imediately kills the pump, among a few other things... i use it for security and its also a nice saftey feature, u never kno when u might have to kill the fuel quickly on a heavily modified car
 

· Factory RSP Hardtopper
2015 Ram 2500 Coal Roller
Joined
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2,925 Posts
Discussion Starter · #5 ·
I like the idea of having a kill switch. I think I'm going to use that from you. Thank's for the idea.:)
 

· Speed limits = Guidelines
Joined
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2,352 Posts
there is one downfall to doing it exactly as i have it though, consider this before doing it....im cutting off the efi main relay, which also cuts off the ecu, so if u want to make any tuning adjustments with the car off, ull have to have the pump run the whole time...it gets annoying, the only way around it is to use a high amp switch and cut the pump off directly or wire in a relay, neither of which is somethin i wanted to bother with

but other than that its nice having a kill switch, flip while the cars running and it dies instantly...add that to my relocated clutch switch...id hate to be the thief that trys to get my car started
 

· Factory RSP Hardtopper
2015 Ram 2500 Coal Roller
Joined
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2,925 Posts
Discussion Starter · #7 ·
I think I am going to put an inline switch hidden that will kill power to the relays for an easy bypass.
 

· BoostAddict4Life
Joined
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1,900 Posts
most people run a much larger wire to the back of the car for those fuel pumps. i ran 2 i believe was -8 wires and 30 amp fuses for my two fuel pumps. then you use a relay from the stock fuel pump harness to trigger the pumps to turn on or not. the pump completely have their own power and ground, much more reliable for the ammount of current youl run.
 

· Factory RSP Hardtopper
2015 Ram 2500 Coal Roller
Joined
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2,925 Posts
Discussion Starter · #9 ·
I had to relocate my battery to the rear anyway so the lead from batt to pumps/relays is less that 18".
 
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