Fuel pumps and hobbs switch??????
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Fuel pumps and hobbs switch?????? First off I hate electrical junk... Let me ask the probably stupid question...
People who run a hobbs switch for there secondary fuel pumps why is a relay used?
Just curious why would you not just run a direct feed from alternator to hobbs switch and then to the fuel pump and add an inline fuse? The pump would not get power till the hobbs switch activated.. Just dont understand the relay in this case...
(edit)Here is the hobbs switch that I run... Doesnt give an amp number but it looks pretty stout..
http://napaautoparts.com/Search/Resu...word&Nty=1&N=0
People who run a hobbs switch for there secondary fuel pumps why is a relay used?
Just curious why would you not just run a direct feed from alternator to hobbs switch and then to the fuel pump and add an inline fuse? The pump would not get power till the hobbs switch activated.. Just dont understand the relay in this case...
(edit)Here is the hobbs switch that I run... Doesnt give an amp number but it looks pretty stout..
http://napaautoparts.com/Search/Resu...word&Nty=1&N=0
Last edited by mikep2002; Jan 22, 2011 at 02:36 PM.
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I am not quite getting it.. The relay is hooked to a trigger wire off the ignition. So if the car is running is there power to the hobbs switch hot side?
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Pockets, thanks looking at the schematic.. It looks as if the hobbs switch is being used to complete the ground and activate the relay? And you also mention it can go from the power or the ground. If you would use the power side as you mention what is the purpose of the relay?
Like I was saying if you use the power side of the relay on the hobbs (meaning there is power on one side of the hobs switch) what is the purpose of the relay? When I look at this diagram in this thread appears to be on the hot side... https://ls1tech.com/forums/fueling-i...g-diagram.html
Like I was saying if you use the power side of the relay on the hobbs (meaning there is power on one side of the hobs switch) what is the purpose of the relay? When I look at this diagram in this thread appears to be on the hot side... https://ls1tech.com/forums/fueling-i...g-diagram.html
relays are basically designed to use a low amp wire(small in size 18g-22g) to activate a circuit using higher amp wire(8g-12g). So there wouldnt be a need to run 8g to your hobbs switch and then back to the pump. All factory cars are designed with relays for this reason. Hope that makes a little better sense.
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Mike, please don't take this the wrong way, it seems you don't understand the purpose of using relays in an electrical system. It's not as easy as connecting power to a wire or switch to turn on a device. In simple terms, a relay is similar to putting a dam in a river, it stops the heavy flow yet allows enough thru to do the job. Here is a great reference for using relays. I hope it helps.
(Another) Mike
(Another) Mike
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Here is the most lay mans way I can be put. A relay allows you to power heavy amped components without the need to run heavy amps threw your switch.
They due this for several reasons. One you dont need heavy wires to run up to you dash switches. (allowing for smaller switches,alot less wire, or weight)
Lower amp switches are cheaper, lighter. so weather its a head light switch, interior dimmer or a hobbs switch you dont need to run 15 amps threw it. Also makes them last longer in my experience. Hope this help. The question I have is im running a bypass regulator ( obviously return style system). Why do guys run the second pump on a hobbs switch? why not just let it go back to the tank. Sorry for the hi-jack.
They due this for several reasons. One you dont need heavy wires to run up to you dash switches. (allowing for smaller switches,alot less wire, or weight)
Lower amp switches are cheaper, lighter. so weather its a head light switch, interior dimmer or a hobbs switch you dont need to run 15 amps threw it. Also makes them last longer in my experience. Hope this help. The question I have is im running a bypass regulator ( obviously return style system). Why do guys run the second pump on a hobbs switch? why not just let it go back to the tank. Sorry for the hi-jack.
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From: Oxford, Chester County,Pa
Here is the most lay mans way I can be put. A relay allows you to power heavy amped components without the need to run heavy amps threw your switch.
They due this for several reasons. One you dont need heavy wires to run up to you dash switches. (allowing for smaller switches,alot less wire, or weight)
Lower amp switches are cheaper, lighter. so weather its a head light switch, interior dimmer or a hobbs switch you dont need to run 15 amps threw it. Also makes them last longer in my experience. Hope this help. The question I have is im running a bypass regulator ( obviously return style system). Why do guys run the second pump on a hobbs switch? why not just let it go back to the tank. Sorry for the hi-jack.
They due this for several reasons. One you dont need heavy wires to run up to you dash switches. (allowing for smaller switches,alot less wire, or weight)
Lower amp switches are cheaper, lighter. so weather its a head light switch, interior dimmer or a hobbs switch you dont need to run 15 amps threw it. Also makes them last longer in my experience. Hope this help. The question I have is im running a bypass regulator ( obviously return style system). Why do guys run the second pump on a hobbs switch? why not just let it go back to the tank. Sorry for the hi-jack.
Last edited by mikep2002; Jan 24, 2011 at 06:03 PM.
