Hobbs Switch Yes or No?

[8urV8]

Hey guys almost done with the car,and have the Reds XP 340 DP setup.Is it best to run both pumps full time,or does it cause the second pump to get out weaker faster?The hobbs switch setup best to run with this setup,or not?Just wanted to get input from guys that run this setup.

Thanks
Eric

 

[salvageV6]

I've had the NAPA one on my car for 5 years now with no issues.

It's under the hood near the passenger side relays and downpipe area, very reliable and stays calibrated to your turn on point they make two models and both are adjustable.

I use mine for a second stage alky. nozzle set at 18psi. turns on an approx. 1A solenoid draw not a pump directly.

You could always use the Hobbs switch to trigger a hot wired second pump, turn on fuel pump relay, rated 30A or 40A.

I believe the Hobbs is rated at 15A current itself however which may be enough to run a second pump directly.

 

[pacecarta]

problem with duals and a stock returnline is the pressure with one pump may be 43 psi , the lowest pressure with two on might be 50 or higher , so you would want to have the second one staged with the hobbs to atleast stay off until you're over 7psi boost (10 is norm on most),
most DP ive seen run second pump just powered through the hobbs and no relay. ive never heard of a problem that way but installed a relay in mine anyway


if you have an upgraded return system and with both pumps running and the pressure will drop at idle to the std of 37 or so ( 43-45psi base - vac (15in hg ) which is about a 7-8psi FP drop ) than you could run both all the time. no real harm just means two pumps are wearing out but at same time you don't have to worry about the one that sits not turning on either because of a switching problem or from not using

i run an adjustable hobbs and switch across it , and another switch for my primary pump to allow testing of the both pumps every time i lift the hood ,
still running stock lines so i have the second hobbs set at 12psi so it doesnt come on while Im spooling at the line

 

[MSDGN]

You won't be able to run both pumps with stock fuel lines...mainly the return...can't handle the volume...why run both pumps anyways?...hobbs switch will bring in the second only when needed

 

[cork]

Where is the hobbs switch normally located ? I have a Reds Dual pump setup but never noticed the Hobbs switch.

 

[8urV8]

I forgot to mention that my car has upgraded fuel lines running a -8 supply and a -6 return.So is it okay to run both or no?Will there be some kind of voltage issue?

 

[A2000RICH]

most DP ive seen run second pump just powered through the hobbs and no relay. ive never heard of a problem that way but installed a relay in mine anyway

funny you say this--------i built a car several months ago with reds dual pump setup------car had a FAST-------ran fine for a few weeks------started running funny ie good then bad then good then bad for no reason------put it on the dyno and checked lots of things-----tried correcting fuel tables and nothing made any sense------like we were chasing our tails all over the place-----must have done 20 pulls------then discovered fuel pressure at 28lbs of boost sometimes fell off-----different every run-------finally discovered that the pump switched by the switch sometimes would only get 8 to 9 volts----sometimes 12 or 13------and sometimes anywhere in between------traced it to intermittent drop across the switch-------rewired it so the switch activated a relay and problem gone-----red said the switch rating should have been adequate but i will never do another car without this simple low cost safeguard.............RC

 

[steve hughes]

Run both pumps all the time.

 

[Just a Six??]

Hobbs with a relay turned on at 15 in mine. All with the Racetronix Plug & Play wiring that is a really nice setup!

 

[A2000RICH]

Run both pumps all the time.

he's already explained why you can't with stock fuel lines-------unless the engine is using at least a portion of the gas through the injectors the regulator and stock return line can't get all the unused gas back to the tank and this results in an increase in fuel pressure above the actual set point of the regulator..........RC

 

[TurboDave]

funny you say this--------i built a car several months ago with reds dual pump setup------car had a FAST-------ran fine for a few weeks------started running funny ie good then bad then good then bad for no reason------put it on the dyno and checked lots of things-----tried correcting fuel tables and nothing made any sense------like we were chasing our tails all over the place-----must have done 20 pulls------then discovered fuel pressure at 28lbs of boost sometimes fell off-----different every run-------finally discovered that the pump switched by the switch sometimes would only get 8 to 9 volts----sometimes 12 or 13------and sometimes anywhere in between------traced it to intermittent drop across the switch-------rewired it so the switch activated a relay and problem gone-----red said the switch rating should have been adequate but i will never do another car without this simple low cost safeguard.............RC

Good catch.. I run staged ATR double pumpers, and the hobbs switch for pump 2 controls a relay....actually both pumps are hotwired through hd relays.

I've since pulled the hobbs switch out though in favor of electronic control via the Translator Pro. More precised control and one less mechanical device to worry about.

 

[Sam Colalillo]

he's already explained why you can't with stock fuel lines-------unless the engine is using at least a portion of the gas through the injectors the regulator and stock return line can't get all the unused gas back to the tank and this results in an increase in fuel pressure above the actual set point of the regulator..........RC

Did you not read where he stated he upgraded the fuel lines and is running a -6 return.

I forgot to mention that my car has upgraded fuel lines running a -8 supply and a -6 return.So is it okay to run both or no?Will there be some kind of voltage issue?

Run both pumps all the time.

I agree with Steve, as long as the charging system and the circuits feeding the pump are in good shape you should not have any problem running both pumps all the time.

Steve and I are both pumping more fuel than a set of dual pumps, and we are not having issues. I am running a -6 return line with an Aeromotive 1004 fuel pump which has 14 volts or more going to it all the time.

 

[8urV8]

Thanks for the info guys....My best friend and builder said the same thing...Ill try harder to trust his judgment...Ill run both pumps...

 

[3.8vsix]

Does any one sell a hobbs relay switch if not, does anyone have a diagram of how to hook it up or a pic?? I am fixing to put a double pumper in shortly and this is the first I have ever heard of having to use a relay. I do not understand relays that well, esp like this.

 

[pacecarta]

napa

NAPAONLINE®15psi hobbs switch

my local napa looked at me like i had two heads when i asked for a hobbs switch , had to show them the printout from the online site

hobbs isnt a relay its justa pressure activated switch , used for farm and commercial equipment, installed in the oil pressure system to activate an hourmeter to keep track of run time for servicing

just run from alternator with an inline fuse to one terminal on hobbs from other terminal on hobbs to the pump

and hook a boost line to the hobbs (its 1/8npt male so you'll need an 1/8npt coupler and an 1/8 npt male to hose fitting ( like the one at your turbo compressor cover or to whatever type or size hose you want to run ))
i pull the vac source for the hobbs from the line to the egr and mount the hobbs either at the fender plastic or on a screw of the valve cover with a simple L bracket and some zip ties to the coupler fitting, you could wrap the terminals with tape or better a peice of electrical shrink wrap

if you want to run a relay use the hobbs to switch a relays solenoid

if you dont feel your up to the wiring task contact racetronix.com for his Dbl Pumper harness
his includes everything needed from front of car to the pumps including the means to get the second pumps 12v into the tank safely
http://www.racetronix.com/product/RX-G7-DP-FPWH/G7-DP-FPWH.jpg

 

[3.8vsix]

napa

NAPAONLINE®15psi hobbs switch

my local napa looked at me like i had two heads when i asked for a hobbs switch , had to show them the printout from the online site

hobbs isnt a relay its justa pressure activated switch , used for farm and commercial equipment, installed in the oil pressure system to activate an hourmeter to keep track of run time for servicing

just run from alternator with an inline fuse to one terminal on hobbs from other terminal on hobbs to the pump

and hook a boost line to the hobbs (its 1/8npt male so you'll need an 1/8npt coupler and an 1/8 npt male to hose fitting ( like the one at your turbo compressor cover or to whatever type or size hose you want to run ))
i pull the vac source for the hobbs from the line to the egr and mount the hobbs either at the fender plastic or on a screw of the valve cover with a simple L bracket and some zip ties to the coupler fitting, you could wrap the terminals with tape or better a peice of electrical shrink wrap

if you want to run a relay use the hobbs to switch a relays solenoid

if you dont feel your up to the wiring task contact racetronix.com for his Dbl Pumper harness
his includes everything needed from front of car to the pumps including the means to get the second pumps 12v into the tank safely

Thanks alot that helps!! So this switch is a hobbs and relay combined??

 

[TurboDave]

No, that napa online link is to a hobbs switch only.

 

[salvageV6]

I believe the BK stands for the Balkamp line book, it could be a special order but shouldn't take more than a day or two to get if not in stock.

Most NAPA people don't know they even have a Balkamp book to look stuff up in.

And it's not easy to search at NAPA if you don't know the prefix code or that it's in the Balkamp line to search for it via computer.