Ferrari Mailing List: Re: electric problem (Non Ferrari question)

[Todd Walke (racertod]

James wrote:
> I am installing water injection on my Porsche 911 which has been
> supercharged.  I am doing it my self and need some help.  I have a
> water pump, solenoid and hobbs switch.  I am using a four pole
> relay.  I have connected the positive side of the pump and solenoid
> to pole #87 and the negative side to pole #85.  Poles #86 and #30 are
> both connected to the battery.  Where do I place the hobbs pressure
> switch so that when I reach a certain boost, everything comes on?  I
> can get the pump and solenoid to work when I apply positive current
> to #30 and #86 but it seems that no matter where I place the hobbs
> switch, either nothing works or it works without the hobbs switch
> applying the vacum when the boost comes on.  I don't want it running
> all the time, just when I reach a certain boost (4 lbs).  Thanks.

        Terminals 85 & 86 trigger the coil.  Terminals 30 & 87 are not 
connected electrically until the coil is triggered.  To put it another way, 
when a voltage is applied through 85 & 86, terminal 30 gets connected to 
terminal 87.  Common practise is to connect terminal 30 to power and 87 to 
the load.

        So, battery power to terminal 30.  Terminal 87 goes to positive 
side of pump.  Negarive side of pump to ground.  Terminal 86 to 
ground.  Terminal 85 to one terminal of the Hobbs switch.  Other terminal 
of Hobbs switch goes to the battery.
        When the Hobbs switch closes, it will complete the 85/86 
circuit.  The coil will close and connect the pump to power.

        What, hard to visualize?  You'd like a diagram?  Done...


Todd
Seattle,WA
'86 GTI, Red of course. (exciting racey car)  268,000 miles
'87 Golf, Polar Silver. (boring work car)     641,000 miles <- Yeah, baby!
http://www.pureluckdesign.com <-Ferrari & VW stuff

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