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

[coyote (coyote]

   James -



   First of all read this ...



   [1]http://www.partsexpress.com/resources/automotive-relays.cfm



   Ok, this what you need to do.



   Terminal 30 on the relay goes directly to the battery through a fuse
   of the proper size.



   Terminal 87 on the relay goes to the + side of the solenoid and pump.



   The (-) side of the solenoid and pump goes to ground.



   I'm not familair with a 'hobbs' switch, but I'm guessing it is an
   on/off switch controlled by boost with two pins.



   One side of the switch will go to ground, the other will go to
   terminal 85 on the relay.



   Terminal 86 on the relay will go to a switched (with the ignition)
   source of + 12v.



   This way, when the hobbs switch closes, it will in turn complete the
   circuit to the coil in the relay, which in turn will energize the
   pump.



   Think of the relay as another switch. Its purpose to switch a heavy
   load (in this case your solenoid and pump) via another switch (your
   hobbs switch) which can't directly handle a heavy load.



   Also, be sure to use a heavy enough wire on the load side of the
   relay. The wires to and from the hobbs switch can be much lighter.



   Lastly, a correction in your terminlology is in order. The most common
   relay an probably what you are using is actually an SPDT relay, which
   stands for Single Pole, Double Throw. A four pole relay would actually
   have four seperate switches internally, controlled by the same switch
   signal. It is double throw since there are two internal contacts on
   the load side, usually 87 and 87a, one normally open (relay at rest)
   and one normally closed (relay at rest) whose state(s) change when the
   coil is energized.



   LMK if you have any questions.



   Sorry for the interuption in the now normal Guns/Global
   Warming/Sticker Gate/Watch/Cats what have you debates ... yes I've
   been around here that long ...



   Jeff



   ------- Original Message --------
   Subject: [Ferrari] electric problem (Non Ferrari question)
   From: "James V. Cunningham" <vikelj [at] comcast.net>
   Date: Wed, January 16, 2008 9:11 pm
   To: Jeff Greenfield <COYOTE [at] acme-ltd.com>
   Cc: The FerrariList <ferrari [at] ferrarilist.com>
   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.
   Jim
   James V. Cunningham, Esq.
   410-625-7400
   [2]http://home.comcast.net/~vikelj/page3.html
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References

   1. http://www.partsexpress.com/resources/automotive-relays.cfm
   2. http://home.comcast.net/~vikelj/page3.html
   3. http://lists.ferrarilist.com/mailman/options/ferrari/coyote%40acme-ltd.com
   4. http://www.bidnip.com/
   5. http://www.f1headlines.com/