got a 12vdc relay for the rotaryresurrection.com electric 6th port act. setup. And i am confused by how to wire the relay. The diagram is below. I am using the MSD RPM switch and a 12v air compressor pump. How should i wire this so that at 4000 rpms or whatever pill i use, the air pump turns on? and of course, below 4000 turns or stays off?

 

i am stupid, here is the diagram

 

I've never read Kevin's writeup on this, but I can't believe he didn't say how to wire the relay up. You basically have two circuits to worry about- the coil circuit, which is nothing more than power (12vdc) and ground, and the contacts circuit, which will be the "switch" that sends power to the air pump. In the picture, 85 and 86 will be the coil circuit (needs a power on one and ground on other), 30 will be another power wire (could be a splice from 85's power wire, or could be from an entirely different circuit), and 87/87a will be the wire(s) to the air pump. Other variations are possible, depending on circuit design...

 

the 12v comp has a neg and pos, then the MSD has two wires put that goes in line. i need power off the batt. (+) to 85 then i could ground 86 to the chassis of the car. Then the power to 30 could be from the batt (+) too. (?) Then the 87 would go to the 12v pump?

1) so where does the ground from the 12v pump go?
2) the MSD switch does where in this mess?

 

The rpm switch should go either on the power or ground side wiring of the relay coil circuit, because the way you just described the setup, the relay would be energized all the time, and you obviously don't want that...

Man, you need to get some human help, in person. Know anyone that could help you with this? That's my opinion from reading the types of questions you're asking. Is there a complete electrical diagram in Kevin's writeup?

 

he gives a rather...well here ill cut and paste it from the article.

from the rotary resurrection.com tech article

ON the 89-91 NA, find the white and brown solenoid plugs, and reuse those stock solenoids. These plugs are the ecu signal to actuate the ports, and will both open the vacuum solenoids and trigger the motor to turn on. ON older models, your custom rpm trigger will be used in place of them, but you’ll still need a solenoid. To wire up the relay, s5 owners will use both wires from the brown solenoid for a trigger…I use coax speaker wire for this. IF setting up an older car, your trigger wires will come from the rpm trigger, and you’ll also need to run these wires to your solenoid as well. Don’t try to pull power for the motor directly from these triggers, they are not meant to carry amperage…this is why the relay is used.

Run these trigger wires to the fender well area where the relay will be mounted. Use the 2 right hand terminals for trigger (unless your relay diagram shows differently).
Ground the motor to the chassis…
Run the power input to the motor, to the relay…either terminal is fine.
Then, pull battery power from either the main fusebox, or the battery terminal, and run it (a fused wire is necessary here) to the remaining relay terminal. Now, run the hose from the motor to the solenoid(s). For 89-91’s, you’ll split this hose, using a tee, into both the 6 port (brown) and vdi (white) solenoids. For older models, the hose can go directly into the solenoid you’re using. The input of these solenoids is the top port..the lower ports are output and vent to atmosphere and are connected when the solenoid is off.



Okay i am getting confused between the 89 years and my 87. Also how it is said, "connect to relay" i dont know what part of the relay.