Here's what you'll need:
1- leading coil from a 2nd. Generation RX-7 (86-91)
1- 14-16 gauge wire connector
1- male spade connector
1- female spade connector
Tools:
wire stripper/crimper (about $5 at an auto parts or hardware store)
phillips head screwdriver
8mm wrench or just a pliers
Before you get started know this, I take no responsibility for anything you do to yourself or your car or anyone/thing else while attempting this mod. So dont come complaining to me if you don't disconnect the battery and you fry the shit out of yourself.
Part 1: Rewiring the coil
You'll want to cut off the connectors for the stock wiring now.
So now you're going to need to take off the four screws from the back of the coil. One of mine was rusted badly so I had to drill it out but otherwise there should be no problems.
The inside should look something like this...
There are two types of coils out there, one (as pictured above) has the resistor (little white rectangle) wired in with the tan wires, while the other kind has it wired in with the black wires that are on the left. I'll cover both (theres really no difference)
(Warning!) Before you do this next step you should know that there is a newer version of this modification that requires that you keep the ignitor, and purchase a circuit board to utilize it. It's called the transistor trick and will give you an even stronger spark than the modification described here. If you don't need THAT strong of a spark and/or are cheap like me, read on.
Now take the wire cutter and cut off all the wires as close to the ignitor as you can. The ignitor is the gray thing in the middle...
Now you're going to want to connect the tan wires (or black if you have the other kind of coil) that were soldered together on the ignitor using your 14-16 gauge connector. Crimp the connector on both ends.
Now it should look something like this...
The tan (or black) wires are all your are going to need to keep, so go ahead and pull out the rest.
If you have the coil like me where the resistor is wired through the tan wires to the positive side of the coil, then it may be easier for you to just switch it to the negative side. All you have to do is move the ring terminal attached to the end of the tan wire from the positive pole to the negative pole.
Check it out!
Take the other wire that just sticks out the top of the coil and crimp the male spade connector to the end of it.
You've completed Stage 1! Celebrate!
Now it should look something like this.
Stage 2: Under the hood
DISCONNECT THE BATTERY! Just pull off the negative terminal. The first thing you'll need to do is to locate your leading ignition coil (driver's side, its the one closer to the rear). Pull off the wire going to the distributor, you wont need it anymore (I keep mine in the car in case my new coil fails I can set it up to use the old one on the side of the road).
There are two terminals on the coil, disconnect the wires going to both.
The line running to the positive terminal should have a ring connector on it. If you wired the resistor in line with the negative side of your coil (as I suggested earlier) then you can just leave that ring connector alone, as it will go straight to the postive terminal on the new coil.
The line running to the negative terminal had a sort of female spade connector on mine, though I'm not sure if this is normal. If yours also has one you can just as well leave it alone. In my case I was experimenting with different set ups and cut it off. I then stripped the wire and crimped it into a new female connector.
Now you can mount the coil (you could have before this last part too, the order of some of the steps is not absolute)
There are many ways to mount the coil, most of them locate it on the driver's side strut housing. Through experimenting I found a very simple way to mount it which involved no drilling or even new screws or bolts at all.
On the driver's strut housing of my car there was a little black box with a bunch of wires running to it (no fancy terminology here ;)) It was designed to be held there by two screws (mine was missing one...). I unscrewed it and simply moved it out of the way, over by the stock coils. It holds itself there, theres really no need to screw it down. I then took one of the left over screws and used screwed it through one of the bolt-holes on the 2nd gen coil.
Here's a picture to see where it's directed. I pointed it forwards only because that way the wires from the old coil could reach the terminals.
And yes I know, my engine bay is dirty. I'm getting around to it.
The screw goes in the bottom left side hold on the coil (if you're looking down like in the picture)
Now obviously just one screw is not going to hold it very well so I just used some picture wire and threaded it as you can see in the picture. Works great so far, and hey, its shiny if you're into under-hood bling ;)
Picture wire and old wires run to new coil.
The next step is now to attach your ring connector from the positive wire to the positive terminal, and connect the two spade connectors for the negative line.
Finally pull the line coming from the stock trailing coil (the other one...) off the distributor, and move it to the spot formerly occupied by the leading wire. Now pull the lines going from the distributor to the leading plugs off the distributor. Move the lines going to the trailing plugs from the trailing spots on the distributor to the leading spots. and attach them to the new coil.
Now if you're using the stock wires (like me), attaching the leading plug wires to the new coil will be a trick. Supposedly there is a way to move the rubber cups at the end of the line farther back so that they fit, but I simply cut off the cups entirely. This exposes the metal connectors and allows the to slide easily into the new coil. Keep in mind this means the connection is not insulated and could cause problems. If this bothers you, you could always wrap it in electrical tape or use some other rubber thing to insulate it. Your choice.
Also you could scavenge some 2nd. Gen wires out of a junk yark or off the internet. Those lines are also longer so they wouldnt be so stretched. That is probably what I will end up doing, or else splurging on some new aftermarket wires for even less resistance.
Heres how the distributor wiring should look.
Once you have those connected you should be ready to rock. Make sure none of your wires or anything interfere with the engine pulleys or other moving parts. Then reconnect your battery and start her up! She should start better and run smoother than ever before. Plus you get more complete combustion which means better gas mileage and more power. Though you will lose much of your cars backfiring power... Now go out and enjoy it.
P.S. Reset your clock, it will be off now and god forbid you miss work/school/sex/anything-else-you-need-to-be-on-time-for because of me.