Ed,

 

I wish you would test 4 of these. :) If Lynn is correct about high power spark then these might be the ultimate solution. Looks like 3 time the energy of our standard LS1 coils.

 

http://www.msdignition.com/coil_blaster_19_8245.htm

 

Bobby

If Lynn is correct????

 

I am cut to the core young man.

 

I would leave these alone until Tracy gives them the OK for use with his system. To get three times the output you must have three times the input. And switching SCRs come in many sizes and capacities.

 

The primary benefit of the capacitor discharge system is the short rise time. The Kettering system closes a circuit (with the points) to charge up a high turns ratio transformer (the coil)

 

And at the correct time the points are opened so as to  collapse the field in the coil and by means of the step up function of the coil produce a high voltage pulse to light the plug.

 

Inductive reactance, is not a form of critical thinking.

 

When you apply a current to a coil, a flux field starts to form. As that flux field expands through the coil it cuts through the windings you are supplying the current to and produces a current flow in opposition to the charging current. As though the coil didn't like to be charged and is trying to stop you from doing it.

 

This results in a kind of time shift, where the current flow in opposition is called reverse EMF, Just means ElectroMotiveForce, or volts. It looks like a resister of increasing value is being added to the charging circuit. So the coil charges more slowly than we would like.

 

And worse, it never charges fully. There is a 62% rule here and that just accounts for the coils reluctance to be fully charged. You calculate the time it takes the coil to charge to 62% of it full capacity and write that down. It is one time period. So, in one time period we get to 62% of capacity. In the second time period the coil will charge to 62% of what is left, or 62% of the remaining 38% of capacity will charge in the second period, an soon.

 

So, coils don't like to be charged up. Coils never charge to full capacity, ever.

 

When a partially charged coil has its current supply cut off, that big flux field collapses, and as the flux lines cut through the windings, the same thing happens again. A current in opposition the current we want to use is generated, and coil performance is never up to what we want to have.

 

So, all ignition coils are built with much more capacity than you would think required just to account for this feature. 

 

One method of overcoming a high resistance is by increasing voltage. The plug gap is a very high resistance and we keep adding voltage until current flows across that resistance.

 

So if you have two paths for current flow, and one of them is this big air gap on the spark plug, and a parallel path of little balls of lead salts lined up on the center electrode porcelain,

what happens?  Most of the current follows the lead salts to ground, and any excess voltage

is not enough to jump the air gap.

 

But wait there's more.  

 

The resistance in that air gap is variable. It goes up with higher cylinder pressure, and down with lower cylinder pressure. So, when you feel that stumble or "SAG" let off of the throttle a bit and the cylinder pressure goes down a bit and the engine runs fine again.

 

Capacitor systems use electronic trickery to produce a square wave DC that will work in a transformer. That transformer steps your 12 volts up to 400 volts, and pumps 400 volts of DC into a big capacitor. When you need to fire a plug, a very large capacity SCR clamps that capacitor to the coil primary. Designed for 12 volts, the primary looks like a short circuit

to the capacitor. It discharges, very quickly.

 

The same rules still apply about 62% but now that first time period is real short, and 62% of 400 is still a whopping big surprise to the 12 volt coil, and the building flux field is so quick that secondary output exceeds the voltage required to jump the air gap and flow along the lead salts, and arc out of the back end of the spark plug boot to your Twistoflex watch band, and lay you out on the hanger floor.................All on the way up to peak current flow through

the coil primary. So, the rise time (time to reach firing voltage) is so short that the alterative paths like the trail of lead salts or any other paths, (like your hand for example) cannot drain off enough of the voltage to prevent the plug from firing.

 

If you have Stents in your heart, as I do, or a Pacemaker, or a heart monitor/defibrillator, have some young guy work on your ignition system.

 

The MSD (and other) systems use about one amp per thousand RPM. You don't want any part of that kind of energy.

 

Picture is from Western Electric when I still had a mind.

 

Lynn E. Hanover