Re: [DML] High Voltage Coils, High Octane Fuel

[Paul Gress <pgress@xxxx>]

On 12 Nov 2003 12:14:38 -0000, <dmcnews@xxxxxxxxxxxxxxx> wrote:

I've been reading this section now for a while. There are a couple of 
points I need to make. The voltage of the ignition is regulated by the 
"spark gap". This happens to be the spark plug. The voltage will only 
build up until a spark can avalanche across the spark plug electrodes. 
It usually requires the most voltage at times of peak compression, which 
is during full throttle. To take advantage of being capable of 
generating greater voltage, you have to widen the spark gap. If you 
don't do that all your really buying is longer lasting spark plugs. The 
next topic is the ignition coil. When you apply a voltage across its 
primary coil, the voltage on the output begins to build up. As the 
voltage is building up, the current being drawn by the primary coil is 
inductive, and the ferrite (magnetic) core is still charging greater. 
Once the current or voltage has been there for a short period of time, 
the ferrite core will be fully magnetized. After this point, the 
current draw will not be inductive, but will turn to resistive. This is 
the saturation point. Now the coil will start increasing the amount of 
current its drawing, because at approximately 1 ohm, its almost a short 
circuit. This is the reason for the ballast resistor, to limit current 
so you don't burn up the primary coil windings. Usually ignition coils 
with different magnetic cores tuned for higher frequencies (RPM's) will 
saturate at a higher rpm and may require greater resistance (ballast 
resistors) to prevent overheating or burning up the primary circuit at 
lower rpm's.

Paul Gress
vin 10193
> Date: Tue, 11 Nov 2003 04:47:05 -0000
> From: "David Teitelbaum" <jtrealty@xxxx>
> Subject: Re: High Voltage Coils, High Octane Fuel
>
> Getting technical now there is a property called "saturation". Simply
> stated you can only put so much energy into a coil, any more and it
> won't give you anymore output. Using a coil with a higher ratio of
> turns in it may give you more output voltage but only up to the
> saturation point. That point is reached as the RPM's increase. 

[moderator snip}