Most performance enthusiasts know that one of the first things you do to increase power from a vehicle is to add an ignition with a hotter spark, such as an MSD. If you really stop and think about this, why isn't just one small spark sufficient? In the cylinder you have a finely atomized mixture of oxygen and highly combustible fuel under compression. Common sense would say that if just one tiny spark occurs, there will be a big explosion and combustion of the air/fuel mixture will occur in the cylinder.

The problem lies in our basic assumptions. Under perfect conditions a single small spark is all that would be necessary for combustion. However, variables occur during each engine cycle that produce less than ideal combustion conditions. For example, large variations occur in the atomization of the fuel molecules. Long manifold runners, chamber turbulence, poorly tuned fuel systems, overly rich mixtures etc. all vary the air/fuel composition in the cylinders and therefore affect the combustion.

Many other factors vary in the combustion process so that perfect combustion conditions rarely exist and the air/fuel molecule composition at the spark plug is never the same from engine cycle to engine cycle. These variations change the time that it takes to burn the cylinder contents on each engine cycle and this is a major cause of lost power, performance and efficiency. The result of these variations is that you can never tune for one condition as the conditions change.

A good analogy of these changing conditions can be made using a common wood 2x4 and a kitchen match. In the first instance, the 2x4 is cut into fine shavings. A single kitchen match can be use to quickly ignite and burn all the wood. This is representative of finely atomized air/fuel molecules in a cylinder being ignited by a single, small spark produced by a stock ignition. Under these favorable conditions the stock ignition worked fine.

Now let's take the same 2x4 and try to ignite it whole using the kitchen match. This is very difficult to do as it takes time for the heat to build and for combustion to start. If we ever do get the 2x4 to burn, it will take much longer than burning the 2x4 cut into shavings. This is the difference between having lots of finely atomized droplets in a cylinder and having a few large droplets that are difficult to ignite. Since the composition of these droplets vary from one engine cycle to the next, the rate of burning also varies between engine cycles. These variations affect power, performance and fuel economy.

How do you overcome these variances in burn times? To answer this, lets go back to our 2x4 analogy. This time, lets's change the kitchen match to powerful flame thrower. If you ignite the solid 2x4 with the flame thrower, the wood is going to burn and be consumed just as fast as if you ignited the 2x4 shavings with a flame thrower. The superior ignition of the flame thrower provides instantaneous and complete combustion of the wood, no matter what the composition of the molecules. There are no variances in the burning times of the 2x4s as there is no smoldering or heat build-up time. The wood is ignited and burned at the same rate no matter what form it was in.

In the real world, this how an MSD Ignition works. At low rpm the MSD produces a series of sparks during each firing instead of one like a conventional ignition. At low engine speeds when the air/fuel molecules are not finely atomized, the multiple spark feature still ignites the mixture. But this isn't the only feature. The number of sparks produced by the MSD Is reduced as engine rpm increases simply because "time" becomes too short to repeat a spark. However, the spark series always lasts for 20 degrees of crankshaft rotation no matter what the rpm and no matter whether it is a single spark or a series of four or five spark. This 20 degree duration spark sequence insures that the air/fuel mixture is ignited and completely burned. Also each spark the MSD produces is an extremely high current spark. Current is like the heat of the flamethrower. Current is what actually does the work or in this case ignites the fuel mixture. Together, the multiple sparks, the high current and the 20 degree duration, produce an ignition that is superior to any other ignition. More importantly though, the MSD Ignition ignites the fuel mixture in the cylinder instantly and insure complete combustion, no matter what the molecular composition is. The result is reduced variations in burn times and therefore more engine power, better throttle response, easier starting and better fuel economy.