The Ultimate Goal of an Ignition System
The ultimate goal of an ignition system is "total ignition" of the air/fuel mixture in the cylinder. Obviously, there is no way to measure gains of "total ignition" except for horsepower increases measured with a dynamometer. It would be impossible for ignition manufacturers to sell a "20 Horsepower" or "50 Horsepower" ignition like camshaft or nitrous manufacturers do. Because of this, varying electronic specifications are used when describing ignitions, resulting in room for exaggerated claims of output voltages of spark energy.
One specification we would like to discuss is the output voltage or secondary voltage of the coil. This is the most referred to and exaggerated technical specifications used to judge ignition systems. Secondary voltage figures become popular to use when talking about ignition systems simply because the numbers were high. Coils and ignitions with claims of 60,000 volts or more are common. Anyone who has ever been shocked by their 110 volt household system has a pretty good appreciation for electricity. Now if they buy this 60,000 volt system they believe they should have 600 times more voltage then when they were shocked at home. SO THEY BELIEVE. The secondary voltage is just one of the things to consider when building an efficient ignition system. Current or amperage is what does the actual work, or caused the pain at home. There must be enough voltage at the spark plug to jump the gap, but after that, the current is what does the actual work to ignite the fuel mixture.
The high secondary voltage quoted by some manufacturers are nothing but a voltage potential that is possible to obtain in laboratory conditions with no load placed on the ignition system. Theoretically, this figure is possible. Realistically, in your engine, forget it. In fact, with most stock ignition systems, the secondary voltage distribution system (cap.rotor, and wires) is only capable of handling about 35,000 volts maximum. Although distribution of over 40,000 volts is possible using a MSD cap-a-dapt that still a far cry from the exotic voltage claims that have been made.
At MSD we use standards set by the Society of Automotive Engineers (SAE) and the California Air Resources Board (CARB) to test our ignitions. High secondary voltage specifications are of no real value when trying to evaluate an ignition system. Things like duration and spark energy are the important factors
The purpose of this article is not to put down other manufacturers ignitions but to make you, the customer, realize that there is more to an ignitions system than just secondary output voltage. MSD encourages you to take into account these other specifications and compare, as we are confident in our products.