Distributorless Ignition Systems (DIS) have been around for more than two decades, but in recent years the trend has been to multi-coil systems such as Coil On Plug (COP) or Coil Per Cylinder (CPC) ignition systems, and Coil Near Plug (CNP) ignition systems.

COP systems have become the hot setup for a number of packaging, performance, emissions and maintenance reasons. Placing individual ignition coils directly over each spark plug eliminates the need for long, bulky (and expensive) high voltage spark plug cables. This reduces radio frequency interference, eliminates potential misfire problems caused by burned, chaffed or loose cables, and reduces resistance along the path between the coil and plug. Consequently, each coil can be smaller, lighter and use less energy to fire its spark plug.

From a performance standpoint, having a separate coil for each cylinder gives each coil more time to recharge between cylinder firings. With single coil distributor systems, the coil must fire twice every revolution of the crankshaft in a four-cylinder engine, and four times in a V8. With a multi-coil system, each coil only has to fire once for every revolution of the crankshaft. This provides more saturation time for a hotter spark, especially at higher rpm when firing times are greatly reduced. The result is fewer misfires, cleaner combustion and better fuel economy.

According to the original equipment suppliers who make...