Splitfire BMW Mini Cooper Coil packs

Conventional type of ignition system distributes electricity from an ignition coil to each spark plug through spark plug wires. On the other hand, direct ignition system has each coil pack on respective spark plugs. So an increased voltage is provided to each spark plug directly from respective coil pack. The main difference between plug wires and direct ignition system is the distance between coil pack and spark plug.

In case of Plug Wire System, the voltage is increased by one coil pack and sent to respective spark plug through distributor and individual plug wires, and therefore, the voltage will be decreased at each process before the electricity reaches to spark plug. But, incase of Direct Ignition Systems, each coil directly sends an increased voltage to spark plug without any loss of electricity. Moreover, the best ignition timing is gained by computer and is controlled by ECU along with fuel injection system. The strong point of Direct Ignition System is to provide an accurate ignition and to maintain stable secondary voltage at high RPM.