The 1975 (as well as 1974–1977) 911 Turbo was the first production 911 equipped with a magnetic pulse ignition distributor, replacing the traditional breaker point system. Instead of mechanical contacts, the ignition trigger signal is generated by a permanent magnet located inside the distributor.

As the 3.0-liter distributor shaft rotates, a six-lobed “star wheel” passes through the magnetic field, momentarily interrupting it. Each interruption creates the firing signal that is sent to the CDI unit and ignition coil.

Since this magnetic signal is very low in strength, the signal wire is protected by a braided shielding layer to prevent interference from electrical noise, especially from the high-voltage spark plug leads.