I have planned several ignition system tests for B series engines, so I purchased the ignition coils offered by BMW and the alternative. As an alternative, this time, I chose the Magneti Marelli ignition coil.
This ignition coil was purchased at the end of the Year 2023, but its manufacture year (printed on its body) is the beginning of the Year 2020. So, the ignition coil has been “delayed” on the warehouse shelf for three and a half years!
It’s not a surprise that its body corresponds to the “old” release of the BMW ignition coils.
Electrical parameters of the primary winding. BMW vs Magneti Marelli.
Inductance: 1.10/1.05 mH (-5%)
Active resistance: 410/520 mOhm (+27%)
It is clear that the ignition coils are not 1:1. Magneti Marelli ignition coils will have larger losses (due to +27% active resistance). Inductance is similar (5% less than the etalon), which means – in the Magneti Marelli ignition coil, a thinner wire is used. In addition – either fewer turns are wound or – a magnetic material of lower quality is used.
Is the Magneti Marelli ignition coil a 100% analog for the BMW coil? Of course, it is not.