BMW E21 M20 Swap Info

howtos e21 m20

Yes we understand the E21 did come with an M20.  This page will be more about how to install and wire an E30 M20 into the E21 chassis.  Also the only way to get the m20 into the E21 chassis normally is with the 323 subframe and a 323 transmission.  

We are offer M20 mounts that allow using the M10 subframe and complete E30 M20 and g260.  This does require an electric speedometer or a speedometer drive.

We will add to this How to over time but below is a bit of wiring information.


E21 C101 PinE30 C101 PinFunction
15oil presure light
313fuel pump
51alternator charge
66O2 relay sensor power
87ignition voltage to DME
134Coolant temp
159 (will need adapter)Tach
no connection12Check engine light ground