Wed Jan 01, 2020 7:00 pm
Apart from what Dan has alluded to, it's not so much that there's anything wrong with the Tu these days, it's just that there's no advantages over the plain M52. Historically, the Tu's integration with all the car's other systems led to all kinds of problems with getting the engine to perform properly, since the ECU was looking for all kinds of signals that don't exist on an E30, but now, thanks to the efforts of people like Dan and similarly minded others, these problems have been overcome or otherwise worked around. With each generation of BMW engines, the sophistication of the engine management goes up an order of magnitude, which is excellent if you're using the engine as and where BMW intended, but not so good if you are transplanting and/or modifying it.
As I said earlier, the electrical connections to the E30 wiring are much the same as any M5x conversion, but if your car is of the type after BMW discontinued the completely separate standalone engine loom, as used on the E30 and the earlier M5x engined BMWs, there's a bit more involved than just cutting off one plug and replacing it with an E30 C101 plug.