Originally posted by E34EuroTouring@Apr 21 2005, 12:01 PM
Hi Kina,
Best to get a newer E30 M20B25 engine. There is less complications as the tranny length and drive-shaft will have to be taken from the donor car. I doubt if your current drive shaft will fit.
You will get the same issues using an M20 engine from an E34, although the block and head is roughly the same. You see that the intake runner (or the crab) is slightly different, and so is the AFM and also the ECU as well.
The M20B25 in the E34 is optimised for torque since it is a heavier car. Its ECU programme is highly tuned for the 5-series. You certainly can do similar tuning on the E30 M20 engine by getting those E34 used parts. eg AFM will fit. But Intake manifold (the crab) may not due to clearance issues.
I have seen an E30 with a 96 M50 engine. The M50B25 engine. Its poweful but that engine is HEAVY and completely throws off the balance of the car. It becomes ver front heavy, so can be dangerous. Thats why the S14 engine is popular since it is light.
You might also investigate using your M40B18 and stroke it to 2 litre or 2.2 litre. This will give you the needed torquer to make a difference while maintaining almost the same weight. It may be costly unless you can find second-hand parts somewhere.... Good luck.