In Reply to: ***For the motor experts only please*** posted by Tim Atl. on February 01, 2001 at 18:47:15:
I used the link mention to install an 88 635CSi eng, wiring harness and ECU into my 85 535i. That eng fits with NO eng mount fabrication required. I used the 88 intake manifold, inj, throttle body etc. 9.0:1 is more like the compression ratio. 10:1 is probably euro spec. I used my flywheel, clutch, starter, alternator, oil pan etc. IOW all the 85 external parts. AC is a perfect fit. Toughest part for me was matching the 88 eng wiring harness to my 85. I spliced 12 wires but only after I took the harnesses apart an confirmed the wiring. I look at your proposed other alternatives. The later model engs have the same comp, head etc, but different DME. From version 1.1 for the 88 to 3.1. Besides some eng mount fabrication, the eng wiring is not like the the early models. Specifically, the 88 635 wiring harness and ECU is like what you presently have. I put the ECU in the glove box same location. The later models E34 535 are different. In most cases wiring to the glove box were required lots of splicing. More than I wanted to take on. With this setup ALL the service lites etc work. In addition, with a diagnostic tool you can read fault codes. The ECU was chipped and I changed from a 3.73LS to a 3.46LS. The eng, ECU, combo has NO flat spots or hestitaion on acceleration. Feels quicker than the 3.73LS. Chipped most sites show 224HP with a cam swap it would be more. Basics are that it idles better and runs better than the early 3.5. Since it was available in 88, it would have been great is BMW put it is the 535is.