BMW E30 323 with M20B25
History : I'm helping a local guy named Peter Johansson in installing a Genboard on a M20B25 BMW inline 6 cyl engine with Bosch L-jetronic electronics and intake and distributor ignition. The M20B25 originally doesn't come in this configuration (Motronic only) but a previous owner swapped out the block and head of the 323 for 2.5 litre parts and retained the electronics and intake (very stupid, engine ran lean on too small injectors). The stock harness will be cut-up and partly re-used and directly wired to EC connectors - a lesson learned from previous BMW 728 project with similar electronics, meaning the stock L-jetronic connector and box will not be used.
[Picture: The car in question, needs paint and an engine]
![[Picture: The car in question, needs paint and an engine]](http://www.sehlstedt.nu/peppe/media/323TIC/8.JPG){kind=link}
![[Picture: of stock harness]](http://www.sehlstedt.nu/peppe/media/323TIC/3.jpg){kind=link}
The goal : Full featured Genboard that controls direct-fire ignition and sequential fuel injection on a turbocharged engine, preferrably with boost control. Low impedance injectors 400+ cc/min.
Backup plan : Unless we solve the trigger issues we will start off naturally aspirated using the distributor to trigger the Genboard and use the stock batch-fire harness (2 banks with 3 injectors each) and distributor ignition with single coil. Low impedance injectors is a problem here, we could temporarily use high impedance 192 cc/min injectors
Thoughts on triggers for the Genboard
A stock M20B25 comes with a 60-2 wheel at the crank, but this engine does not (due to decisions made by the previous owner who retained the L-Jetronic fuel injection instead). We can get a 60-2 wheel and install it on the crank, plenty of Motronic-based BMW engines that can donate such a wheel.
Plan : Install a trigger wheel on the crank for ignition timing and a trigger on the cam gear for cam sync/phase.
Question : Can we use the distributor instead of cam sync/phase ? We would have to cut off 5 of the 6 teeth, would the inductive pickup function as it's supposed to? Hard to answer. Maybe. There are some wishes for multitooth primary + multitooth secondary trigger setup (only makes sense for COP + historical arrangement optimized for minimal mechanical work). If that is realized only 1 teeth needs to be grinded. (It would be best to forget about using a distributor for anything..)
Question : Can we use a multi-tooth 60-2 wheel unmodified OR should we cut all but 3 teeth spaced 120 degrees apart?
A 60-2 crankwheel is the best you can get. Don't ruin it. If you run into InputTrigger/MultitoothProblem you can simply use a 150..220k in series with C38. Not hard at all, using the pads of the jumper that was originally for LM1815 pin5.
I'd definitely go with 60-2 crankwheel and wasted spark (3 transformers). If you only get 2 dual transformers or a 4-transformer pack (used for 8cyl wasted spark engines) you get a spare transformer and channel: in case of problem, after switching boots it takes only a small h[2] change.